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2020 Planning Strategies for Improving Resilience of Cities in Developing Countries to the Urban Heat Island Caroline Lucienne Knowles

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THE FLORIDA STATE UNIVERSITY

COLLEGE OF SOCIAL SCIENCES

AND PUBLIC POLICY

PLANNING STRATEGIES FOR

IMPROVING RESILIENCE OF

CITIES IN DEVELOPING

COUNTRIES TO THE URBAN HEAT

ISLAND EFFECT

By

CAROLINE KNOWLES

A Thesis submitted to the Department of International Affairs in partial fulfillment of the requirements for graduation with Honors in the Major

Degree Awarded: Spring, 2020

The members of the Defense Committee approve the thesis of Caroline Knowles defended on April 13, 2020.

Dr. John Felkner Thesis Director

Dr. Janet Dilling Outside Committee Member

Dr. William Butler Committee Member

Dr. Christopher Coutts Committee Member

Abstract With climate change and global warming, the detrimental socio-economic impacts of Urban Heat Island (UHI) effect are increasing, with cities in developing countries particularly vulnerable. This thesis conducts a literature review to identify the causes, socio-economic impacts, and urban planning mitigation strategies that can be used against the UHI effect. Further, this research focuses on the specific UHI impacts, consequences, best mitigation strategies and particular challenges for cities in developing countries, addressing a notable gap in the literature on these dimensions. Several key impacts of UHI are noted, including lower economic productivity, heightened public health risks, and increased energy consumption. Specific vulnerabilities of cities in developing areas are also identified. These include dependence on environmentally linked industries, disadvantageous geographic location, and rapid rates of urbanization. Weak governance and poor infrastructure also play a role in a city’s vulnerability; however, these concerns lack substantial academic backing and require further research to fully evaluate their impact on UHI. Broadly, research on the connection between UHI and particular vulnerabilities of cities in developing areas is sparse, leading to a noticeable gap in the academic literature. Numerous UHI mitigation strategies, both in urban design and public policy, are broadly explored before several specific strategies are identified as most feasible for cities in developing areas. Such tactics include increasing green space and vegetation, implementation of green roofs, use of cool building materials and modification of urban form. Structural and cultural challenges associated with successful implementation of these mitigation strategies in cities in developing areas is also assessed; barriers include poor governance and lack of capacity, poor awareness at the local and municipal level, an inability or unwillingness to finance these strategies, differing attitudes and values among residents, and an absence of research and data.

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Table of Contents 1.0 Introduction ...... 7 1.1 Statement of central research question and subsidiary research questions ...... 7 1.2 Methodology followed in this study...... 8 1.3 How the paper is organized ...... 9 2.0 What is the urban heat island effect? ...... 9 2.1 Introduction ...... 9 2.2 Urban Heat Island (UHI) effect ...... 10 2.3 Atmospheric UHI ...... 10 2.4 Surface UHI...... 11 2.5 Temperature change associated with UHI ...... 11 3.0 Physical causes of UHI ...... 12 3.1 Introduction ...... 12 3.2 Weather ...... 12 3.3 Reduced vegetation in urban areas ...... 12 3.4 Modification of land surfaces and land use change ...... 13 3.5 Anthropogenic heat from automobile and industry ...... 14 3.6 High rates of pollution ...... 14 3.7 Background climate and geographic location of city ...... 15 3.8 Properties of urban materials ...... 15 3.9 Urban geometry and design ...... 16 4.0 Major Socio-economic impacts of UHI ...... 17 4.1 Introduction ...... 17 4.2 Energy and environmental impacts ...... 17 4.3 Health impacts ...... 18 4.4 Economic consequences ...... 19 5.0 Vulnerability of cities in developing countries to climate change and UHI ...... 20 5.1 Introduction ...... 20 5.2 Vulnerability of cities in developing countries to climate change ...... 21 5.2.1 Dependence of environmentally linked industries ...... 21 5.2.2 Disadvantageous geographic location ...... 21 5.2.3 Rapid urbanization ...... 22 5.2.4 Preexisting water struggles ...... 23 5.3 Vulnerability of cities in developing countries to UHI ...... 24 5.4 Most vulnerable global regions to climate change and UHI ...... 26 5.4.1 West and sub-Saharan Africa ...... 26

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5.4.2 South-East Asia ...... 28 5.4.3 South Asia ...... 29 6.0 UHI mitigation strategies...... 30 6.1 Introduction ...... 30 6.2 Review of major UHI mitigation strategies ...... 30 6.2.1 Trees and vegetation ...... 31 6.2.2 Urban green spaces ...... 33 6.2.3 Green roofs ...... 35 6.2.4 Vertical greening; vegetated facades and walls ...... 38 6.2.5 Building materials ...... 40 6.2.6 Cool roofs ...... 42 6.2.7 Cool pavements ...... 44 6.2.8 Heat island reduction policies ...... 47 6.2.9 Modification of urban form ...... 49 6.3 Mitigation strategies particularly valuable for cities in developing countries ...... 50 6.3.1 Introduction ...... 50 6.3.2 Increased green space and vegetation ...... 51 6.3.3 Green roofs ...... 53 6.3.4 Use of cool building materials ...... 54 6.3.5 Urban morphology and form ...... 55 6.4 Specific challenges associated with implementing UHI mitigation strategies in cities in developing countries ...... 56 6.4.1 Introduction ...... 56 6.4.2 Poor governance, capacity, and coordination ...... 57 6.4.3 Inability to finance mitigation strategies ...... 58 6.4.4 Lack of awareness and communication ...... 59 6.4.5 Differing attitudes, values, and motivations ...... 60 6.4.6 Absence of research and reliable data ...... 60 7.0 Conclusion ...... 61 Tables ...... 62 References ...... 67 Appendix: Literature Reviews on Planning Strategies for Cities in Developing Countries to Climate Change Impacts ...... 80 Planning strategies for cities in developing countries for sea-level rise mitigation through governance or policies ...... 80 Planning strategies for cities in developing countries for sea-level rise mitigation through engineering and infrastructure changes ...... 82 Planning strategies for cities in developing countries for increased flooding due to climate change ...... 83 Planning for climate change’s impact on food security in developing countries ...... 85 Planning strategies to decrease uncertainty and improve resiliency city planning (RCT) ...... 86 How the World Bank is approaching climate change in developing countries ...... 87 Ecosystems services and climate change ...... 89 Consideration of social-ecological systems in planning for climate change ...... 91

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Food-Energy-Water (FEW) framework and planning for climate change ...... 93

List of Tables

Table 1. Physical causes of Urban Heat Island Effect (UHI) ...... 62 Table 2. Negative impacts of the Urban Heat Island Effect (UHI) ...... 63 Table 3. UHI Mitigation Strategies ...... 64 Table 4. Review of feasible UHI mitigation strategies in developing cities ...... 66

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1.0 Introduction

Though Stephan Hawking was once quoted saying, “One can’t predict the weather more than a few days in advance”, growing understanding of climate change and its consequences have led scientists, engineers, and planners to begin to consider the impact a shifting climate will have in reshaping the physical and socioeconomic landscape of an increasingly globalized world. One such effect, notably warmer temperatures in urban areas, is of particular importance due to the significant nature of its impact. Defined as an urban heat island (UHI), this phenomenon occurs when a built-up urban area is noticeably hotter than its surrounding rural area. As cities develop and the built environment expands, vegetation is lost, and most natural surfaces are paved or covered by buildings. Modification of ground cover as well as materials used in construction absorb and trap the sun’s rays, raising surface heat levels. UHI has significant, serious and documented negative impacts, including increases in energy consumption, reductions in economic productivity, and increased public health risks. Numerous mitigation strategies have been developed to lower urban temperatures including increased vegetation, vertical greening, green roofs, and the use of cool materials. While a large portion of the academic literature has been dedicated to analyzing the causes and consequences of UHI, particularly in developed cities, less attention is given to cities in developing regions. More likely to bear the costs of climate change while facing rapid rates of urbanization, cities in developing countries are quickly heating up, though most lack the financial and structural capacity of their counterparts in wealthier countries to adequately address such concerns.

1.1 Statement of central research question and subsidiary research questions

The primary research question of this study is: What are the challenges particular to cities in developing areas from UHI effect, and what are the most feasible and effective UHI effect mitigation strategies for those cities? Subsidiary research questions included the following: • What are the primary UHI effect planning mitigation strategies for all cities in general? • What are the primary negative socio-economic impacts of UHI effect? • What are the key particular vulnerabilities of cities in developing countries to UHI effect? • Which global developing regions are most likely to experience UHI effect?

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1.2 Methodology followed in this study

This research was completed through a rigorous review of secondary sources: literature and, in some cases, secondary data. The primary focus of the literature review was peer- reviewed academic studies. However, in addition, non peer-reviewed but highly relevant and valuable reports and studies, including those completed by international development agencies such as The World Bank and the United Nations, as well as reports from national government agencies such as the US Environmental Protection Agency (US EPA), were reviewed. Literature review was conducted through rigorous searching of peer-reviewed and non peer-reviewed sources using systematic keyword search phrases, which were then systematically modified based on trends from the literature. Literature sources, abstracts and PDFs of papers were systematically compiled using the Mendeley bibliographic software. In some cases, relevant secondary data compiled by reputable sources was also reviewed to identify key trends. The initial focus of this Honors Thesis research was not confined only to UHI effect planning strategies for cities in developing countries and developing areas, but more broadly to cities in developing areas planning strategies for climate change mitigation. In the Fall of 2019, a much broader literature review was completed, under the supervision of the Honors Thesis Director, on the following topics: 1. Planning strategies for cities in developing countries for sea-level rise mitigation. For this, two sub-topics were researched: A. Planning strategies for sea-level rise mitigation through infrastructure or engineering approaches B. Planning strategies for sea-level rise mitigation through governance or policies that do not involve actual infrastructural changes, such as tax incentives, etc. 2. Planning strategies for cities in developing countries for increased flooding due to climate change 3. Planning strategies for climate change’s impact on food security in developing countries 4. Planning strategies to reduce uncertainty and improve resiliency city planning (RCT) 5. Ecosystem services and climate change 6. Consideration of social-ecological systems in planning for climate change 7. Food-Energy-Water (FEW) framework and planning for climate change

The results from these preliminary literature reviews on these broader topics is presented in the Appendix.

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Beginning in December 2019, the research focused exclusively on planning mitigation strategies for cities in developing countries to UHI effect, and the literature review intensified on that narrowed focus.

1.3 How the paper is organized

This Thesis is organized as follows: Section 2.0 describes the UHI effect, including atmospheric UHI effect and surface UHI effect, along with documented UHI effect temperature variations. Section 3.0 reviews the primary physical causes of UHI. Section 4.0 describes the major negative socio-economic impacts of UHI. Section 5.0 focuses on the vulnerability of cities in developing countries both to broader climate change impacts and to UHI, including first a review of factors that exacerbate the vulnerability of cities in developing countries to broader climate change impacts, then a discussion of specific factors that make such cities particularly vulnerable to UHI effect, and finally a discussion of global developing regions most vulnerable to UHI. Finally, Section 6.0 focuses on UHI planning mitigation strategies, including first a review of major UHI mitigation strategies, then an identification of UHI mitigation strategies particularly feasible or effective for cities in developing countries, and then a discussion of specific challenges associated with implementing UHI mitigation strategies in cities in developing countries. Section 7.0 presents the Conclusion, followed by Tables, References and the Appendix.

2.0 What is the urban heat island effect?

2.1 Introduction

As cities continue to develop and urban boundaries continue to inflate, so too will urban temperatures. In order to obtain a better understanding of UHI, in which urban areas are warmer than their rural counterparts, it is critical to establish the scientific groundwork on the phenomenon. After a brief introduction on the history of the understanding of the phenomenon, the two primary variations of UHI - atmospheric UHI and surface UHI - are defined. Notable temperature differences in both domestic and international cities are also noted in the final section.

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2.2 Urban Heat Island (UHI) effect

Prior to exploring the causes of UHI and the socio-economic consequences the phenomenon imparts on cities it is first important to explain what UHI is and the nature of the effect. First documented as “reverse oases” in a study of London’s climate in 1818 by amateur meteorologist Luke Howard, the full technical term “urban heat island” was coined in the 1940s, to describe higher surface and air temperatures in cities as compared to their suburban and rural surroundings (Kumar et al., 2017). UHI can be distinguished into two broad ‘types’: atmospheric UHI and surface UHI. While both fall under the same umbrella, it is important to distinguish between the two as both differ in the ways they are formed, their impacts, and the methods available to mitigate them (Cole et al., 2008). 2.3 Atmospheric UHI

Atmospheric UHI refers to the temperature difference between warmer air in urban areas as compared to cooler air in nearby rural surroundings (Cole et al., 2008). Experts often divide this type of heat island into two sub-categories: canopy layer UHI and boundary layer UHI. Canopy layer UHI exists in the layer of air where people live and extends from the ground to below the tops of trees and roofs, whereas boundary layer UHI starts at the treetop and rooftop level and extends to the altitude point where urban landscapes lose their warming influence over the atmosphere (Cole et al., 2008). These two types of atmospheric UHI engage in strong diurnal behavior, becoming more pronounced at night and predawn due to the slow release of heat from urban infrastructure (Cole et al., 2008; Li et al., 2018). In diurnal behavior, urban heat islands raise atmospheric urban night-time temperatures more than day-time temperatures (IPCC, 2001). During the day, urban surfaces are heated by solar reflection and absorption, at night those surfaces continue to emit stored heat energy. The lack of solar radiation coupled with the heat emitted from infrastructure as it begins to cool down creates an inversion layer on the city surface. The inversion layer traps air near the surface keeping surface air hot from still warm urban surfaces, resulting in warmer nighttime temperatures (IPCC, 2001; Kumar et al., 2017). On a seasonal level, atmospheric UHI is also found to be greater during the winter months. In areas where snow and high rural winds are common in winter, an atmospheric UHI rural-urban difference is particularly pronounced (Kumar et al., 2017). This is due in part to the fact that

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snow melts more quickly in urban areas than in rural, due to UHI, thus lowering the albedo of the city and heightening the heating effect. However, both diurnal and seasonal variation is conditional and often depends on other external factors, including the propensity and density of urban and rural surfaces, the season, and preexisting weather conditions (Cole et al., 2008). 2.4 Surface UHI

Surface UHI describes the temperature difference between dry, exposed urban surfaces such as roofs and pavement, and shaded or moist surfaces, more commonly found in rural areas (Cole et al., 2008). This form of UHI is often present both day and night but, unlike atmospheric UHI which peaks during nighttime, tends to be strongest in the daytime when the sun is shining. As with its atmospheric counterpart, the degree of surface UHI also varies seasonally. This is due to the variation of the sun’s intensity as well as variable changes in ground cover and weather patterns throughout the year. Given these conditions, surface UHI is typically more pronounced in the summer when skies are clear, the sun is strong, and the wind is calm (Cole et al., 2008). While this form of UHI is explored in the academic literature, its complement, atmospheric UHI, is more frequently measured in meteorological research. 2.5 Temperature change associated with UHI

Generally speaking, published temperatures changes found with UHI vary depending on the type of UHI in question and the location and size of the nation, region, or city. In regard to the differences between surface UHI and atmospheric UHI in American cities, variation in temperature is largely dependent on spatial and temporal features. Surface UHI exhibits more variation, with urban-rural temperature differences peaking on average at a 10 to 15 °F variance during the day and 5 to 10 °F at night (Cole et al., 2008). Atmospheric UHI exhibits less variation and intensity, peaking at a difference of 1 to 3 °F in the daytime and 7 to 12 °F at night (Cole et al., 2008). The rise of mega-cities, especially in the global south, have also promoted a strong variation in surface and atmospheric UHI. However, such temperature changes are challenging to standardize as most are measured on a city-by-city basis. Mexico City has experienced a 2 °C temperature increase in the past century, while rural/ urban temperature differences in Kuala Lumpur can reach up to at 7°C difference (Elsayed, 2012; Thundiyil, 2003).

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3.0 Physical causes of UHI 3.1 Introduction

The formation and perpetuation of UHI can be caused a number of environmental and societal influences. Shifting weather patterns, including reduced wind speed and increased cloud cover, as well as the geographic location of the city impacts the growth of UHI. Atmospheric degradation stimulated by human activity also serves as a powerful catalyst for rising urban temperatures. This section serves to assess the primary environmental and physical factors that can lead to the development of UHI effect, many of which in turn are driven by anthropogenic socio-economic processes. As noted below and in Table 1, these features include weather, reduced vegetation in urban areas, modification of land surfaces and land use change, anthropogenic heat from automobiles and industry, high rates of pollution, background climate and geographic location of city, properties of urban materials and urban geometry and design. 3.2 Weather

Two primary weather conditions influence the development and rate of UHI within cities: wind and cloud cover (Cole et al., 2008). UHI is typically strongest during periods of calm winds and clear skies, as these conditions maximize the amount of solar energy reaching urban surfaces and minimizes the amount of heat that can be convected away. Equally, strong winds and cloudy skies minimize the potential for UHI development. Research into changes in global climate extremes in urban areas also indicate that global urban centers are experiencing heat waves and hotter nights at greater rates around the globe (Mishra et al., 2015). Such increases in temperature are largely driven by changes in the mean and distribution of air temperatures, which is impacted by a host of external factors including climate variability, climate warming, and land use changes. These findings coupled with patterns of decreased frequency of extreme windy days in major urban cities (research conducted by Mishra et al., 2015 noted that 60% of sites observed experienced a significant decline) create prime conditions for the advance of UHI conditions in major urban hubs. 3.3 Reduced vegetation in urban areas

Lack of vegetation and consequently reduced evapotranspiration play an important role in promoting UHI in urban areas. Rural areas are dense with vegetation and open land, providing much needed shade, which in turn lowers surface temperatures. Thick vegetation also promotes

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the process of evapotranspiration, in which plants release water to the surrounding air, thus cooling the surfaces around them (Cole et al., 2008; Kokthar et al., 2019) In contrast, urban areas are characterized by dry, impervious surfaces including paved roads, parking lots, sidewalks, and conventional roofs, with highly urbanized areas characterized by 75-100% impervious surfaces (Cole et al., 2008; Yuan & Bauer, 2007). As vegetation is cleared and surfaces paved, the resulting change in ground cover results in less shade and moisture to keep the area cool. With less surface moisture available for evapotranspiration, built areas evaporate less water and consequently experience higher surface and air temperatures (Cole et al., 2008; Taha, 1997). Such difference is exemplified in cities across the globe; in Tokyo, vegetated surfaces are on average 1.6 degrees cooler than non-vegetated spots and in Montreal, urban parks can be 2.5 degrees cooler than surrounding areas (Taha, 1997). Thus, a strong relationship between the expansion of impervious surfaces (and conversely the reduction of vegetated surfaces) accounts for much of the variation in land surface temperature dynamics (Kokthar et al., 2019). 3.4 Modification of land surfaces and land use change

Urbanization, and its accompanying increases in greenhouse gas emissions and land use change, is considered to be one of the most transformative aspects of human impact on the environment and can directly affect mean surface temperatures of urban areas (Guo et al., 2015). Areas that are covered by vegetation and water are found to exhibit lower surface temperatures, whereas central portions of cities and areas with dense urbanization exhibit the highest surface temperatures as compared to the surrounding areas (Kumar et al., 2017). As cities develop, vital green space and open area necessary for evapotranspiration, shading, and rainwater retention disappear and are replaced with impervious surfaces, leaving cities without proper cooling channels (Guo et al., 2015). As populations grow, city centers continue to expand, and temperatures continue to rise. Currently, 54% of the world’s population lives in urban centers with another 2.5 billion urban dwellers expected to arrive by 2050 (Guo et al., 2015) (Oke, 1973). Population pressures on the land, including increasing pressure on industrial and housing areas, are anticipated to expand UHI effects by a global rate of 4.47% a year (Guo et al., 2015). Manipulation of land use changes and its associated impacts on UHI, driven by urbanization, allow the base conditions through which all drivers of UHI flow, including reduced vegetation, increased anthropogenic heat, urban geometry and design, and increased rates of pollution.

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3.5 Anthropogenic heat from automobile and industry

Anthropogenic heat, or heat that is generated by cars, air conditioners, industrial facilities, and a variety of other man-made sources, heavily contributes to the development of UHI (Cole et al., 2008; EMPRI, 2017). Anthropogenic heat emission often manifests in two forms: sensible heat emission and rejected heat emission (EMPRI, 2017). Sensible heat emission into the atmosphere can come directly from chimneys, air conditioners, heaters, and building convection. Rejected heat occurs when cooling systems in buildings consume energy to reject heat from the building into the urban environment (EMPRI, 2017). While levels of anthropogenic heat vary depending on a cities’ energy use, power generation and transportation system, the largest rates of anthropogenic heat are typically found in cold-climate urban centers during the winter months (Taha, 1997). Such elevation can be explained by the intensive heating load needed during that season. Anthropogenic heat and population density are also closely linked, as the spatial distribution of energy consumption is spatially correlated with the intensity of human activity (Li & Zhao, 2012) (Fan & Sailor, 2005). High energy consumption regions, which often include many large cities, are characterized by dense populations, significant change in land use, high economic activity and pollutants, and high energy consumption (Li & Zhao, 2012). Such density, when paired with energy use patterns in buildings and transportation systems, can create UHI up to 2-3 degrees warmer in city centers both day and night (Taha, 1997). The effects of anthropogenic heat are synergistic with other UHI driving factors, including reduced vegetation and dark materials. 3.6 High rates of pollution

High levels of pollution can also increase UHI in urban areas, as many forms of pollution modify the radiative properties of the atmosphere (Cao et al., 2016). Such formation establishes a cyclical relationship, in which higher temperatures increase energy demand, which generally causes higher levels of air pollution and greenhouse gas emissions, thus further raising urban temperatures and exacerbating demand. Most electricity produced in urban hubs is derived from fossil fuels (Cole et al., 2008). Pollution produced from fossil fuel burning from energy production, fossil-fuel powered industries and transportation systems can contribute to complex air problems and increase the rate of ground-level ozone formation, which is in turn accelerated by increases in temperature (Sanford, 2011). As a result, urban atmospheres have more pollution

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particles than surrounding rural atmospheres. Known as the Urban Pollution Island (UPI) phenomenon, UPI and UHI often interact with each other (Li et al., 2018). UHI-related temperatures often promote the dispersion of pollution particles to higher atmospheric boundaries, while UPI pollutants can trap earth-emitted radiation and reemit radiation back to the Earth’s surface (Li et al., 2018) (Zheng et al. 2018). The presence of both heat and stress and air pollution in cities makes urban populations immensely vulnerable to the effects of each respective threat. 3.7 Background climate and geographic location of city

Climate and topography, which are in part determined by a city’s geographic location, influence UHI formation (Cole et al., 2008). Cities that are located on large bodies of water are more likely to have relatively moderate temperatures, as the water generates winds that convect heat away from the city center. Urban centers located in more mountainous regions also have varying levels of UHI, as mountains can both block vital winds from penetrating the city or create wind patterns that pass through the city (Cole et al., 2008; Mohajerani et al., 2017). The background climate also plays a role in determining a city’s vulnerability to UHI. Research has found that cities located in wet climates are more likely to experience UHI where high temperatures effects are compounded by excessive air humidity (Zhao et al., 2014). This is due in large part to the topographic composition of the land, which is often heavily vegetated and aerodynamically rough (Zhao et al., 2014). Such composition inhibits the convection efficiency of urban areas and temperatures rise accordingly. Conversely, the opposite occurs in dry climate zones where non-urban surrounding areas are more conducive to convection efficiency (Zhao et al., 2014). The result is actually a cooling effect, in which the urban land is more efficient in cooling itself than its rural counterparts. While local terrain and background climate play a necessary role in the cause of UHI, both play a more significant role when large-scale effects, such as wind patterns, are minimal. 3.8 Properties of urban materials

Properties of urban materials, including their solar reflectance, urban emissivity, and heat capacity, also influence UHI development as they play a critical role in determining how the sun’s energy is reflected, emitted, and absorbed (Cole et al., 2008). Energy emitted from the sun plays a formative role in UHI development and can be transmitted through a host of light waves,

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including ultraviolet (UV rays), visible light, and infrared energy. Solar reflection, or albedo, is the percentage of solar energy reflected by a surface (Cole et al., 2008) (Solecki et al., 2005). Much of the solar energy that reaches the Earth’s surface comes in the form of visible wavelengths; thus, solar reflection is closely correlated with a material’s color. Darker surfaces have lower solar reflectance than lighter surfaces. Translated into an urban schema, cities are primarily comprised of surface materials, such as roofing and paving, that have lower albedo than those in rural settings (Cole et al., 2008) (Solecki et al., 2005) As a result, built environments absorb more of the sun’s energy, raising temperatures and contributing to the formation of UHI. Material’s thermal emittance (emissivity) also plays a role in determining its surface temperature. Measured by a surface’s ability to shed heat, emissivity is relatively high in most construction materials (with the exception of metal) (Cole et al., 2008). This means that surfaces with high emissivity will stay cooler, because they release heat more readily. However, a material’s heat capacity can counter high rates of emissivity. Many urban building materials, such as steel and stone, have higher heat capacities than rural materials (Cole et al., 2008) (Solecki et al., 2005; Mohajerani et al., 2017). As a result, urban centers are more effective at storing heat within its infrastructure. Varying combinations of thermal bulk properties (heat capacity) and radiative properties (albedo and emissivity) exist within materials used in urban areas, leading temperatures to rise in urban infrastructure as it traps heat throughout the day. 3.9 Urban geometry and design

Urban geometry, which refers to the dimensions and spacing of buildings within a city, also serves as an additional factor in UHI development (Cole et al., 2008; EMPRI, 2017). It may directly influence wind flow, energy absorption and a surface’s ability to emit heat back into the environment. Buildings are easily influenced by objects surrounding them and in many built environments surfaces and structures are at least partially obstructed by entities that prohibit buildings from releasing their heat readily (Cole et al., 2008). One key aspect of urban geometry involves the presence of urban canyons, which are often illustrated by relatively narrow streets lined by tall buildings (emulating a canyon like environment) (Cole et al., 2008; EMPRI, 2017). During the day, urban canyons can create shade and reduce surface temperature, however the tall buildings also disproportionally reflect and absorb the sun’s energy which can lower a city’s albedo and raise surface temperatures. At night, urban canyons impede cooling, as buildings and structures block the heat being released from urban infrastructure (Cole et al., 2008). Tall

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buildings also block necessary wind flow in urban areas, which inhibits convection cooling and prevents pollutants from dissipating (Rajagopalan, Lim, & Jamei, 2014; EMPRI, 2017).

4.0 Major Socio-economic impacts of UHI 4.1 Introduction

Rising urban temperatures can impart severe consequences on nearly every facet of city life, creating a cycle of poor living conditions and quality of life for urban residents. Hotter temperatures caused by UHI increases energy use in cities and consequently air pollution levels. Extended periods of warmer weather coupled with unclean air exacerbates not only heat-related illnesses but chronic respiratory conditions such as asthma. Warmer temperatures decrease worker productivity, thus slowing a city’s economic growth. This section, as well as Table 2 below, summarizes the major socio-economic impacts of UHI effect. These consequences can be categorized into three main categories: energy and environmental impacts, health impacts, and economic consequences.

4.2 Energy and environmental impacts

Energy and environmental adverse impacts that have been associated with increased urban heat include increased energy consumption, elevated greenhouse gas emissions and air pollution (Cole et al., 2008; Arifwidodo & Chandrasiri, 2015; Liao et al. 2017; Li et al., 2019). Increased temperatures during warmer months in cities intensify the demand for energy use (primarily for air conditioning) in the range of 1.5 to 2 percent for every 1-degree Fahrenheit increase in air temperatures, starting at 68 degrees Fahrenheit (Rinkesh, 2019; Cole et al., 2008). These increases in overall electricity demand, especially during peak hours when city residents are most likely to be running cooling systems, lights and appliances, can overload local and regional power grids (Cole et al., 2008; Arifwidodo & Chandrasiri, 2015). As temperatures have continued to increase in downtown areas in recent decades, five to ten percent of community-wide demand for electricity is now used to compensate for UHI (Cole et al., 2008). During extreme heat events, local municipalities have in some cases been forced to implement controlled, rolling brownouts or blackouts to avoid major power outages (EPA, 2008). Increased use of electricity is also linked to the elevation of greenhouse gas emissions in cities, as power plants use fossil fuels to supplement energy production

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mechanisms (Cole et al., 2008). This leads to increased volumes of heavy pollutants and also contributes to complex air quality issues such as the formation of smog, fine particulate matter, and acid rain (EPA, 2008). Thus, UHI leads to increase energy usage, in turn leading to increased emissions and particularly pollution, which in turn can intensify the UHI, resulting in UHI feedback mechanisms. 4.3 Health impacts

Increasing temperatures also contribute to compromised human health and comfort levels, as fluctuating temperatures and higher levels of air pollution can exacerbate general discomfort and preexisting respiratory conditions as well as induce heat cramps and exhaustion, heat strokes, and even heat-related mortality (Cole et al., 2008; Baccini et al., 2008; O’Neill & Ebi, 2009; Patz et al., 2005). Heat-related mortality follows a J-shaped curve with a steeper slope at higher temperatures and sensitive populations are more likely to be at particular risk during extreme heat events (Rinkesh, 2019; Patz et al., 2005). Extended periods of warmer weather coupled with longer and more intense heatwaves severely compromises the health and wellbeing of city residents, especially those most vulnerable to extreme variations in temperature including children, the elderly, and low-income populations. Other socioeconomic factors, including being less educated, socially isolated, and non-white also play a critical role in determining one’s vulnerability to the effects of UHI (O’Neill & Ebi, 2009). While several health impairments, such as heat stroke, dehydration, heat cramps, and heat exhaustion, can be directly attributed to warmer urban environments, urban heat often worsens pre-existing conditions more so than it kills directly (Peterson, 2017; O’Neill & Ebi, 2009). Chronic conditions such as asthma, heart and lung disease, kidney problems, and diabetes have worsened for residents living in warmer environments (Heaviside et al., 2017). Given that children are more prone to spend time outdoors and have an insufficient ability for physiologic adaption, they are found to be more prone to the effects of heatwaves while members of the elderly population report higher rates of respiratory illnesses during periods of extreme heat (Sarofim et al., 2016). Low income elderly populations living in row homes are particularly vulnerable to the effects of increasing temperatures (Cole et al., 2008). The design of the homes, which often lack air conditioning and proper ventilation systems, coupled with the fact that much of the elderly population lives alone makes heat events potentially deadly for this demographic. Many elderly citizens may not have friends and family nearby, may not report to work regularly, and many

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lack neighbors who can check in on them, often leaving them stranded during extreme heat events. Such isolation may also prohibit them from hearing vital warnings about impending heat and recommendations for how to cope. Such social vulnerability coupled with their body’s inability to handle heat stress make the elderly population particularly suspectable to the negative effects of UHI (Cole et al., 2008; O’Neill & Ebi, 2009). 4.4 Economic consequences

Rising temperatures stemming from the urban heat island effect can have severe economic consequences, particularly as climate change continues to intensify heat waves and lengthen warmer months. Cities’ economic losses are expected to be 2.6 times higher than they would be if the UHI effect was not taken into consideration (Mike, 2017). Increasing temperatures primarily affect economic activity in two ways: influencing both the level of output and the economy’s ability to grow (Dell et al., 2012). Focusing specifically on agricultural production, warmer temperatures negatively impact overall agricultural output by 2.66% for every increase by 1°C, with drier nations (those that receive below average precipitation levels) feeling a more pronounced impact (Dell et al., 2012). Production is also limited in the industrial sector, with a 1°C Celsius higher temperature in poorer countries linked to a 2% decline in industrial output (Dell et al., 2012). Several explanations can be attributed to lower production levels, including demand-side spillover from lower agricultural output and the nature of the industries involved in industrial production (such as electronic equipment and light metal manufacturing) (Daanen et al., 2013; Sudarshan & Tewari, 2014). However, one of the largest contributors to lower manufacturing rates and consequently slower economic growth is the heat-related loss of work productivity. Heat stress negatively affects the health of workers and lowers work productivity (absenteeism, diminished work capacity, and loss of productivity) by altering the ambient work environment (Yu et al., 2019; Lundgren et al., 2013; Sudarshan & Tewari, 2014; Singh et al., 2015). Warmer temperatures coupled with a lack of proper cooling mechanisms can raise the core body temperature of factory workers above 38 °C (100F), significantly altering their physical and mental capacities. Given that workers’ health is a key component in determining overall economic productivity, the effect of heat stress can have a significant impact to overall economic production (Lundgren et al., 2013; Sudarshan & Tewari, 2014). Research has indicated that if current trends continue, global work productivity will fall approximately 28% by 2050, with

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certain vulnerable regions, such as Southeast Asia, feeling the economic impacts of a warming world even sooner (Yu et al., 2019). Given that many cities’ economies are tied to industrial regional or national output, increasing temperatures will not only compromise individual workers productivity but have regional or national impacts. Finally, warmer urban temperatures can harm sensitive aquatic ecosystems as heated stormwater is released into streams, rivers, and lakes in the form of thermal pollution (Cole et al., 2008; Somers et al., 2013). A shift in water temperatures often threatens the stability of aquatic life, with warmer temperatures compromising the metabolism and reproduction of many aquatic species (EPA, 2008). For cities in coastal areas this can prove to be devastating as local economies are often dependent on fishing or other marine related activities for sustainment. As climate change continues to worsen these impacts, special attention must be paid to the areas who will bear the brunt of these harsher heat events. Due in large part to high rates of urbanization and rapid development, these areas will likely include cities in developing countries, many of whom are least equipped to tackle the issue.

5.0 Vulnerability of cities in developing countries to climate change and UHI

5.1 Introduction Urban areas in developing countries, primarily those in the global South, are particularly vulnerable to the effects of UHI. This is due in large part to a proposed host of structural and socio-economic issues including a pronounced lack of green space, greater presence of polluting industries, heightened air and water contamination, weak governance structures, poorer infrastructure, mounting population pressures, fewer financial resources and disadvantageous geographic locations (World Bank, 2010; IPCC, 2014; Mertz et al., 2009; Sachs et al., 2001; Denton, 2002; Manoli et al., 2019; Ravindranath & Sathaye, 2002). While several of these reasons are well explored within the academic literature, others are lacking in notable research especially in regard to their role in developing countries. Concerns such as weak governance structures and lack of infrastructure within cities in developing areas lacks robust research and will require further exploration to fully assess their impact on UHI. More broadly speaking, research on the connection between UHI and particular vulnerabilities of cities in developing countries is also minimal, leaving a pertinent gap in the academic literature that will require further attention moving forward.

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5.2 Vulnerability of cities in developing countries to climate change

In an effort to frame cities in developing areas vulnerability to UHI, it is first important to examine the physical and socio-economic forces that shape these cities vulnerability to climate change. Several of these conditions can potentially exacerbate UHI at the city-level; these include disproportionate reliance on weather-variable industries, poor geographic location, rapid urbanization, and preexisting water struggles. 5.2.1 Dependence of environmentally linked industries

As the global economy continues to expand, developing countries are beginning to play a more pronounced role in the international marketplace. Such participation is exemplified by the fact that the 220 largest cities in developing regions contributed 10% towards the global GDP in 2007, with China and Latin American cities each contributing 4% towards the total (Dobbs et al., 2011). As the gravity of the urban world continues to move south and developing countries continue to enter into the market fold, greater attention will be placed on the economic output and productivity of these nations. Despite an uptick in economic diversification in recent decades, many developing countries still rely heavily on environmentally or weather linked industries including agriculture and tourism activities (World Bank, 2013; US AID, 2017; Hoogendoorn & Fitchett, 2018). As climate change furthers environmental degradation, including extended periods of drought and poor soil quality, critical ecosystems and vital farming land are becoming more fragile and more likely to be affected by climate variability (Denton, 2002; US AID, 2017). Heavy dependence on agriculture makes many developing regions, including Southeast Asia and Western Africa extremely vulnerable to climate shocks. Decreased yields from farming will leave many people unemployed, with few economic opportunities and low levels of education driving residents into already overpopulated urban areas (USAID, 2017). Elevated temperatures and longer heatwaves will also disrupt economic activity by reducing the productivity of workers. In low-income countries, these climate related losses can be up to 5.5% of the national GDP and are likely to increase in the future (Tan & Siri, 2016). 5.2.2 Disadvantageous geographic location

A city’s geographic location plays an important role in determining its vulnerability to climate change. Traditionally, cities have developed near major waterways for ease of transportation, trading and for connectivity purposes. However, this natural geographic

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advantage is now increasing cities’ vulnerabilities as sea levels rise and storms increase in strength and frequency (World Bank, 2010). Approximately 360 million urban residents live in coastal areas less than 10 meters above sea level with fifteen of the world’s 20 megacities currently at risk from rising sea levels and worsening storm surges (World Bank, 2010). Such geographic vulnerabilities are heightened for poor city residents, who are often concentrated in the most vulnerable areas of the city where the consequences of climate change are most pronounced. Global location also serves as a primer for other climate-linked vulnerabilities. Geography affects agricultural production: tropical locations often have more fragile soil -- due to higher temperatures and intense rainfall – that hampers productivity (Sachs et al., 2001). Heavy dependence on farming in these regions leaves households exposed to greater climatic shocks, such as drought or flooding, on already unstable soil. Health impacts also vary by topography; nations located in tropical zones are more prone to many kinds of infectious diseases, such as malaria (Sachs et al., 2001; Tan & Siri, 2016; Denton, 2002). Compounded with other vulnerabilities, increased health risks are often perpetuated by climate changes impact on resource and service availability. 5.2.3 Rapid urbanization

Urban areas currently hold more than half of the world’s population and most of its built assets and economic activity. However rapid urbanization and growth of large cities in developing countries has led to unequal development and the expansion of highly vulnerable populations living in informal settlements, many of which live on land most exposed to extreme weather events (IPCC, 2014; World Bank, 2010; Mertz et al., 2009; Ravindranath & Sathaye, 2002). Approximately one in seven individuals in the word live in poor quality, overcrowded housing in urban areas, with inadequate provision (or none) of essential services and basic infrastructure (IPCC, 2014). Such instability heightens the health risks and vulnerability to climate change of such groups and depletes the economic resources of the municipality. Particular challenges associated with accommodating larger concentrations of people and activity, including provision of storm water management and efforts to reduce UHI effects, are heightened as concentrated demand for natural resources (water and food), energy and waste management increases in urban areas. As an additional 2 billion dwellers are expected to pour into urban centers over the next three decades, larger numbers of people will be exposed to

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increasingly catastrophic flood and heat events. Given the coastline location of many cities in developing countries, a high concentration of people, businesses, and infrastructure are located in low-lying and unprotected coastal zones and thus more likely to be impacted by sea level rise and storm surge (IPCC, 2014; Mertz et al., 2009). The loss of green space within urban centers and the prevalence of specific demographic groups, including the urban poor, the elderly, and children also present unique climate-linked vulnerabilities, especially in regard to heat hazards. Infants, children, expectant mothers, older age groups, and people which chronic diseases are more likely to be exposed to and impacted by rising temperatures, leading to increased risks of illnesses and mortality (IPCC, 2014;). Avoidance of such climate-related health risks is difficult for low income groups in cities in developing countries, as many lack the access to vital services (such as healthcare and air conditioning). 5.2.4 Preexisting water struggles

Climate change is projected to reduce renewable sources of surface water and groundwater in most dry subtropical regions, intensifying competition for water among agriculture, ecosystems, settlements, industry and energy production (IPCC, 2014; Ravindranath & Sathaye, 2002). Such competition is not only likely to deplete already scant resources at a faster rate but also affect a region’s water, energy, and food security. As the world’s population has increased nearly four- fold in the past century, demand for water has as well. Water consumption for agriculture, industrial and municipal use has risen by five, eighteen, and ten percent, respectively (Makarigakis & Jimenez-Cisneros, 2019). Heightened demand has also led to severe water stress, particularly in Africa and Asia. Already 450 million people in 29 countries are already coping with severe water shortages and this is projected to rise to as much as two-thirds of the world population by 2025 (Makarigakis & Jimenez-Cisneros, 2019). Humans demand for and interaction with preexisting water sources has also altered its quality. Warming temperatures, increases in sediment and pollution loads due to urbanization and heavy rainfall, and reduced dilution of pollutants during droughts reduces raw water quality, compromising the health of city residents even with conventional treatment (IPCC, 2014; Jimenez-Cisneros, 2019; Denton, 2002). Water scarcity driven by urbanization and climate variation also has severe political implications, especially in water-scarce regions like the Middle East and North Africa (Owens, 2018). Conflict over resource availability and jurisdiction can ignite already sensitive situations, leading to civil conflicts within and between water sensitive nations.

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5.3 Vulnerability of cities in developing countries to UHI

The academic literature on identification of specific vulnerabilities of cities to UHI is minimal, especially in the realm of ineffective governance, lack of critical infrastructure, and potential implications of water contamination. However, several of the reasons cities in developing areas are more vulnerable to climate change identified above can be applied within the lens of vulnerability to UHI as well. Such vulnerabilities include disadvantageous geographic location, economic dependence on weather-variable industries, and rapid urbanization and loss of green space. The disadvantageous geographic location of many cities in developing countries plays a critical role in determining their vulnerability to UHI. Considering a widely used indicator of prosperity, gross national product (GNP), reveals a vast gap between rich and poor nations. Many of the poorest regions lie in the geographic tropics – defined as the area between the tropic of Cancer and the tropic of Capricorn – while the majority of the wealthier nations exist in the temperate zone (Sachs et al., 2001). Poorer cities are more likely to be located in this land-locked tropical zone, with a combination of preexisting background climate and rapid urbanization contributing to their propensity to suffer from UHI (Sachs et al., 2001; Manoli et al., 2019). Unlike drier regions, humid climates (like those primarily found near the global Equator) are less efficient at dissipating heat from urban land due to lack of vegetation and aerodynamic smoothness in urban areas (Manoli et al., 2019). Measured in terms of aerodynamic efficiency, this reduces tropical cities convection effectiveness by 58% (Manoli et al., 2019). A cities’ inability to regulate heat not only increases thermal discomfort among its residents but can have serious economic and productivity implications as well. Rising temperatures stemming from UHI can have severe economic consequences, especially for developing nations. Despite economic diversification efforts, many cities in developing areas are still heavily reliant on agriculture and industrial production as means of financial sustainment. Increases in temperature are linked to lower per capita output in countries with above average annual temperatures and can manifest through several channels including lower agricultural output, depressed labor productivity in sectors more exposed to weather, reduced capital accumulation, and poorer human health (IMF, 2017).As climate change continues to intensify heat waves and lengthen warmer months, economic losses in cities in developing areas are expected to grow exponentially. Research also supports the notion that

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temperature shocks disproportionally impact developing countries, with a 1-degree Celsius increase in a given year reducing economic productivity in poorer nations by 1.3% on average (Dell et al., 2012). Higher temperatures may also reduce future labor supply in economically vulnerable nations due to their influence on infant mortality rates. A 1% increase in temperature raises infant mortality rate by 0.12% with the effect growing as lower incomes and food insecurity linked to weather shocks are exacerbated (IMF, 2017). Given that many cities in developing nations economies are tied to industrial output, increasing temperatures will not only compromise a nation’s labor supply and its individual workers productivity but the region’s economic health at large. Outside of a host of economic drawbacks, rising temperatures are also exacerbated by burgeoning urban populations and diminished green space which can present severe public health risks to those living and working in developing nations. Growing populations within cities in developing countries impact their vulnerability to UHI in several ways. As urban centers expand due to demand for housing and employment, the nature of the physical landscape is altered as different building materials are used, heat storage and evapotranspiration capacity are altered, and human activity and energy consumption increase (Manoli et al., 2019; Ravindranath & Sathaye, 2002). The urban fabric of cities in developing countries is altered as development becomes denser. Compact high-rise buildings release less heat than their low-rise counterparts thus modifying the reflectivity and emissivity of urban surfaces as well as its aerodynamic roughness (Manoli et al., 2019). In rapidly expanding cities, UHI intensity is projected to increase 0.043°C when building development increases by one square kilometer (Qiu et al., 2017). Greater population pressure on cities in developing areas also leads to a loss of green space, a critical component in determining the cooling capacity of urban spaces (Qiu et al., 2017; Govindarajulu, 2014). Elimination of the cooling effect of green spaces also has implications for the health of urban residents in developing countries. Research has linked urban heat island effect to 30% of total mortalities resulting from heat in major urban cities (Dang et al., 2018). This finding, coupled with the discovery that every 1-kilometer increase in green space per 1000 people can prevent 7.4 heat related deaths speaks to the powerful influence urban greenery has on regulating urban thermal temperatures and improving public health outcomes (Dang et al., 2018). While such public health risks can affect anyone living within urban boundaries, there is evidence that “vegetated and therefore cooler

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neighborhoods are home to more affluent populations” and that “heat related health risks are lower in those areas” (Heaviside et al., 2017). Such trends are particularly notable in cities in developing countries. Often concentrated in the city’s urban core, surface temperature has been found to be statistically higher in areas characterized by poverty, ethnic minority groups, lack of education and increased crime due to high population density and consequently dense concentration of man-made surfaces (Heaviside et al., 2017). Given rapid rates of urbanization in the developing world, poorer populations tend to congregate in urban cores that lack both proper cooling mechanisms and access to proper healthcare facilities and thus heighten their vulnerability to heat related health risks (IPCC, 2014; World Bank, 2013). 5.4 Most vulnerable global regions to climate change and UHI

Specific academic literature identifying the most vulnerable global cities to UHI is notably sparse. While a number of studies use a case-study based approach that identifies potential UHI vulnerabilities and temperature differences within specific cities in developing countries, as listed in Table 4 (Aflaki et al., 2017; Elsayed, 2012; Emmanuel & Johansson, 2006; Feyisa et al., 2014; Sodoudi et al., 2014; Thundiyil, 2003), a comprehensive identification of the most vulnerable urban areas and associated heat risks is lacking in the literature. Nonetheless, the literature does identify global regions that have been, or are projected to be, disproportionally impacted by rising global temperatures. By extension, these regions will also be most vulnerable to UHI impacts in towns and cities in those regions. Three target regions emerge as areas of focus: West and Sub-Saharan Africa, South Asia, and South East Asia (World Bank, 2013; IPCC, 2014; US AID, 2017). 5.4.1 West and Sub-Saharan Africa

Sub-Saharan Africa is a rapidly developing region of over 800 million people, with 49 countries and a host of diverse ecological, climatic, and cultural features (World Bank, 2013). If projections for a 4°C global warming by the end of the century manifest, sea level in the region is projected to rise up to 100 cm, droughts in central and southern Africa are likely to worsen, and heat extremes are expected to impact increasing proportions of the region (World Bank, 2013). Rising temperatures will exert pressure on ecosystems and key industries in the region, with severe repercussions for the human populations dependent on them. Areas at risk include agricultural crop production, pastoral and livestock systems, food security, and poverty

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mitigation efforts (World Bank, 2013; IPCC, 2014;). In regard to crop production, high temperature sensitivity of several critical crops, including maize, wheat, and sorghum can lead to a significant reduction in crop yields; it is projected that under a 1.5 to 2°C temperature increase, yields losses could amount to 5% with estimations rising to 15-20% under a 3 to 4°C temperature increase projection (World Bank, 2013; IPCC, 2014;). Livestock production is also expected to suffer due to impacts on forage availability and heat stress. West African nations, particularly those located in the Sahel region (a belt of land located between the Sahara Desert to the north and tropical deserts to the south) are also extremely vulnerable to temperature fluctuations. Already one of the poorest and most environmentally degraded regions in the world, the area’s propensity for drought and desertification coupled with a heavy dependence on substance agriculture for sustainment has already left many of its residents at risk (Ministry of Foreign Affairs of Netherlands, 2018). Projected decreases in rainfall and increases in temperature will act as threat multipliers in the regions, aggravating pre-existing vulnerabilities including food insecurity and political instability. As observed, physical vulnerabilities to climate change can worsen pre-existing socio- economic conditions including food insecurity and poverty. Poverty in both African regions is anticipated to grow as poor households with climate sensitive sources of income and food security, such as agriculture, are disproportionally affected by climate change and rising temperatures (World Bank, 2013; IPCC, 2014; Ministry of Foreign Affairs of Netherlands, 2018). Projected losses in crop yields and adverse effects on food production that result in lower incomes will exacerbate poor health conditions and malnutrition, especially in children. Existing and projected urbanization is anticipated to accelerate by stresses stemming from hotter temperatures; as agriculture becomes less viable, migration into urban areas may provide new livelihood opportunities. This only compounds many of the vulnerabilities associated to urbanization and climate change, including overcrowding, inadequate access to water, sewage, and drainage facilities, transmission of vector borne diseases, and UHI (US AID, 2017). In the Sahel, the political fragility of the states makes them more vulnerable to climate change, as extreme weather events and hotter temperatures result in livelihood insecurity and migration, which fuels increased resource competition in urban areas, and drives up food prices (US AID, 2017).

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5.4.2 South-East Asia

South East Asia refers to a region comprised of 12 countries, including Thailand, Vietnam, the Philippines, and Indonesia, with a population of roughly 590 million people (World Bank, 2013). Projected temperature increase in the region is expected to impact tourism and fisheries-based livelihoods and decrease agricultural production in the delta regions due to warming waters. Increasing temperatures are less likely to drastically shift the daytime temperature of much of Southeast Asia, as the climate is more strongly influenced by sea-surface temperatures, however tropical portions of Southeast Asia will become more vulnerable to heat extremes (World Bank, 2013). The prospect of a 2°C warming scenario increases the propensity of unusual heat extremes to cover nearly 60-70% of the land area, with a 4°C increase affecting nearly 90% of the land area in summer months (World Bank, 2013). Extended periods of heat, both in rural and urban settings, is also projected to increase from 45 to 90 days a year to around 300 days for a 4°C world (World Bank, 2013). While many of the regions climate vulnerabilities stem from sea level rise and coastal erosion, high rates of urban population growth in the region’s major cities will also impact the severity and extent of warmer temperatures and UHI. The effect of heat extremes will be particularly pronounced in urban areas due to UHI, caused by increasing population (and consequently energy) pressure on cities as well as urban centers’ growth in size and density. This will result in greater health problems and higher mortality rates in urban areas as compared to their rural counterparts (World Bank, 2013). Economic vitality is also likely to be impacted as much of the national production of the region is also concentrated in South East Asia’s cities (World Bank, 2013). It has been estimated, for example, that metro Manila’s GDP, at 49% ($149 billion) represents a large share of the Philippines $305 billion GDP (World Bank, 2013; Hawksworth et al., 2009). As observed, UHI and heat extremes decrease the economic strength of urban areas by reducing worker productivity and production rates. In South East Asian cities, this could have broad implications for costal economies whose GDPs are expected to double or quadruple from the present day. Rising heat is also expected to worsen health problems in vulnerable demographics, including women and elderly population. Per demographic observations, South East Asia’s populations are aging rapidly; in Vietnam, the percentage of people aged 60 and up is projected to increase by 22% between 2011 and 2050 and account for nearly 31% of the nation’s total population (World Bank, 2013; United Nations Department of Economic and Social Affairs, 2013). Such increases

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in the proportion of older people place larger numbers of people at higher risk of the effects of heat extremes. 5.4.3 South Asia

South Asia is comprised of 7 nations (most notably India, Bangladesh, and Sri Lanka) and a burgeoning population that is anticipated to reach 2.2 billion by 2050 (World Bank, 2013). Global increases in temperature are projected to negatively impact sea level rise, glacier melting and snow loss, and incidents of prolonged, extreme heat. Agriculture production is also likely to suffer due to unstable water sources, prolonged periods of drought, and rising temperatures. The rapid growth of many the region’s cities, most notably in India, also make urban populations especially vulnerable to heat extremes, flooding, and disease (World Bank, 2013). Projected global temperature increases by 2°C and 4°C are projected to warm the region by 2°C and 3 to 6°C, respectively. A consistent pattern of warming temperatures is likely to aggravate heat extremes that are largely absent in today’s climate, with countries including Sri Lanka and Bhutan experiencing unprecedented heat during more than half of the summer months (World Bank, 2013). Many of regions primary crops, including rice and wheat, are highly sensitive to temperature variations. As temperatures continue to rise, rice and wheat yields are anticipated to decline 8% for every 1°C increase in average growing season temperatures (World Bank, 2013; Lobell et al., 2011). Reduced crop yields can lead to greater food insecurity and livelihood instability, driving migrants into already overpopulated and under-served city centers. Such is the case with many of India’s major cities, most notably Delhi and Mumbai, who are quickly becoming the region’s most notable urban heat islands (Vidal & Pathak, 2016). Two of the fastest growing global cities, Delhi and Mumbai, are anticipated to become some of the world’s most populous urban agglomerations. The population of Delhi is currently 29 million residents with projected growth to 37.2 million people by 2028 (Sharma, 2019). While not quite as large, Mumbai currently has 18.4 million residents with a population density of 76,790 people per square mile (Kolb, 2019). With rapid urbanization rates testing the limits of both cities developmental threshold, as both cities have nearly doubled in size and population over the past 25 years, land use patterns have continued to shift to meet rising demand (Vidal & Pathak, 2016). Over the past forty years, Delhi has increased its built environment by 30.6%, while cultivated areas and dense forest have decreased by 22.8% and 5.3%, respectively (Chandra, 2019). In the same time span, Mumbai has become almost entirely paved and

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concretized. Such expansive development has led the two cities to be deemed the nation’s first “urban heat islands” with significantly different climates as compared to their surrounding rural areas. Temperatures in both Delhi and Mumbai have risen by 2 to 3 °C in the past 15 years, with the cities averaging temperatures 5 to 7 degrees warmer than surrounding areas on summer nights (Vidal & Pathak, 2016). Steadily increasing temperatures coupled with the looming threat of climate change increases the cities vulnerability to climate shocks such as intense heat waves, which are anticipated to breach survivability threshold by the end of the century (Chandra, 2019). Given that the current threshold is a temperature of 35 °C, in which a few hours of exposure can cause death in even the healthiest individual, movement beyond that point spells trouble for India’s most vulnerable populations including those living in informal settlements and the homeless population (Chandra, 2019).

6.0 UHI mitigation strategies 6.1 Introduction

Just as understanding the causes and consequences of UHI is important, so too is assessing the various mitigation strategies developed to lessen it. Though these approaches have already been implemented in various forms and with varying levels of success in cities across the globe, this section seeks to compile a comprehensive list of the major UHI mitigation strategies identified in the literature. Many of these strategies involve land use changes or modifications, while several more require alteration of physical structures. Not limited to cities in developed nations, several of these strategies can also be implemented in developing countries.

6.2 Review of major UHI mitigation strategies

In order to best assess potential mitigation strategies for cities in developing areas, it is important to first explore the application and associated costs of existing UHI mitigation strategies. As listed in Table 3, these approaches include improvement of trees and vegetation, urban green spaces, green roofs, vertical greening, use of cool building materials, cool roofs, cool pavements, enforcement of heat island reduction policies, and modification of urban form.

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6.2.1 Trees and vegetation

It is well understood that shade trees and smaller plants such as shrubs, vines, grasses, and ground cover help cool metropolitan environments (U.S. Environmental Protection Agency, 2008). However, rapid urbanization in cities has effectively reduced or eliminated much of the green space available within municipal limits and perpetuated environmental phenomena such as UHI. Yet, just as the removal of trees and vegetation can increase urban temperatures, increasing vegetative cover can cool it just as efficiently. Inclusion of trees and vegetation as a pertinent mitigation strategy against UHI stems from the three primary benefits such organisms provide: 1) shading, 2) evapotranspiration and 3) alteration of the movement of air (U.S. Environmental Protection Agency, 2008; Block et al., 2012; Nuruzzaman, 2015). More pronounced urban canopies limit the amount of solar radiation that reaches the surface, shading surrounding heat-absorbing materials (Block et al., 2012). Such shade reduces surface and ambient temperatures below the tree canopy and heat gain to buildings and other infrastructure (U.S. Environmental Protection Agency, 2008; Block et al., 2012). This in turn reduces buildings dependence on air conditioning and improves overall air quality (Nuruzzaman, 2015). Additionally, trees and vegetation improve human thermal comfort by providing both direct shading and reduction of solar radiation reflected from the ground and building surfaces. The quality of the shade provided is determined by factors such as placement, canopy height and architecture, and leaf size and structure (Block et al., 2012). Trees that have a larger leaf area index (LAI), including those with multiple layers of foliage cover and thick, large leaves are more likely to effectively reduce incoming solar radiation (Block et al., 2012). Evapotranspiration also plays an important role in cooling urban temperatures as the absorption and release of water vapor from vegetation increases humidity and decreases air temperature (U.S. Environmental Protection Agency, 2008; Ballinas & Barradas, 2016). Evapotranspiration, alone or in combination with shading, can have a significant impact on the reduction of urban air temperatures. Numerous studies have measured various reductions, including that peak air temperatures can be up to 4°C cooler in well-planted areas in a city as compared to its urban core and that urban greenery can effectively cool surfaces by up to 20°C if implemented effectively (Tan et al., 2016; Armson et al., 2012). Trees and other large vegetation can also act as windbreaks or windshields to reduce the wind speed in the vicinity of buildings (U.S.

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Environmental Protection Agency, 2008; Block et al., 2012). While this is beneficial during the winter months in reducing the ‘windchill factor’, its impacts may be less appreciated during the summer as it could potentially obstruct cooling breezes. The use of trees and vegetation in reducing UHI is most impactful when planted in strategic locations around buildings (U.S. Environmental Protection Agency, 2008). Operating within the understanding that heat is transferred into buildings through several mechanisms including direct gain through windows and conduction through opaque wall and roof surfaces, trees should be placed with consideration of not only roof shade but also of wall and window shade, especially during the summer months when solar radiation levels are high (Block et al., 2012). Research supports findings that planting deciduous species (i.e. oak, maple, birch) to the west is typically most effective in cooling a building, especially if the trees shade the structures windows or part of the building’s roof (U.S. Environmental Protection Agency, 2008; Block et al., 2012). Such strategic shading also reduces air conditioning demand. Planting trees to the south of buildings can have both positive and negative drawbacks. While it is effective in reducing summertime energy demand, depending on the location and height of the building the trees can also increase energy demands during the winter by blocking useful solar energy when the sun is low in the sky (U.S. Environmental Protection Agency, 2008). In extremely dense urban areas, where trees either do not fit or grow too slowly vines may prove to be a more effective solution (U.S. Environmental Protection Agency, 2008). Vines require less soil and space and grow very quickly; while they do not provide the same rates of evapotranspiration, they will shade exterior walls and reduce surface temperatures (U.S. Environmental Protection Agency, 2008). Consideration of a city’s climatic zone is also crucial when assessing the amount and type of energy saving and cooling associated with specific trees and bushes (Block et al., 2012; Ballinas & Barradas, 2016). Variation in vegetation type, size and water status based on preexisting climatic conditions must be taken into account to determine best planting approaches. In warm or hot climates (particularly in the southern hemisphere), it is best to provide shade to roofing and northern and western walls (Block et al., 2012). In contrast, in cooler climates where energy savings will be less, trees should be planted in the path of prevailing winter wind directions while allowing solar radiation to reach the northern and western walls of a building (Block et al., 2012). Such strategic planting techniques are especially critical for climates with strong winter conditions and/or exposed locations.

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The cost of implementing a citywide tree-planting program varies based on the types of program offered and the trees recommended (Akbari, 2005; U.S. Environmental Protection Agency, 2008). Primary expenses associated with planting and maintain the trees include purchasing materials, initial planting, and ongoing maintenance including pruning, pest control, and irrigation (U.S. Environmental Protection Agency, 2008). Other external costs can also include program administration, root damage, and stump removal. Currently, the most recent research estimates the present value of the life cycle cost of a tree is between $300-500 per tree with nearly 90% of the cost attributed to professional planting, pruning, tree and stump removal (Akbari, 2005; Nuruzzaman, 2015). While the expenditures of planting trees often outweigh the trees fiscal return (given that a tree only generates $200 in savings over its lifetime) the external benefits from expanding urban vegetation outweighs these costs (U.S. Environmental Protection Agency, 2008; Nuruzzaman, 2015). Numerous benefits can be derived from implementing tree-planting programs at the municipal level. In addition to saving energy, the use of trees and vegetation as a mitigation strategy can provide air quality and greenhouse gas benefits as leaves remove various forms of gaseous air pollution through dry deposition and shade trees reduce evaporative emissions from parked vehicles (U.S. Environmental Protection Agency, 2008; Nuruzzaman, 2015). Additionally, trees and vegetation remove and store carbon and minimize greenhouse gas emissions and rising urban temperatures by reducing energy demand (U.S. Environmental Protection Agency, 2008; Nuruzzaman, 2015). The use of shade trees reduces heat gains in buildings, which helps lower indoor air temperatures and consequently health impacts from prolonged heat waves. Adding trees and vegetation can also provide a host of quality-of-life benefits, including reducing urban noise by 3 to 5 decibels (U.S. Environmental Protection Agency, 2008). A well-placed row of trees has also been linked to reduced crime, increased property values, and psychological decreases in stress and aggressive behavior (U.S. Environmental Protection Agency, 2008; Akbari, 2005). Additionally, vegetation can reduce stormwater runoff through interception and absorption of water, thus limiting the potential for flooding and adverse impacts to critical water sources (U.S. Environmental Protection Agency, 2008; Akbari, 2005). 6.2.2 Urban green spaces

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Urban green spaces, often in the form of urban parks, gardens, and sport fields can provide cooling benefits to city residents and the adjacent built environment, especially on calm, clear nights (Block et al., 2012; WHO, 2011; Wong & Yu, 2005; Feyisa et al., 2014). While observational research varies, parks are observed to be 1 to 3°C cooler than the surrounding urban landscape with the ‘greatest zone of influence’ existing downwind from the park (Block et al., 2012; Wong & Yu, 2005). Peak temperature differences are often noted at midday in summer months, with ambient temperature differences reaching up to 3-4°C (Block et al., 2012; Feyisa et al., 2014). However, population growth and high demand for housing has led to the conversion of green spaces in rapidly urbanizing cities, eliminating a critical cooling component and aggravating the UHI effect. Reintroduction and promotion of urban green space as a UHI mitigation strategy is particularly beneficial both for the cooling effect it provides as well as its implications for improved health and quality of life among urban dwellers. Several important considerations to include in the implementation of urban green spaces is the size, shape, species, and canopy cover of the park (Feyisa et al., 2014; Block et al., 2012; Park et al., 2017). Research indicates that the inclusion of a series of smaller parks integrated throughout the urban built landscape provides more effective cooling to surrounding areas than one large park (Block et al., 2012; Park et al., 2017). Small green spaces are more efficient in reducing the air temperature of the urban block on which they belong, especially if they are constructed in a polygonal or mixed (combination of polygonal and linear form) shape (Park et al., 2017; Feyisa et al., 2014). Large parks are generally cooler; parks must generally exceed 2 hectares before a significant temperature difference is developed with the surrounding urban landscape (Block et al., 2012). The inclusion of climate appropriate species as well as the density and distribution of trees within green spaces also influence intensity of cooling provided (Block et al., 2012; Feyisa et al., 2014). Large parks with high rates of canopy cover will see the greatest cooling benefits during the day (particularly in the afternoon) while larger parks with fewer trees will provide the greatest cooling benefits within the park and downwind at night, due to uninhibited radiation loss (Block et al., 2012). Availability of urban green spaces also reduces heat stress and air pollution while providing a space for physical activity and active movement, improving both the physical and mental health of city residents (WHO, 2011). Strategic placement of green spaces is also critical in assisting groups most vulnerable to heat stress, including the elderly and low-income populations.

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Consequently, planners should consider placing aged care facilities, hospitals, and public housing close to parks and related green environments (Block et al., 2012). Inclusion of such considerations, as well as the expansion of urban green spaces at large, has been linked to diminishing mortality rates in urbanizing cities as well. Focusing specifically on heat-related mortality in Vietnam, researchers found that the while urban heat island effect was directly attributable to 42% of the total mortalities resulting from heat in Ho Chi Minh City, every increase in green space of a square kilometer per 1000 people prevented 7.4 heat related deaths (Dang et al., 2018). Psychological health and social benefits have also been linked to urban green spaces, including alleviation of stress and anxiety, improved mood and attention and reduction in social isolation (especially for elderly populations) (Lee et al., 2015). While urban green spaces provide a host of environmental, social, and health benefits and play a critical role in reducing urban temperatures, further research must be conducted to calculate the costs of urban green space (Lee et al., 2015). Quantifying utility versus costs for green spaces is challenging due to its multiplicity of its uses as well as attributable benefits. Careful consideration on the part of urban planners and policy makers must be given in deriving specific benefits and costs of urban green spaces based on city-specific contexts. 6.2.3 Green roofs

Given that roofs compose about 21 to 26% of a city’s total surface area, it is natural to assume that these arrangements can play a critical role in reducing UHI (Wong, 2005). With roots in Mediterranean architecture, green roofs are an emerging technology that can help communities combat rising urban temperatures as vegetation on a green roof shades surfaces and removes heat from the air through the evapotranspiration (EPA, 2008; Lehmann, 2014). Unlike traditional roofs, which can exceed ambient air temperatures by up to 50 °C, the surface of green roofs is often cooler than the ambient air around it (Liu & Baskaran, 2003). Although design considers variably, green roofs are generally composed of four layers: a base layer comprised of a waterproof barrier to protect the building; a drainage layer to store and direct runoff; a soil or growth medium layer and a plant layer (GSA, 2011; Lehmann, 2014). Adaptable to several structures, these roofs are feasible solutions for multi-story buildings, single family residences, commercial and public buildings. Green roofs ability to cool the microclimate around it by shading heat absorbing materials, increasing albedo and providing evapotranspirative cooling not only improves thermal comfort within and around buildings but minimizes energy demands for

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summer cooling and winter heating (Block et al., 2012; Gago et al., 2013). In addition, green roofs use their vegetated surfaces to absorb and store rainfall, reducing stormwater runoff from individual buildings (Block et al., 2012). However, the feasibility and effectiveness of green roofs is largely dependent on its design and installation and vary according to their characteristics. Green roofs are often subcategorized into two main types: extensive green roofs and intensive green roofs (EPA, 2008; Block et al., 2012; GSA, 2011). Extensive roofs are relatively inexpensive to install and often follow a simpler, lighter weight design. The broader idea behind this variation is to design a roof that requires minimal maintenance or human intervention once it is installed. Plant selections typically include more hardy, alpine-like groundcover and those adapted to more extreme climates such as moss and other small plants (EPA, 2008; Block et al., 2012). These plants only require a thin layer of soil and minimal irrigation, minimizing the amount of added structural support needed when retrofitting an existing building and boosting its cost-effectiveness (GSA, 2011). However, given that many extensive green roofs are left to grow on their own and often act as a ‘climatic skin’, quantifying the thermal benefits derived from them is harder to assess (Kohler et al., 2002). Despite this, their inexpensive upfront and long- term costs make them the more popular choice for green roofs across the globe. Intensive green roofs are similar to conventional parks and green spaces and are often installed by building managers as a means to both save energy and provide a garden space for building residents and the general public to enjoy. Unlike extensive roofs, whose shallow soil limits the plant variations available, there is almost no limit on the type of available plants and can even include large trees and shrubs (EPA, 2008). In order to support a broader variety of greenery, intensive roofs are often heavier and require substantial structural support to accommodate the weight of thicker soil and public use. Installation of these roofs is often capital intensive and requires more maintenance over the long term than extensive roofs (GSA, 2011). Thermal benefits of intensive green roofs are easier to quantify, as many are considered to have similar microclimate benefits as urban parks or gardens (Block et al., 2012). Despite the type chosen, green roofs provide communities with a host of environmental, social, and health benefits. Since many green roofs function in a similar manner to ground level green spaces or urban parks, similar benefits are provided by these spaces. Benefits stemming from the installation of green roofs include reduced energy use, reduced air pollution and greenhouse gas emissions,

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enhanced stormwater management capabilities, improved human health, enhanced quality of life and increased urban biodiversity (EPA, 2008; GSA, 2011; Perini et al., 2011). Green roofs can save energy needed for heating and cooling purposes; when green roofs are wet, they absorb and store large amounts of heat thus reducing extreme temperature fluctuations. Dry green roofs act as an insulator, decreasing the flow of heat through the building and reducing the cooling energy needed to stabilize interior temperatures (EPA, 2008). Most of the energy savings attributed to green roofs occur in the summer months when reduced roof surface and ambient air temperatures minimize energy demands for summer cooling by up to 58% (Block et al., 2012). Energy savings are also highest for structures with high roof-to-wall ratios, including low-rise warehouses, factories, and shopping centers. As previously explored, vegetation on green roofs removes air pollutants and greenhouse gases from the atmosphere through the processes of dry deposition and carbon storage. Green roofs also slow the formation of ground level ozone by lowering ambient and surface temperatures and minimizing energy-linked air pollution (EPA, 2008). Another key benefit of green roofs is their ability to reduce and slow stormwater runoff into the urban environment. The presence of plants and growing medium absorbs much of the water that would turn into runoff, not only reducing the volume of water flowing into municipal sewer systems but prohibiting it from bringing pollutants to critical bodies of water (GSA, 2011). Stormwater capabilities vary by roof design, with intensive green roofs (and associated thicker soil) capturing more rainfall than extensive green roofs (EPA, 2008). Additionally, green roofs contribution to reduction in temperatures both within and around a building can improve human comfort and minimize the risk of heat-related stressors. Allowing public access to green roofs improves city resident’s quality of life by providing access to green space for refuge and relaxation, thus reducing stress and improving worker productivity (GSA, 2011; EPA, 2008). Finally, green roofs can provide new habitats for plants and animals, boosting biodiversity in urban areas. Many attract new species of birds and invertebrates; given intensive roofs wide selection of plant species, they are more likely to support greater diversity than extensive roofs (GSA, 2011). However, despite these many benefits several cost considerations must be assessed before pursuing green roofs as a viable strategy. While several positive economic benefits can be derived from the installation of green roofs including lower energy and stormwater management costs and less frequent roof replacements, green roofs often present more upfront costs than most conventional and cool roof technologies

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(EPA, 2008; GSA, 2011). Installation costs vary depending on the design of the roof and components used; extensive roofs often start at $10/ square foot and $25/ square foot for intensive roofs (Peck & Callaghan, 1999). Outside of initial construction costs, long term maintenance costs for plant upkeep and irrigation systems must also be considered. Again, costs vary across roof types as both intensive and extensive roofs can cost up to $1.50 per square foot in maintenance, however maintenance for extensive roofs decline as plants begin to cover the entire roof (EPA, 2008). While these costs appear high, green roofs tend to have a longer life cycle than traditional roofs, with a life expectancy’s of around 40 years as compared to 17 for a traditional roof (GSA, 2011). Many of the aforementioned benefits justify the cost in densely populated areas, as savings derived from stormwater, energy, carbon dioxide elimination, and community engagement more than make up for the increased cost of installing and maintaining green roofs. 6.2.4 Vertical greening; vegetated facades and walls

The concept of green façades has long been a favored approach among architects and landscape planners but it was not until the 1980s that they began to incorporate them deliberately into building design to provide shade and evapotranspiration cooling (Block et al., 2012). Vertical greening systems (VGS), also known as vertical gardens or green-wall technologies, consist of vertical structures of vegetation that can be attached to a building façade or interior wall (Pérez-Urrestarazu et al., 2015). While vertical greening systems can range from simple structures to complex designs, these structures are generally divided into two broad categories: green facades and living walls (Pérez-Urrestarazu et al., 2015; Block et al., 2012; Price et al., 2015). Green facades are primarily formed by climbing plants or cascading groundcover that is rooted at the base in the ground or in plant boxes; plants suitable for such use are primarily self- clinging climbers that have adventitious roots, suckers, or thorns (Block et al., 2012). Due to the lower diversity and density of plants, green facades generally require less intensive maintenance and protection than living walls. Living walls are a more complex solution that involves a supporting structure with different attachment methods (Pérez-Urrestarazu et al., 2015). Unlike green facades, living walls are not rooted at the base. Instead, the wall is constructed using cloth or felt panels containing a light weight growing medium and plants are watered using a hydroponic system of irrigation. (Block et al., 2012; Price et al., 2015). Based on the materials used, living walls can support a wide variety of plant species including ferns, shrubs, and even

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edible herbs and vegetables. While living walls have traditionally acted as ‘passive’ biofilters, new technology has promoted the integration of such walls into building’s air conditioning and ventilation systems (Pérez-Urrestarazu et al., 2015). Known as an ‘active living wall’, the structures air flow is forced to pass through the green wall with the recycled fresh air resupplied to the building’s interior spaces. However unlike green facades, living walls are more expensive to implement and maintain. Despite this, these two variations of vertical greening remain a promising strategy for reducing urban temperatures. Vertical greening, through the use of vegetated facades and living walls has the potential to become an important component of green infrastructure in cities as well as a vital mitigation strategy in combatting UHI. Unlike buildings roofs, walls tend to be less insulated and therefore unable to retain cooler and/or warmer temperatures. Vegetated greening can reduce such variability through provision of thermal insulation and reduction of internal temperatures in buildings (Block et al., 2012). While vertical greening offers less of a substantiated impact than green roofs, its location closer to surface level can improve pedestrians’ thermal comfort by shading heat-absorbing concrete (Block et al., 2012). In conjunction with increased thermal comfort, vertical greening also provides a host of environmental and ecological benefits. Green facades and living walls assist in reducing city structures energy consumption (one of the critical ways to reduce UHI) through four primary mechanisms: interception of solar radiation through vegetation, thermal insulation provided by vegetation, evaporative cooling, and modification of wind patterns impacting the structure (Pérez-Urrestarazu et al., 2015; Price et al., 2015; Rahkshanderoo et al., 2015; Perini et al., 2011). These methods not only provide cooler temperatures both within and around city buildings but also assist in minimizing air pollution through reduced demand for energy. Through the process of dry deposition, in which plants absorb pollutants through their leaf stomata, vertical greening can also minimize harmful levels of ozone, nitrate, and carbon monoxide from the urban atmosphere (Price et al., 2015). The reduction in air pollution also reduces many of the health consequences of UHI, namely respiratory conditions (i.e. asthma) and heat linked ailments such as heat cramps, exhaustion, heat stroke and heat related fatalities. Living walls also reduce noise pollution, as the material used has sound-absorbing effects (Pérez-Urrestarazu et al., 2015). Ecologically, the inclusion of diverse plant species within vertical greening systems promotes reconciliation ecology, which aims to modify anthropogenic habitats to support a broader range of plant and animal species

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without compromising land use (Pérez-Urrestarazu et al., 2015). Such green infrastructure creates habitats for plants and animals while also permitting use by humans for space. Additionally, fiscal and environmental costs of implementing urban greening must also be considered when determining the feasibility of such strategies. Key considerations of greening viability include construction and maintenance costs, water consumption, as well as negative aesthetic effects (Rahkshanderoo et al., 2015; Pérez- Urrestarazu et al., 2015). Installation costs for vertical greening systems are often high, as the structures require construction of extensive irrigation systems. The initial building of green surfaces is also costly, with support structures comprising 7 to 10% of overall installation fees (Pérez-Urrestarazu et al., 2015). Long term upkeep of the walls also adds to overall costs, as systematic pruning, weeding, plant species substitution and water pipe replacement is necessary to maintain the feasibility and effectiveness of vertical greening strategies (Rahkshanderoo et al., 2015). The extent of irrigation measures needed to support green facades and living walls varies depending on the air temperature and humidity of the surrounding environment, incoming solar energy, speed of air flow, and vegetation type (Pérez-Urrestarazu et al., 2015). While careful consideration of such factors can minimize the systems water consumption, high rates of water waste still remain a challenge among vertical greening systems. Inclusion of water storage tanks for rainfall capture and/ or irrigation water recycling can diminish such waste, at the cost of increased capital expenditures. Finally, the aesthetic value of living walls and green facades is largely determined by initial design and species selection. Plants mortality rate must be a key consideration when choosing which organisms to include as it not only impacts the aesthetic value of the wall but cost of replacement as well. Such rates vary depending on system and location; however, if not considered it can reach up to 50% annually (Pérez-Urrestarazu et al., 2015). A constant need to replace the plants thus drives up long term maintenance costs of the greening systems. Despite these aforementioned costs, vertical greening systems still remains an economically viable solution when the benefits listed above are considered. 6.2.5 Building materials

Materials used in the urban context play an important role in determining a city’s thermal balance as they absorb solar and infrared radiation and dissipate accumulated heat through convection and radiative processes (Akbari et al., 2016). As emphasized in the proceeding cool roofs and cool pavements sections, the use of ‘cool’ materials on buildings and structures is

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crucial in reducing UHI within cities. Inclusion of such materials is often a more feasible strategy than the development of green roofs or vertical greening structures due to its efficiency, relatively low-cost, and easy to apply solutions (Synnefa et al., 2008). Cool materials are characterized by their ability to reflect a significant amount of solar radiation and dissipate heat absorbed through radiation. This not only contributes to increasing urban albedo but also maintains lower surface temperatures, a critical factor in mitigating heat islands within cities (Synnefa et al., 2008). Growing concern over rising urban temperatures and the role cool materials can play in addressing such worries has led to the development of innovative materials and techniques in recent years. A clean, smooth, white surface most strongly reflect solar and near-infrared (NIR) radiation, achieving a solar reflectance of approximately 85% and is the coolest type of roofing or paving surface available (Akbari et al., 2016). Most bright white materials achieve their high reflectance from the use of titanium dioxide within the mixture, a pigment that reflects nearly all of sun’s wavelengths. Research also supports the use of lime, another variation traditionally knows for its whiteness, as a cool coating for the external surfaces of buildings and concrete pavement (Santamouris et al., 2008). Modification of existing materials with cooler technologies is also possible; white or light-colored coating can be added to traditional roofing materials, single ply materials, tiles and metals to convert them to cooler options. Cool white clay tiles have been created using traditional ceramic materials with the added inclusion of a white gloss glaze; a white topcoat is often added to create cool, white shingles (Gartland, 2008). While not quite as effective as smooth, white surfaces, the use of aluminum is also being explored as a possible resource for UHI mitigation. Aluminum coatings enhance solar reflectance to above 50% for most reflective coatings; however, this is often offset by its lower infrared emittance (Akbari et al., 2016). In order to avoid issues associated with glare on all-white surfaces while still maintaining surface aesthetic, the development of coatings in a variety of colors that still maintain high levels of solar reflectance have also been developed. The creation of roofing materials that are directionally reflective, in which the color and reflectance of the material shift depending on the direction of solar radiation is also commercially available for use (Akbari et al., 2016). Utilization of such materials for cool roofs would be beneficial in climates with varying seasons; it can reflect sunlight during the summer and absorb heat during the winter.

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6.2.6 Cool roofs

Given that one source of urban heat islands is the combined heat from numerous individual hot roofs across a city, the concept of cool roofs provides a much-needed alternative to address such problems. Unlike traditional roofs, which can reach peak summer temperatures of 55-85 °C (150 to 185 °F), cool roofs can remain 28 to 33°C cooler than traditional materials (Konopacki et al., 1998). Composed of highly reflective and emissive material, cool roofs lower both their surface temperatures and the ambient air around them through two primary properties: solar reflectance and thermal emittance (EPA, 2008). Unlike traditional roofing material which reflects only 5 to 15% of solar energy received, cool roofing can have a solar reflectance of more than 65%, absorbing less than 40% of the energy that reaches it (EPA, 2008). Cool roofs also have higher thermal emittance, giving off heat more readily to reach thermal equilibrium at lower temperatures. While impacting the surrounding environment in similar ways, cool roofs can generally be categorized into two variations: low-sloped and steep-sloped. Low-sloped roofs are typically flat, with only enough incline to provide drainage, and are found on the majority of commercial, industrial, office, and multi-family buildings. Steep slopes generally have a steeper pitch and are traditionally found on retail commercial buildings and residences (EPA, 2008). Depending on the slope of the roof, the requirements for material and installation differ. Traditionally, low-slope cool roofs use built up roofing and coatings or single- ply membranes to upgrade its cooling capabilities. Coatings are best applied to preexisting low- sloped roofs in good condition. Exhibiting a similar consistency to thick paint, coating can be applied to a wide range of existing surfaces, including asphalt and metal (EPA, 2008). Single-ply membranes come in sheets that are applied in a single layer to the roof before being sealed by glue or hot-welding. Unlike coatings, which are typically used if an existing roof needs moderate repair, single-ply membranes are used for more extensive repairs. While low-sloped cool roofs remain the favored option, cool roof options for steep-sloped roofs are also available. Most focus on modifying existing product, including tiles and painted metal roofing (EPA, 2008). The introduction of “cool colored” tiles can increase a steep-sloped roofs solar reflectance by up to 70% as the tiles contain pigments that reflect solar energy in the infrared spectrum. Cool colored metal roofing products contain similar pigments and have a longer life cycle and higher durability than their tiled counterparts (EPA, 2008). In general, the use of cool roofs as a mitigation strategy also brings many benefits.

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Several benefits can be derived from the implementation of cool roofs including reduced energy use, increased energy savings, reduced air pollution, improved human health and comfort and longer length of useful life (EPA, 2008; Akbari, 2005). Given that cool roofing transfers less heat to the building below, the structure stays cooler and more comfortable and demands less energy for cooling. While energy savings are sight-specific and depend heavily on insulation levels and duct placement within individual buildings, savings typically range from 46% during non-peak hours and 20% during peak demand (Akbari, 2005). Cool roofs are also likely to save energy when most needed – during peak demand on sunny, hot summer afternoons. By reducing cooling system needs, cool roofs minimize customers peak electrical demand (EPA, 2008). Lower energy demand also improves the city’s air quality and reduces air pollution emissions such as smog. If cool roofs were to be implemented on a broad scale in most major cities, municipalities could see up to $104 million in environmental savings a year (Akbari, 2005). Cool roofs can also substantially improve human health and comfort, especially for those living in buildings without air conditioning as cool roofs can lower ceiling surface temperatures by up to 3°C (4.7°F) (Blasnik, 2004). This can serve as a significant public health benefit during heat waves by reducing the risk for heat-related illness and death. Finally, cool roofs are likely to have longer ‘lives’ as compared to conventional roofs. Unlike darker roofing material, cool roofing material experiences less temperature fluctuation and expansion and/or contraction of material thus improving its longevity (Akbari, 2005). However, despite these benefits cool roofs can have potential adverse impacts and costs that must be considered. While cool roofs high solar reflectance is an asset during hotter months, it can hinder effective warming in cooler months by reflecting necessary solar heat away from the building (EPA, 2008). The widespread implementation of cool roofs and subsequent increase in albedo (reflectiveness) has the potential to create a harmful glare, creating visual discomfort for city residents and potentially harming aviation and flying wildlife (Akbari, 2005). While not as noticeable on low-sloped roofs, serious consideration must be payed to this issue if a city has high volumes of steep-sloped structures. In addition, many types of building materials used in the roofing process, such as tar roofing, are not well suited for painting or coating. While not impossible, it does require more extensive recoating and rewashing that can drive up the expenses of regular maintenance (Akbari, 2005). In regard to cost, initial installation fees and long-term maintenance comprise most of the expense. Cool roof coatings typically cost between

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$0.75 and $1.50 / square foot for both material and labor; single-ply membrane is slightly more expensive at $1.50 to $3.00 / square foot; however, it does not require the same extensive maintenance as coatings (EPA, 2008). In regard to benefit-cost considerations, the benefits are more likely to outweigh the costs if city is located in a warmer climate, the roof accounts for much of the exterior surface area, there are significant problems with maintain indoor comfort, or roof materials tend to crack and age prematurely (EPA, 2008). 6.2.7 Cool pavements

In many urban centers, pavement compromises the largest percentage of land cover, often accounting for 20 to 40% of a city (Qin, 2015). Conventional pavement, which is traditionally comprised of impervious concrete and asphalt, transfers heat downward to be stored in the pavement subsurface. This heat is then re-released at night and acts as a significant contributor to urban heat islands. Cool pavements can be assembled by using existing pavement technologies with modifications or by introducing new materials into conventional practices (Qin, 2015; U.S. Environmental Protection Agency, 2012). Unlike its ‘cool roof’ counterpart, cool pavement lacks a standard, official definition (U.S. Environmental Protection Agency, 2012). Generally, cool pavements raise solar reflectance, enhance evaporation, and reduce heat in the urban atmosphere thus contributing to lower surface temperatures and reductions in the amount of heat stored in pavements (U.S. Environmental Protection Agency, 2012; Qin, 2015). Cool pavements are branded into three categories: reflective pavements, evaporative pavements, and heat-harnessing pavements (Qin, 2015; Lee et al., 2010). Reflective pavements have greater albedo than traditional pavement thus helping decrease surface temperature and sensible heat release. Evaporative pavements hold water at the surface layer or lower layers to facilitate evaporative cooling. Heat-harnessing pavements suppress the surface temperature heat by using the absorbed heat as renewable energy for other uses (Qin, 2015; Lee et al., 2010; U.S. Environmental Protection Agency, 2012). While few studies have measured the role cool pavements play in reducing UHI, research has found that for every 10% increase in solar reflectance pavements could reduce surface temperatures by 4ºC (Pomerantz et al., 2000). Several variations of cool pavements fall under the three aforementioned categories. Not all applications are equally suited for all uses; consideration of traffic rates, costs, and local conditions must be applied when assessing the proper materials to use. In regard to reflective pavements, several modifications of existing materials can be utilized to increase pavements

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albedo. Traditional asphalt pavements, which consist of an asphalt binder mixed with an aggregate, can be modified to include high albedo materials or treated after installation to raise reflectance (U.S. Environmental Protection Agency, 2012; Lee et al., 2010). Inclusion of more reflective components can improve pavements reflectiveness from 4% in its preexisting state to 15 to 20%; modified asphalt can also be used in a host of applications including trails, parking lots, and highways (Wong, 2005; U.S. Environmental Protection Agency, 2012). Using lightly colored aggregates, traditional concrete pavements can be modified as well and white cement reflectivity can be increased by up to 70% (Wong, 2005). Considering that cement is used in a wide range of applications, reflective concrete pavement can be used on trails, roads, and parking lots (U.S. Environmental Protection Agency, 2012). Resin based pavement, which utilize a clear tree resin in leu of ones with petroleum-based elements, is also used to create more reflective surfaces. However, the reflectivity of these pavements is directly dependent on the aggregate used since the resin itself is clear (Lee et al., 2010). While use depends on the pavement application, this alternative pavement strategy is often reserved for low traffic areas including trails and sidewalks (U.S. Environmental Protection Agency, 2012). Chip seals made with high- albedo aggregate, which are used to resurface low-volume asphalt roads, present another viable option for reducing pavement surface temperatures (Qin, 2015). White topping, in which a thick layer of concrete (greater than 4 inches) is laid on top of asphalt surfaces, can boost surfaces reflectivity from 4% to 40% (Lee et al., 2010). This approach is typically used to resurface road segments, intersections, and parking lots. Numerous versions of evaporative pavements can also be utilized to reduce warming urban temperatures, including the use of porous pavers and permeable pavers. Porous pavers cool urban temperatures by increasing the surface area that interacts with ambient air (Lee et al., 2010). These pavers have internal holes filled with dirt, sand, gravel, or grass to hold moisture and allow water to drain through the surface into the base (Qin, 2015; U.S. Environmental Protection Agency, 2012). Pavers are often vegetated and can include reinforced turf or grass paving. While structurally porous pavers are available for any use, they are best applied in low traffic areas such as parking lots, alleys, and trails and may work best in climates that receive adequate moisture during summer months (U.S. Environmental Protection Agency, 2012). Permeable pavers are composed of a layer of concrete or fired-clay bricks. These pavers differ from other forms of evaporative payments as they allow rainwater to pass around the paver,

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rather than through it. The pavers are separated by spacing mechanisms that provide evaporation channels for water to travel from the surface layer to deeper layers (Qin, 2015). Considering the implementation of these forms of evaporative pavements are still relatively new, further research must be conducted on the sustainability and effectiveness of these materials as it relates to reducing to UHI in urban areas. Harnessing solar absorption from pavements also reduces surface temperatures. Heat harnessing pavement, through the form of solar energy harvesting, offers a way to collect solar energy by utilizing existing infrastructure (Lee et al., 2010). The most practical method to obtain such energy involves embedding highly conducive water pipes under asphalt pavements and recycling the heated water to warm buildings or produce electricity. Pavement heat can also be captured by solar cells and thermoelectric generators for use on small-scale applications like road advertising or street lighting (Qin, 2015). However, the use of heat harnessing pavement to mitigate UHI requires further research and verification. Given the sensitivity of the engineering, these forms of pavements cannot be subject to high traffic and heavy vehicle impacts and is extremely prone to corrosions if left sitting idle (Qin, 2015). These costs, along with those for reflective and evaporative pavements, are a critical consideration when assessing the effectiveness of cool pavement mitigation strategies. Cool pavement costs are influenced by a host of factors, including the city’s’ geographic location, local climate, time of year, underlying soil type and quality, expected traffic volume and desired life of the pavement (U.S. Environmental Protection Agency, 2012). Given the variability of these influences, costs are often project specific and limited information exists on general expenses. However, it is noted that porous asphalt is approximately 10-15% more expensive than traditional asphalt and porous concrete is 25% more expensive than its conventional counterpart (U.S. Environmental Protection Agency, 2012). Surface pavements are not designed to last forever and even the best constructed cool pavements are prone to wear and tear from consistent traffic and weather exposure. Outside of initial costs, which are traditionally higher than more conventional methods, life-cycle costs and environmental impacts must be considered as well. Despite cool pavements initial upfront costs, these expenses are often offset by reduced long term maintenance and upkeep costs (U.S. Environmental Protection Agency, 2012). For example, the use of permeable pavers can reduce long term municipal infrastructure expenses by reducing the need for other drainage features, such as inlets and storm water pipes.

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While construction expenses can be hefty, lower long-term costs are one of several benefits cool pavements can provide local communities. Installing cool pavements as part of an overall strategy to mitigate UHI within cities provides several benefits, including reduced energy use, improved air quality, reduced greenhouse gas emissions, increased pavement life and waste reduction, better water quality and stormwater management, and improved quality of life (U.S. Environmental Protection Agency, 2012). The use of cooling pavements reduces surface temperatures within cities, thus minimizing resident’s dependence on energy heavy appliances such as air conditioning units. Decreased energy demand not only lowers household costs but also results in lower associated air pollution and greenhouse gas emissions. Research supports findings that increasing pavement albedo to an average of 35% of 39% reflectance can achieve reductions in carbon dioxide emissions worth $400 billion (Pomerantz et al., 2000). Pavements with lower surface temperatures also keep groundwater runoff cool, minimizing shock to aquatic ecosystems in waterways into which the groundwater drains. The use of permeable pavements also allows water to sink into the pavement and the soil; this reduces storm water runoff and improves water quality as the pavers act as a natural filter against dust, dirt, and pollutants (U.S. Environmental Protection Agency, 2012; James, 2002). Reduction of pavement temperatures also slows the rate of ‘aging’ in pavement and reduces the probability of premature cracking and rutting (U.S. Environmental Protection Agency, 2012). Finally, cool pavements can provide city residents with improved quality of life standards including enhanced visibility at night, improved comfort due to lower ambient temperatures, and enhanced roadway safety due to improved water drainage and increased traction (U.S. Environmental Protection Agency, 2012). While numerous considerations must be taken into account when choosing to implement this mitigation strategy, the host of benefits it provides presents it as a viable option for municipal decision makers. 6.2.8 Heat island reduction policies

Often implemented in conjunction with urban design approaches, local and state governments have included UHI mitigation strategies in policies and regulations as well. Such actions have acted to remove barriers or provide incentives to implement UHI reduction strategies or prescribed minimum requirements in an attempt to avoid warming temperatures from the outset. Policy efforts include measures such as procurement, resolutions, tree and

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landscape ordinances, zoning and building codes, and green building standards (U.S. Environmental Protection Agency, 2008; Corburn, 2009; World Bank, 2010). Procurement actions on the part of local governments often involve purchasing cool technologies for municipal buildings; given that many municipal governments often put construction work and materials supplies out for bid, inclusion of UHI considerations can be incorporated through revision to bid specifications to include cooling materials and products (U.S. Environmental Protection Agency, 2008). Cities often modify procurement bids to include provision of cool roofing material and cool or porous pavement (Daley, & Byrne, 2016). Another approach includes the drafting and adoption of a UHI resolution, a document that states a groups awareness of and interest in an effort. Most often adopted at the local level by city councils, a resolution does not necessarily pledge financial support but can serve as a vital first step in kickstarting a host of UHI mitigation strategies including cool roofs, tree shading, and tree- saving ordinances (City of Austin - Urban Heat Island Initatives, 2015). Enactment of several varieties of tree and landscape ordinances can assist in ensuring public safety, protection of trees, and provision of shade. Three types of ordinances, in particular, are most beneficial in potentially curbing UHI effects: tree protection, street trees, and parking lot shade (U.S. Environmental Protection Agency, 2008; World Bank, 2010). Tree protection ordinances prohibit the removal or trimming of trees without a specified permit. While ordinances vary by municipality, many revolve around the protection of native trees or trees with historical significance (U.S. Environmental Protection Agency, 2008). Street tree ordinances mandate how to plant and remove trees along public right-of-way and publicly accessible land. These ordinances often designate the number and type of trees that should be planted as well as tree installation and maintenance (Street Trees). Finally, parking lot shade ordinances require parking lots to be shaded in order to cool pavement and cars, thus improving human comfort and reducing the effect of UHI and evaporative emissions from parked cars (U.S. Environmental Protection Agency, 2008). Zoning codes implement the goals and objectives of a comprehensive plan and dictate the function of an area, building height and size, population density, and parking requirements (U.S. Environmental Protection Agency, 2008). Codes can be used to enforce UHI mitigation strategies in a variety of ways; several U.S cities have crafted zoning codes for parking lot shading requirements and green roof bonuses, to name a few (City of Portland & of Bureau of

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Planning, 2018). Building codes operate in a more regulatory fashion, instituting standards for construction, modification, and repairs of buildings and other structures. Energy codes often fall within the broader text of building codes and can be a tool for reducing urban temperatures by mandating energy conservation requirements through the use of cool roofing (U.S. Environmental Protection Agency, 2008). Energy codes can include minimum requirements for solar reflectance and thermal emittance from cool roofs and the provision of building credits for those who chose to install cool roofing (Duke Energy; City of Chicago: Energy Conservation Requirements). Finally, green building initiatives that place a high priority on human and environmental health and resource conservation can also capture heat island reductions strategies. While green building standards vary across nations, many U.S cities have subscribed to Leadership in Environmental Design (LEED) and Green Globe standards (U.S. Environmental Protection Agency, 2008). While many of the aforementioned strategies can be utilized at various levels of governance, much of the burden of implementation is increasingly falling to local governments. Despite growing global concern over rising temperatures and climatic shifts, widespread decentralization of policy responsibilities has tasked many municipal governments with drafting and implementing UHI mitigation policies (Corburn, 2009). Policy is only as strong as the city governments that mandate it, so increasing attention must be payed to the presence of UHI and its consequences if effective local regulation is to be the result. 6.2.9 Modification of urban form

In an effort to promote passive forms of cooling within cities, modification of urban form can serve as a useful mitigation tool to promote natural ventilation within cities (Ng, 2009; Emmanuel, 2011). Tall buildings and dense settlements create urban canyons that trap warm air and harmful pollutants at ground level, raising urban temperatures and decreasing human thermal comfort. In an effort to minimize the urban canyon effect, thoughtful urban design based on the climate and existing morphology of the city can provide latent cooling effects. To be most effective, a city-wide strategy should be implemented with the general understanding that the more air ventilation that reaches the streets, the better it will be for dense urban areas (Ng, 2009). Effective, passive ventilation can be achieved through a number of design strategies including the development of breezeways or airpaths, varying building heights, and improving building permeability (Ng, 2009; Emmanuel, 2011).

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Plans to create new air paths or improve existing ones are often linked to improving city- wide permeability in an effort to channel wind along major roadways and penetrate breezeways deeper into city districts (Ng, 2009). The creation of new breezeways and promotion of existing ones is achieved through several design measures. These include proper linking of existing open spaces, creation of open plazas at street intersections, maintenance of low-rise buildings along prevailing wind paths and widening of minor roads connected to major streets (Plate, 1982). For cities on bodies of water, similar measures are crucial in harnessing the cooling power of local sea breezes. Building layout and height also shape city’s wind patterns and subsequent cooling abilities. In lieu of construction of structures with similar heights, variation in building height with decreasing heights towards the direction of prevailing winds provides more effective cooling channels for city structures (Ng, 2009). This design strategy is especially effective in high-density, compact cities who lack the ability to maintain proper distances between buildings. Finally, passive cooling can be achieved through improvement in building permeability (Plate, 1982). Creating viable space between buildings for wind channels to travel through not only removes heat and pollutants at the ground level but improves pedestrian comfort as well. Additionally, cooler temperatures for residents on lower floors equates to less energy use and subsequently less anthropogenic heat emitted from urban structures. Overall, the modification of urban form to minimize UHI and promote natural ventilation is a viable strategy. However, developmental pressures and high population densities can limit a city’s ability to implement such design measures effectively.

6.3 Mitigation strategies particularly valuable for cities in developing countries

6.3.1 Introduction While several UHI mitigation strategies were explored in depth in the previous section, the academic literature is sparse for identification of best UHI strategies for developing countries. Similar to the challenges faced when determining specific impacts of UHI on cities in developing countries, there is a lack of analysis or broader review of most beneficial practices specifically for developing countries. However, there are a number of published case studies of UHI vulnerability and mitigation strategies in specific developing country cities (Aflaki et al., 2017; Elsayed, 2012; Emmanuel & Johansson, 2006; Feyisa et al., 2014; Sodoudi et al., 2014; Thundiyil, 2003). These case studies are listed in Table 4, along with major UHI mitigation

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strategies identified as most feasible or optimal for those cities. Since the academic literature lacks more generalized recommendations for cities in developing countries, this section identifies mitigation strategies that are generally feasible for cities in developing countries based on the case studies analyzed in an attempt to provide an assessment of the most effective approaches that could be particularly valuable for cities in developing areas. In doing so, it is assumed that several general conditions apply to most cities in developing countries. Most exist in tropical or sub-tropical climates and have rapidly expanding urban populations, with some classified as ‘mega-cities’ (Emmanuel, 2011). Due to urbanization, these cities are quickly becoming denser and developed; many have lost critical green space that helps keep cities cool. As a result, four specific mitigation strategies were identified as most feasible and beneficial for cities in developing countries, which are discussed below. These are: increasing green space and urban vegetation; the implementation of green roofs; the use of high albedo or cool building materials; and modification of urban morphology and form. However, it is important to note that the effectiveness of these strategies is largely dependent on the environmental conditions of the city itself, including its climatology, geography, and surface topology. 6.3.2 Increased green space and vegetation

As urban populations continue to expand rapidly in cities in developing areas, green space is being compromised for the sake of development. However, loss of green areas is directly attributable to increasing temperatures in urban areas; spaces with less vegetation are more exposed to direct solar radiation and lack the evapotranspirative ability to cool their surroundings (Elsayed, 2012). Increasing green space, in the form of urban parks and outdoor spaces, in conjunction with enhanced vegetation cover can reduce the impact of UHI across cities in developing countries, regardless of size or climate. In Kuala Lumpur, capital city of Malaysia, the preexisting tropical climate coupled with rapid development has left the area vulnerable to the impacts of UHI, including excessive heat, increases in human discomfort and loss of work productivity (Elsayed, 2012). Haze related to rising urban temperatures is now a regular feature of the city skyline; similar trends can be seen in other developing South East Asian cities as well. In an effort to reduce such harmful impacts, increasing green space and plant cover has been proposed as an effective solution in minimizing UHI. Implementing tree planting programs

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within the city center (where UHI is highest) through the use of economic incentives or subsidies reduces core temperatures and increase shading, thus improving residents’ comfort and wellbeing. Steps toward this solution have already been taken as Kuala Lumpur pledged to increase greenery by planting 100,000 large-coverage trees by 2020 (Aflaki et al., 2017). Many of the city’s open areas are also covered with marble, granite, or tile that absorb large amounts of heat and release it back into the city, further exacerbating rising temperatures. Conversion of open space into green areas and small parks can improve the evapotranspirative capacity of the city and thus cool the municipality more effectively. Similar benefits have likewise been noted in other cities in developing countries; incorporation of 12% more green spaces in the bustling metropolis of Mexico City, Mexico can reduce overall temperatures by 1 ºC (Thundiyil, 2003). In conjunction with the cooling benefits vegetation can provide, the variation in design and composition of urban green spaces affords cities in developing areas the flexibility to adapt the strategy to best fit their circumstances. While park specific characteristics will shape its cooling efficiency, cities can modify the composition, canopy intensity, size, and shape of the space to exist within the context of their urban structures (Feyisa et al., 2014). Since many cities in developing countries operate in warmer, tropical climates, inclusion of greater vegetation density within green spaces is beneficial in enhancing the cooling effect on daytime air temperatures (Feyisa et al., 2014). Consideration of the size and quantity of green spaces is also important for cities in developing areas; since many face developmental pressures, it may not be feasible to allocate a large tract of undeveloped land for an urban park when many residents are living in precarious informal settlements. Development or conversion of smaller spaces, such as the open areas in Kuala Lumpur, can often be more effective at cooling urban climates at the micro-scale (city block) (Park et al., 2017). Greater volume of green spaces, though physically smaller, can also improve green space access and associated socio-economic benefits for residents who would otherwise be unable to reach them. However, if possible, preservation and/or construction of large urban parks is also critical for cities in developing areas. Large parks with climate specific vegetation provide a larger overall cooling effect on the city and can serve as economic hubs for both local residents and tourists who see such spaces as weekend destinations (Govindarajulu, 2014; Park et al., 2017).

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6.3.3 Green roofs

As explored in the previous section, the incorporation of green roofs as a mitigation strategy can provide cities a host of environmental and economic benefits. Green spaces absorb heat, provide shade, and filter air movement while reducing building heat gain (Shahmohamadi et al., 2010). Implementation of green roofs promote reductions in energy consumption, reduce resulting air pollution and greenhouse gas emissions, provide energy savings and most importantly, mitigate UHI effects. The flexibility in scale and design of green roofs as well as the resulting social and health benefits make it a viable option for many rapidly growing cities. Though no longer considered cities in developing areas, UHI mitigation strategies in the form of green roof plans in Tokyo and Singapore can provide a good model for other rapidly urbanizing, dense cities, especially those located in tropic or sub-tropic climates. In Tokyo, the implementation of the Green Tokyo Plan in 2000 has sought to reduce the impacts of UHI through restoration and preservation of green spaces (Thundiyil, 2003). With the hope of making roof gardens as common as staircases, the plan mandates that new construction with a total area larger than 10,000 meters must include rooftop greenery (Thundiyil, 2003). The city supports such mandates by providing tax incentives and subsidies for rooftop gardens on public buildings. Facing tight constraints on its urban sprawl, Singapore quickly developed upward instead of outward due to developmental pressures on limited amounts of available land. Adopting a ‘garden city’ approach, the city has sought unique ways to incorporate more green space into its compact development (Aflaki et al., 2017). Green roofs and rooftop gardens have already been placed on carparks and atop public housing, providing lower income residencies with cooling capabilities and access to viable green space (Thundiyil, 2003). In the private sector, commercial buildings and private developments have also expanded their inclusion of green roofs and rooftop gardens. Temperature differences due to inclusion of green roofs in urban design have been tangible; air temperatures have been reduced by up to 4 ºC in some areas of the city (Thundiyil, 2003). While these cases cannot be feasibly recreated in its entirety in many cities in developing countries, several elements of these plans can be implemented in various contexts. Replacing traditional roofs with green roofs on commercial and manufacturing buildings can provide both active and passive cooling benefits to indoor spaces. Research into the cooling effects of green roofs in the developing city of Kuala Lumpur support such assertions; implementation of green roofs reduces indoor air temperatures by nearly 7 ºC on warm

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afternoons (Aflaki et al., 2017). Many commercial buildings in the city already have flat roofs, making the transition to green roofs slightly more feasible. Additionally, concrete architecture in many Middle Eastern cities also improves municipal structures ability to bear the load of intensive and extensive green roofs (Hansen, 2018). 6.3.4 Use of cool building materials

Given that lower wind speeds are more prevalent in tropical cities, the cooling effect of building materials and their colors assume greater significance (Emmanuel, 2011). While aforementioned strategies, such as urban greening, play a crucial role in improving urban air temperatures they are less impactful in regard to enhancing residents’ thermal comfort. A more promising approach for cities in developing areas is investment in high-albedo, cool building materials (Emmanuel, 2011). Useful in spaces that cannot be effectively shaded by conventional means, cool materials both reduce surface air temperatures and energy use while increasing human thermal comfort. As cities in developing areas continue to urbanize and built areas continue to expand, inclusion of cool elements in building and pavement materials can minimize UHI formation from the outset. Roads and highways continue to comprise larger portions of urban spaces; replacing asphalt with white or light-colored pavement can significantly reduce surface air temperatures due to lower heat convection intensity (Shahmohamadi et al., 2010). Research conducted on the cooling effects of high albedo materials in megacity Tehran, Iran, support these observations (Sodoudi et al., 2014). As compared to current temperatures, inclusion of cool materials on buildings reduced temperatures between 0.2 and 0.8K due to greater reflection of solar radiation. Temperature reductions were even higher on roads with bright asphalt, with maximum and minimum temperatures lowered by 0.7 and 1.42K, respectively (Sodoudi et al., 2014). As cities grow upward, materials used on taller structures (such as skyscrapers) must also be considered; light color paint and high-albedo tiles are useful in cooling the building given that the sides are subject to long hours of sunlight exposure (Aflaki et al., 2017). With cost considerations an important factor in assessing best mitigation strategies for cities in developing countries, use of cool materials provides a cheaper and more flexible option for municipalities. While the use of cool materials in roofs and pavements often present greater upfront costs, reductions in long-term maintenance and upkeep fees offsets much of the initial financial burden (EPA, 2012). Conversion of preexisting pavements and roofs does not have to

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happen all at once; cities such as Mexico City base their needs assessment on analysis of existing road networks and associated repairs. For example, in the city there are currently 2,601, 758 meters of primary road that require corrective maintenance (Thundiyil, 2003). If the roads in need of corrective maintenance were repaved with light or white cement, it could improve the roads albedo from 0.1 to 0.35 and lower the pavements ability to absorb and retain heat (Thundiyil, 2003). Scaled up to include primary roads in good condition, more than 2% of Mexico City’s pavement could be converted to cooler options. While such improvements may appear small, they can produce a significant impact on temperature. Research has shown that small increases in surfaces albedo can reduce city temperatures by 1.5 ºC (Thundiyil, 2003). Often working most effectively in combination with another mitigation strategy, such as higher vegetation density, cool materials can create an even more noticeable cooling impact. In Kuala Lumpur, cool materials integrated with higher levels of vegetation were able to lower the city’s temperature by 2.7 ºC as compared to current environmental conditions (Aflaki et al., 2017). 6.3.5 Urban morphology and form

While several of the other mitigation strategies explored assume more active roles in cooling urban temperatures, one of the simplest and most effective techniques to reduce UHI in cities in developing countries is the modification of the urban form to promote natural ventilation (Shahmohamadi et al., 2010). A key strategy for improving thermal comfort and pollution dispersal since ancient times, it provides passive cooling around the clock. Given that UHI in cities is often most noticeable at night, modified urban morphology is beneficial in providing continuous ventilation to cool urban structures releasing their latent heat (Shahmohamadi et al., 2010). In tropical cities in developing areas, where wind levels are typically low it becomes even more imperative to consider ventilation strategies in the context of urban form to induce sufficient air movement (Emmanuel, 2011). Natural ventilation can be promoted in cities in developing areas in several ways. To ensure that winds are able to penetrate deeper into cities, development and maintenance of low-rise structures, widening of roads, and creation of open plazas at intersections must be adopted (Ng, 2009). If cities in developing countries are unable to accommodate such recommendations due to high densities or preexisting narrow streets, the adoption of step up configurations in building heights can promote good airflow if the difference in building heights are significant (Ng, 2009; Shahmohamadi et al., 2010). Arranging the opening of buildings to face prevailing winds can also move air more efficiently into households

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thus reducing energy use and improving local air quality (Shahmohamadi et al., 2010). Overall, cities in developing countries should begin to incorporate the notion of ‘more the better’ in designing and developing urban structures that encourage incoming winds and minimize thermal discomfort at pedestrian levels. However, such arrangements are often at odds with shading techniques employed in cities; the best street-level comfort conditions (especially in warmer climates) is associated with narrow streets and tall buildings while the worst is linked to wide streets with low-lying buildings (Emmanuel, 2011). Yet, tall buildings and narrow streets block the natural flow of air in cities, creating an ‘urban canyon’ effect that traps heat and pollutants at the surface level. Incorporation of these urban design suggestions may also be challenging for rapidly expanding cities as developmental pressures drive residents to quickly construct poorly ventilated, dense informal settlements. Nevertheless, incorporation of natural ventilation measures in cities in developing areas is not implausible. Kuala Lumpur, one of the fastest growing cities in Malaysia, has utilized step up configurations to reduce UHI within the city; staggering building heights promoted more even distribution of wind and allowed it to reach further into the city (Aflaki et al., 2017). In Colombo, Sri Lanka, urban form is largely characterized by low building density and many low-rise buildings (Emmanuel & Johansson, 2006). Given that the growing city lies on the coast, the presence of these buildings as well as narrow streets along the waterfront prohibit the sea breeze from penetrating further into the city. In an effort to mitigate such effects, the city has begun to open up the coastal strip to facilitate such natural ventilation efforts (Emmanuel & Johansson, 2006). 6.4 Specific challenges associated with implementing UHI mitigation strategies in cities in developing countries

6.4.1 Introduction

Though several mitigation strategies are feasible for cities in developing countries, preexisting structural and societal barriers make them challenging to implement effectively. Several of these limitations are explored below including poor governance and capacity within municipal entities, inability to finance mitigation strategies, and lack of awareness and communication both within local governance bodies and between municipalities and residents.

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Social and scientific limitations such as differing attitudes and values and absence of valuable research are also assessed.

6.4.2 Poor governance, capacity, and coordination

Organization and implementation of heat island mitigation strategies is not an easy task; such changes require complex coordination and alignment of goals and incentives among various stakeholders (Miner et al., 2017). Many cities in the developing world lack sufficient capacity, financial control, or political influence to efficiently and effectively deliver core functions and services. Unlike governance structures in developed cities, many municipal entities are disjointed and lack clear roles and responsibilities. In some cities, these ‘institutional voids’ prohibit tangible action from occurring due a scarcity of formal and informal rules and a lack of mechanisms and instruments for adaption (Weyrich, 2016). Lack of formalized environmental policy enforces such voids. In many developing regions, action to mitigate UHI has yet to be codified into law at the national level thus leaving it to cities to include UHI adaption in their activities. Conversely, some cities may struggle to implement tangible strategies due to ‘institutional crowdedness’, in which the presence of several institutional actors and unclear roles can create confusion about tasks and responsibilities and lead to the mismanagement of essential resources and funding for mitigation projects (Weyrich, 2016). Fragmentation, whether due to a lack of actors or too many, is a pertinent issue in the enforcement of climate policy due to the complex nature of the problem and coordination of action that is required at all levels of governance. An additional challenge to successful implementation of UHI mitigation strategies is the presence of conflicting time scales and conflicts of interest within and between municipal entities. The long-term nature of rising urban temperatures and success of mitigation strategies is often fundamentally at odds with the short-term outcomes pursued by local decision-makers (Weyrich, 2016). In order to implement many of the strategies previously explored, commitment to UHI mitigation cannot halt after initial implementation measures. Sustained funding and maintenance are required to see substantial results. However, upholding long term funding and support can be challenging when more pressing short-term issues, such as housing, take precedent. Rapid population growth and economic expansion, as well as immediate commercial and fiscal interests often conflict with enduring UHI mitigation strategies (Brown et al., 2012).

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Short-range results stemming from direct agendas are often more visible than long ranging adaption benefits, cultivating a cyclical response to satisfy immediate political and developmental goals (Weyrich, 2016). As exemplified in several of India’s mega-cities, the short-term economic benefits of converting land for development versus retaining it as open green space has led to short-sighted urban planning that has served to only worsen urban heat islands (Govindarajulu, 2014). Lack of capacity within municipal entities also hinders the effective execution of UHI mitigation strategies. A robust understanding of UHI as well as tangible skills to identify areas of improvement, backed by the ability to implement them effectively is a critical measure of institutional capacity, and one many cities in developing areas falter in (Brown et al., 2012). Cities that lack trained and knowledgeable staff often push UHI concerns to the back burner, prioritizing their focus on more manageable projects. Even though public decision makers are meant to lessen many of the barriers for the adaption of mitigation strategies, poor coordination, low political economy of long-term adaption measures, and conflicts of interest prohibit the effective implementation of proper UHI mitigation strategies (Weyrich, 2016; Govindarajulu, 2014; Brown et al., 2012). 6.4.3 Inability to finance mitigation strategies

Lack of available resources and financing mechanisms are two of the most influential obstacles in the development of sustainable UHI mitigation strategies in cities in developing countries. Many, if not all, of the mitigation strategies explored in previous sections require substantial initial investment; often, these high-up front capital costs act as a significant disincentive to invest in UHI mitigation practices (World Development Report 2010). Cities with low per capita income may find several of the strategies, such as restoration or construction of urban green spaces, too expensive or time consuming to pursue (Miner et al., 2017). For example, in Tehran, Iran, the high costs of implementing green roof technologies as compared to common roofs has deterred serious investment in the mitigation technique. Since the price of traditional roofing material is much cheaper, municipal planners and city residents are less likely to deviate from common practices (Lotfi, 2012). Even though numerous UHI mitigation strategies guarantee lowered expenses in the long-run, steep costs at the outset conceal many of the mid-term and long-term benefits. Insufficient financial capabilities can also influence a city’s capacity, both in employment and technology. Lack of access to financial capital can lead to a lack of critical staff, lowered capacity among existing staff, or shortage of staff expertise

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(Weyrich, 2016). The creation and implementation of cooling technology, often used in construction materials, is closely linked to the availability of financial resources. Conflicts of interest also play a crucial role in limiting the financial capacity of cities in developing areas to respond to UHI. Often. more immediate concerns, such as housing and social programs, are allocated larger shares of already strapped budgets, leaving little left over to be put towards long- range UHI mitigation strategies. 6.4.4 Lack of awareness and communication

Lack of awareness and poor communication between and amongst municipal entities and city residents about UHI and its impacts plays a substantial role in a developing city’s inability to institute urban cooling strategies. Communication on the impacts of UHI, adaption measures, and their implication for urban municipalities and residents is critical in gaining sustained support for mitigation projects (Weyrich, 2016). High rates of structural inefficiency and lack of knowledge about UHI and climate change at large limits social and political awareness of the severity of the issue. Without communication, urban residents, stakeholders, and public decision- makers are unsure about their role and potential mitigation efforts made thus far. As exemplified in attempts to implement green roofs in Tehran, Iran, lack of proper information about the necessity and benefits stemming from the project to residents, public officials, and investors discouraged the continuation of the project long-term (Lotfi, 2012). Low problem awareness can also be linked to low priority for UHI adaption at the municipal and state levels. Efforts to implement UHI mitigation strategies in Kula Lumpur were rendered ineffective due to lack of awareness of UHI by municipal planners. Little consideration was given to the role climate plays in urban design and development; this is due in large part to lack of exposure to climate responsive design, insufficient guidelines and procedures, and poor use of design tools (Elsayed, 2012). Many of the planners were more concerned with the aesthetics and beautification of the city, rather than implementing climate-responsive designs. Similar sentiments were expressed in Tehran, whose master plan did not utilize construction codes for the development of green roofs or firm regulations on green materials (Lotfi, 2012). City planners are critical agents in incorporating UHI mitigation policies into cities; they should be aware of and embrace the challenges UHI poses and understand the importance good planning has on improving residential comfort and sustaining quality living environments (Elsayed, 2012).

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6.4.5 Differing attitudes, values, and motivations

Individual perspectives, social norms, and cultural factors also play a role in determining the viability of UHI mitigation measures in cities in developing areas. Though concern over climate change and its related impacts, such as UHI, has expanded significantly over the past several decades, individual concern does not always translate to understanding of UHI drivers, dynamics, and response needed (World Development Report 2010). Given the long-term nature of shifting climate dynamics and rising urban temperatures, many city residents may feel that concern over UHI is a distant priority, making it difficult to generate support for mitigation strategies today. Deeply held attitudes, pre-existing values, norms, and beliefs play a crucial role in how residents in cities in developing areas perceive heat-related risk, how they assess climate impacts, and what knowledge they take into consideration (Weyrich, 2016). Political background, level of education, and trust in local government also shape resident’s willingness to support mitigation projects. Low levels of education among urban residents coupled with a lack of trust in municipal entities in cities in developing countries presents a significant barrier to UHI adaption measures (Weyrich, 2016). 6.4.6 Absence of research and reliable data

Barriers to the successful implementation of UHI mitigation strategies also stems from an absence of research and reliable data, as well as a disconnect between decision makers and scientists (Weyrich, 2016; Brown et al., 2012). Though research and data transparency has improved in several cities in developing areas, many urban areas still do not conduct climate research effectively. A lack of rigorous, verifiable research plays an influential role in the place UHI concerns land on the political docket. Although warming urban temperatures may be felt, the issue is considered low priority without effective scientific backing (Chandler et al., 2002). Inclusion of expert knowledge in public policy is often challenging in cities in developing areas as scientists are often excluded from the decision-making process. Leaving municipal planning bodies to understand, translate, and manage UHI data can lead to the disuse of available knowledge and confusion over which knowledge is vital to the planning process (Weyrich, 2016). Exclusion of local knowledge and pedestrian experiences also limits cities in developing areas capabilities to effectively plan and implement useful mitigation strategies.

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7.0 Conclusion

With climate change continuing to permeate the academic literature and mainstream media, it is important to consider the negative impacts its resulting consequences, such as UHI, will impart on global cities, particularly cities in developing countries. Fueled by shifting weather patterns, land use changes, high rates of urbanization and pollution, and inconducive urban design UHI is emerging as a critical byproduct of human activity and varying climatic changes. UHI related impacts, such as compromised public health, increased energy consumption, and stifled economic productivity can hinder socio-economic growth and minimize quality of life for urban residents. Cities in developing countries are particularly vulnerable due to their disproportionate dependence on environmentally linked industries, disadvantageous geographic location, and rapid rates of urbanization. Weak governance and poor infrastructure also play a role in a city’s vulnerability; however, these concerns lack substantial academic backing and require further research to fully evaluate their impact on UHI. Broadly, research on the connection between UHI and particular vulnerabilities of cities in developing areas is sparse, leading to a noticeable gap in the academic literature. Lacking research on particular cities in developing areas relationship to UHI, several vulnerable developing areas are identified. These included West and Sub-Saharan Africa, South-East Asia, and South Asia. Numerous urban design strategies, including the expansion of vegetation and green spaces; implementation of cool materials, roofs, and pavements; green roofs; vertical greening; and modification of urban form coupled with dynamic heat island reduction policy are identified as the most effective means of achieving climate resiliency and reducing UHI. However, developing cities face unique challenges that can hinder the success of these approaches; poor governance and lack of capacity, poor awareness at the local and municipal level, an inability or unwillingness to finance these strategies, differing attitudes and values among residents, and an absence of research and data can all impact a city’s ability to effectively minimize its urban temperatures. Developing cities must address these limitations and modify mitigation practices and policies to best fit the context of their urban environment. UHI stands only to worsen as cities in developing countries continue to grow and economies expand. Such cities must recognize the consequences of inaction and begin to implement heat minimizing urban designs and heat island reduction policies to ensure cooling benefits for not only current residents but for those in generations to come.

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Tables

Table 1. Physical causes of Urban Heat Island Effect (UHI)

Physical Causes of Urban Heat Island Effect (UHI)

Cause Description Relevant Citations: Two primary weather conditions Cole et al., 2008; Mishra et al., Weather affect UHI: wind and cloud 2015; Mohajerani et al., 2017 cover. UHI appears to be strongest during periods of calm winds and clear skies. Lack of vegetation and reduced Cole et al., 2008; Taha, 1997; Reduced vegetation in urban ability for evapotranspiration Kokthar et al., 2019; Yuan & areas play an important role in Bauer, 2007 promoting UHI. Vegetation is replaced with dry, impervious surfaces that evaporate water less quickly and contribute to higher temperatures. Modification of land surfaces Kumar et al., 2017; Guo et al., Modification of land surfaces through urbanization is 2015; Kalnay & Cai, 2003; Oke, and land use change considered one of the most 1973; Mohajerani et al., 2017 influential drivers of UHI. Heat generated by cars, industry Cole et al., 2008; Taha, 1997; Anthropogenic heat and other man-made sources is EMPRI, 2017; Li & Zhao, 2012; more prevalent in cities with de Laat, 2008; Fan & Sailor, high population densities. 2005 High rates of pollution can Sanford, 2011; Li et al., 2018; High rates of environmental modify the radiative properties Cao et al., 2016; Ramanathan et pollution of the atmosphere. al., 2007; Climate and topography, as well Cole et al., 2008; Mohajerani et Background climate and as a cities geographic location al., 2017; Zhao et al., 2014 geographic location can influence UHI formation. Properties of urban materials, Cole et al., 2008; Mohajerani et Properties of urban materials including solar reflectance, urban al., 2017; Solecki et al., 2005 emissivity, and heat capacity play a critical role in determining how the sun’s rays are reflected. The urban dimensions of a city Cole et al., 2008; EMPRI, 2017; Urban geometry and design can influence wind flow, energy Rajagopalan, Lim, & Jamei, absorption, and a surface’s 2014 ability to emit heat back into the environment.

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Table 2. Negative impacts of the Urban Heat Island Effect (UHI)

Negative Impacts of the Urban Heat Island effect (UHI) Impact Description Relevant Citations Energy Consumption and Environmental Impacts Increased energy consumption Increased temperatures during Rinkesh, 2019; EPA, 2008; warmer months intensifies Arifwidodo & Chandrasiri, demand for energy use 2015; Liao et al. 2017; Li et al., 2019 Elevated greenhouse gas Increased use of energy Cole et al., 2008; EPA, 2008; emissions and pollution increases greenhouse gas Liao et al. 2017 emissions as many cooling systems rely on fossil fuels for energy generation Health Impacts Increase in preexisting and Urban heat often worsens pre- Cole et al., 2008; Peterson, chronic health conditions existing and chronic health 2017; O’Neill & Ebi, 2009; conditions, including asthma, heart and lung disease, kidney problems, and diabetes Impacts most vulnerable Extended periods of warmer Cole et al., 2008; Sarofim et al., members of society weather disproportionally 2016; Heaviside et al., 2017; impact the health of children, O’Neill & Ebi, 2009 the elderly, and those with preexisting conditions Increases in heat related Higher temperatures can induce Dang et al., 2018; O’Neill & illnesses and mortality heat related illnesses including Ebi, 2009; Baccini et al., 2008; heat cramps, heat exhaustion, Patz et al., 2005 heat strokes, and heat mortality Economic Consequences Heat-related economic losses Heat related economic losses Mike 2017; Dell et al., 2012; are projected to be 2.6x higher Singh et al., 2015; Daanen et in cities with UHI al., 2013

Decreased levels of output and Warmer temperatures prohibit Yu et al., 2019; Singh et al., work productivity agricultural and industrial 2015; Sudarshan &Tewari, output and limit worker 2014; Daanen et al., 2013 productivity due to heat stress in working environment Harm sensitive aquatic Warmer temperatures disrupt Cole et al., 2008; EPA, 2008; ecosystems and marine related aquatic ecosystems, which Somers et al., 2013 industries many local economies depend on for sustainment

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Table 3. UHI Mitigation Strategies

Mitigation Strategy Benefits Costs Citations . Cools surface and . Expenses include EPA, 2008; Block et al., 2012; ambient temperatures materials, initial Nuruzzaman, 2015; Ballinas & . Reduces energy planting, and Barradas, 2016; Tan et al., Increased planting of trees and consumption ongoing maintenance 2016; Armson et al., 201; vegetation . Reduce air pollution . Life cycle cost of a Akbari, 2005 and improve air tree is between $300- quality 500/ per tree . Provides shading . Cools urban micro- . Quantifying costs is Block et al., 2012; WHO, climates largely city-specific 2011; Wong & Yu, 2005; . Minimizes air . Costs based on size Feyisa et al., 2014; Park et al., pollution and shape of space as 2017; Dang et al., 2018; Lee et Urban green spaces (i.e. parks) . Provides space for well as species al., 2015 physical activity and planted social gatherings . Reduces heat-related stress and mortalities . Shades heat . Larger upfront costs Wong, 2005; EPA, 2008; absorbing materials . Installation costs Lehmann, 2014; Liu & . Provides vary depending on Baskaran, 2003; GSA, 2011; evapotranspirative design and materials Block et al., 2012; Gago et al., Green roofs cooling used 2013; Kohler et al., 2002; . Minimizes energy . Range from $10-$25/ Perini et al., 2011; Peck & demands sq. foot Callaghan, 1999 . Increases urban . Long term biodiversity maintenance costs must be considered . Provides thermal . Installation costs are Block et al., 2012; Pérez- insulation and high Urrestarazu et al., 2015; Price reduces internal . Requires long-term et al., 2015; Rahkshanderoo et temperatures of upkeep (pruning, al., 2015; Perini et al., 2011 Vertical greening: vegetated buildings replanting etc.) facades and walls . Reduce air and noise . Plant mortality rates pollution must be included in . Improve ground level long-term costs thermal comfort . High rates of water waste . Increases urban . Relatively low-cost Akbari et al., 2016; Synnefa et albedo as compared to al., 2008; Santamouris et al., . Maintains lower greener options 2008; Gartland, 2008 Building materials surface temperatures . Modification of . Provides cooling existing materials benefits across keeps costs lower seasons with greater . Costs vary depending efficiency on material . Reduces energy . Potential to create EPA, 2008; Akbari, 2005; consumption and harmful glare Blasnik, 2004; Konopacki et increased energy . Cost between $0.75- al., 1998 savings $1.00/ sq. foot Cool roofs . Reduces air pollution . Single ply membrane . Improves human more expensive but health and comfort does not require . Longer length of extensive useful life maintenance

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. Lowers surface . Costs are influenced EPA, 2012; Qin, 2015; Lee et temperatures due to by location, climate, al., 2010; Pomerantz et al., Cool pavements higher albedo and traffic volume, etc. 2000; Wong, 2005 reflectance . Cool materials are . Can collect solar more expensive than energy conventional . Facilitate evaporative alternatives cooling . Lower long-term . Increases pavement costs life . Removes barriers and . Policy is only as Corburn, 2009; World Bank, provides incentives effective as the 2010; EPA, 2008; Daley & Heat island reduction policies . Prescribe minimum municipal Byrne, 2016; City of Portland requirements to government that & of Bureau of Planning, 2018 reduce UHI mandates it . Flexible to city needs . Decentralization makes effective implementation challenging . Improve passive . Costs are very city Aflaki et al., 2017; Emmanuel, cooling specific 2011; Ng, 2009; Plate, 1982 Modification of urban form . Promote natural . Design strategies ventilation within may be less effective cities in compact, densely . Mitigate urban populated cities canyons

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Table 4. Review of feasible UHI mitigation strategies in developing cities

Case Study Citations Cities Analyzed Mitigation Strategies Identified Aflaki et al., 2017 Kuala Lumpur, Singapore, Hong . Green roofs Kong . Vertical greening . Modification of urban form . Cool construction materials Elsayed, 2012 Kuala Lumpur, Malaysia . Trees and vegetation . Modification of urban form Emmanuel & Johansson, 2006 Colombo, Sri Lanka . Trees and vegetation . Modification of urban form Feyisa et al., 2014 Addis Ababa, Ethiopia . Urban green spaces Sodoudi et al., 2014 Tehran, Iran . Green roofs . Cool construction materials . Urban green spaces Thundiyil, 2003 Mexico City, Mexico . Urban green spaces . Cool construction materials

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Appendix: Literature Reviews on Planning Strategies for Cities in Developing Countries to Climate Change Impacts

This research was completed through a rigorous review of secondary sources: literature and, in some cases, secondary data. The primary focus of the literature review was peer- reviewed academic studies. However, in addition, non-peer-reviewed but highly relevant and valuable reports and studies, including those completed by international development agencies such as The World Bank and the United Nations, as well as reports from national government agencies such as the US Environmental Protection Agency (US EPA), were reviewed. Literature review was conducted through rigorous searching of peer-reviewed and non-peer-reviewed sources using systematic keyword search phrases, which were then systematically modified based on trends from the literature. Literature sources, abstracts and PDFs of papers were systematically compiled using the Mendeley bibliographic software. In some cases, relevant secondary data compiled by reputable sources was also reviewed to identify key trends. The initial focus of this Honors Thesis research was not originally confined only to UHI effect planning strategies for cities in developing countries and developing areas, but more broadly to cities in developing areas planning strategies for climate change mitigation. A much broader literature review was completed on the following topics: 1. Planning strategies for cities in developing countries for sea-level rise mitigation. For this, two sub-topics were researched: a. Planning strategies for sea-level rise mitigation through governance or policies that do not involve actual infrastructural changes, such as tax incentives, etc. b. Planning strategies for sea-level rise mitigation through infrastructure or engineering approaches; 2. Planning strategies for cities in developing countries for increased flooding due to climate change; 3. Planning strategies for climate change’s impact on food security in developing countries 4. Planning strategies to reduce uncertainty and improve resiliency city planning (RCT) 5. Ecosystem services and climate change 6. Consideration of social-ecological systems in planning for climate change 7. Food-Energy-Water (FEW) framework and planning for climate change

Planning strategies for cities in developing countries for sea-level rise mitigation through governance or policies

The notion of incorporating both environmental and governmental factors into one comprehensive strategy has also been explored in a number of academic case studies. The

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concept of ecosystem-based adaption, which emphasizes adaptive management and governance processes aimed at promoting the sustainability of goods and services provided by coastal ecosystems while still protecting critical ecosystems is one such example. Carro et. al (2018) examines the notion of an ecosystem-based adaption strategy to cope with sea level rise on the Uruguayan coast. Implemented at Kiyu, or the Uruguayan coast of the Rio de la Plata river estuary, ecosystem-based adaption was synthesized into an integrated coastal management framework, which served to vocalize the concerns of local stakeholders in conjunction with national level decision makers while facilitating the implementation of ecosystem adaption measures to preserve existing coastal systems. Stakeholder’s participation in the process, coupled with strong ecological mitigation recommendations, allowed the program to achieve relative success while providing social legitimacy and trust in the process. Major improvements included the rapid recover of sandy beaches and dunes, improved local and national budgeting for ecosystem adaption measures, and mainstreaming of the ecosystem-based adaption approach at both the regional and national level. While such a framework may not work within the socio- political context of every developing nation, the incorporation of public concern with preexisting environmental factors may prove to be beneficial in areas where tourism is critical, or livelihoods are dependent on coastal activities. Uruguay is not the only nation to begin incorporating ecosystem-based adaption strategies. Bangladesh has also begun to implement similar measures, albeit in a more spontaneous manner, and have coupled it with a host of resilience projects including coastal infrastructure improvements. The nation’s success in such measures is explore by Filho, et al. (2018) along with the work of three other developing nations, Brazil, Cameroon, and Uruguay. The adaption strategies presented were synthesized into two broad categories: classical adaption strategies and innovative adaption strategies. While more traditional strategies have been implemented, such as Brazil’s inclusion of an institutional national level ICM more unconventional governance strategies have also emerged. This includes bottom-up scenario planning and community-based adaption strategies, as exemplified by the practices of the Bangladeshi government. While gaps in exposure and vulnerability remain within and between developing nations, the adaption of more innovative strategies proves promising in addressing and mitigating against sea level rise in the long term.

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Specific attention must also be paid to cities in developing island nations, who often receive the brunt of the media attention surrounding rising sea levels and the negative impacts of climate change. Often coined as “drowning islands” developing island nations, such as the Republic of Kiribati, are facing elimination of their coastal livelihoods, environmentally induced mass migration, and large-scale loss of land. Using Kirbaiti as an example of what not to do to address future climate concerns Mallin (2018) notes how the country’s use of top- down authoritative planning strategies fails to incorporate local island communities. In order to develop best practices to address the pressing threat of climate change, Mallin argues that communities must play a crucial role in planning and policy formulation. Such local involvement not only builds trust between residents and their government but can produce culturally sensitive and locally supported planning decisions and adaptive strategies.

Planning strategies for cities in developing countries for sea-level rise mitigation through engineering and infrastructure changes

The notion of adapting to sea level rise through climate sensitive architecture and physical structures has a growing presence in the academic literature. Several design principles have been introduced, including the concept of floating structures and floating communities. El- Shihy and Ezquiaga (2019) further explore these concepts within the context of addressing sea level rises’ impact on Abu-Quir, Egypt. Noting that the city is in one of the most vulnerable areas of the Nile Delta coastline, the authors propose floating communities as the most sustainable and long-term solution in lieu of more traditional land reclamation practices. A straight-forward design, floating communities are simply man-made island like platforms that act as floating land on water. They are often comprised of a large pontoon floating structure, mooring facilities, access bridges, and breakwater. Several benefits are derived from the implementation of floating structures including their relative cost-effectiveness, minimal ecological impact, and ease of construction (or dissemblance). While the authors support the concept of floating structures within the context of the Nile Delta, they also acknowledge that this design strategy lacks tangible examples of successful implementation and may not be

successful in all low-lying coastal areas impacted by sea level rise. Following a similar design trend, the concept of artificial islands can serve several critical purposes for developing nations including land preservation and reclamation, human habitats,

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and markers of state sovereignty. The development of artificial islands is already a popular concept for land preservation in the South and Southeast Asian seas, especially for larger construction works such as airports and harbors. Major artificial island projects have occurred in Hong Kong, Singapore, and the Maldives. Artificial islands are also increasingly being used for human habitation as well. In the case of the Maldives, the state created the artificial island of Hulhurmale to house the increasing population of the Maldives capital of Male. Built 2 meters above sea level, the island is designed to meet the future needs of the state in terms of housing, industrial, and commercial development. Finally, the literature also emphasizes the importance of artificial islands as “markers” of sovereignty for regions where the ocean would submerge parts or even cover completely low-lying nations. Vernacular architecture, or the concept of designing and constructing areas with the use of local materials and architectural design practices, is also emerging as a potential method in addressing sea level rise (and more broadly climate change). Utilizing the small nation of Cyprus as an example, Philokypro et al. (2017) examines the role environmentally responsive design plays in the coastal and lowland regions of Cyprus. Researchers found that design varies across regions, especially in regard to building typology, open space configuration, construction techniques, and materials. Drawing from the varying environmental factors that influenced the differing design techniques, the research results determined that vernacular architecture addressed successfully the specific adaption challenges imposed by local conditions.

Planning strategies for cities in developing countries for increased flooding due to climate change

Often a consequence of rising sea levels and increased rates of natural disasters, flooding in developing cities has become a pertinent issue, especially when examined through the lens of urban planning. From a policy and planning perspective, one proposed answer is the widespread development and adaption of strategic environmental assessments (SEAs) into mainstream planning practices in developing nations. Defined as a systematic process for evaluating the environmental consequences of proposed policies and plans, SEAs are useful in incorporating climate change adaption practices into the broader planning context. Examples of SEA have already been adapted in various forms in numerous cities across the developing world. Such examples include Semarang City, Indonesia in which the local government mandated SEAs be

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performed for spatial planning measures to mainstream rising climate change concerns with traditional planning practices as well as bolster the city’s disaster response capabilities. The island nation of Jamaica has also integrated SEA into its national policies, not only to improve its disaster response capacities (i.e flooding events) but to plan for key development sectors that are the most vulnerable to flooding and climate risks (i.e. fishing and agricultural sectors). While many challenges exist within this solution, the incorporation of climate change assessments into broader national planning strategies upfront can assist developing cities in proactively mitigating

against potential flooding catastrophes, instead of being forced to respond reactively. Using Ho Chi Minh City as a guide, Eckert et al. (2009) developed the notion of a “Green Agenda”, a three-level strategy that incorporates the environmental threats facing the city, international best practices, and existing ground knowledge to promote sustainable urban development within the city. Level 1 focuses on the regional and city level and the creation of strategic development guidelines, which divides the city into four typological categories: urbanization promotion (areas with a low risk of flooding and lack development) urbanization control area (areas with high risk of flooding and lack of development) high risk areas (high risk of flooding and high rates of development) and redevelopment areas (low risk of flooding and high rates of development). These criteria serve as a guide for future development, with an emphasis placed on urbanization promotion and redevelopment areas. Level 2 focuses on the neighborhood level, with development and design ideas outlined to mitigate against urban flooding and climate changes. Such improvements include green roofs, upland and lowland reservoirs, separate drainage systems, and designation of protected areas. Finally, Level 3 emphasizes the building level with a focus on guidelines for energy and climate efficient housing. While this adaption strategy is quite extensive, it’s multi-level approach would be beneficial to recreate in developing nations who struggle to address climate change planning in a holistic manner. Large volumes of informal settlements also exist within many developing cities, due in part to high rates of climate change induced urbanization. Those living in informal settlements are especially vulnerable to climate hazards due to structural poverty, high densities, and subpar physical infrastructure that define their living conditions. As exemplified in Kikwaski & Mbuya (2019), those that live in informal settlement utilize a variety of coping mechanisms to address the vulnerability of their homes to flooding events. These include building barrier walls,

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applying extra cement finishing, drilling holes in the wall to let water out, and raising toilet heights above normal flood levels. While these strategies may work in the short term, the poor quality of the materials and the location of the settlements prove to fail in the long term. In an effort to improve the resiliency of urban informal settlements in the short term, use of quality building materials and technicians, improvement of surface water drainage and training of

residents on the effects of climate change is recommended

Planning for climate change’s impact on food security in developing countries

Climate change poses a considerable threat to global food security, with a pronounced concern for agriculture dependent nations. Food production is critically dependent on a number of environmental factors, such as local temperatures and precipitation conditions, with any shift requiring farmers to adapt their practices and reallocate already scant resources. While small scale farmers are more likely to experience first-hand the challenge of adapting to climate change, the trials also extend to the national level (who is tasked with providing supporting policy and infrastructure environments) and the international level (who is responsible for maintaining global trading schemes). Such assertions are widely supported by the academic literature, as exemplified by Barnett (2011) research into the effect of climate change on food security in the Pacific Islands. Researchers found that increasing temperatures, variations in rainfall, and increases in sea-level all negatively impact the region’s ability to produce food and maintain its fisheries, one of the driving economic forces in the area. While the author acknowledges that the food security dilemma is not as pronounced in the Pacific Islands as in parts of South Asia and Africa (largely because poverty is not as acute), research still supports the notion that climate change has begun to negatively impact agricultural production for both subsistence and commercial purposes as well as damage the variability of supply for the local fisheries. While the islands were the area of focus in this academic piece, the larger trends observed in the research can be applied globally to other regions facing similar conditions as well. Utilizing an experimental Hunger and Climate Vulnerability Index, which shows the relative vulnerability of food insecure populations to climate risks at the national level, Krishnamurthy et al. (2014) finds a high correlation between hunger and climate risk, especially in regions that are already negatively impacted by food insecurity (such as sub-

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Saharan Africa and South Asia). While still in the theoretical phase, such an index could be a beneficial tool for planners in determining vulnerable areas, evaluating potential effectiveness of

programs, and promoting the notion of adaptive capacity planning. Analyzing case studies from around the globe, Leeuwis and Hall (2010) examine the role innovative support services for climate adaption play in preparing local farmers for changing environmental conditions. Focusing on Bangladesh, Bolivia, the Democratic Republic of Congo, and Ghana, researchers found that agricultural adaption projects were primarily focused on distributing new technologies to farmers (ex: new varieties of crops, water harvesting, rotating crop systems, etc.) and was largely coordinated at the local level. While this is beneficial to an extent, the lack of attention payed to changing higher level conditions and policies hindered the nations abilities to cultivate a more conducive environment for technological change and adaption. The lack of coordination and support beyond the local level has produced a vacuum regarding the provision of broader innovative support services at both the country and international level. While technical change for farm-level adaptation and mitigation is needed, a change of policy and institutional regimes that govern agricultural production, value chains and natural resource management is also vital to the success of food sensitive regions. Such adaption measures become acutely more important to smaller, subsistence-based farming households who are found to be 1.73 times more food insecure following climate shocks (such as droughts, floods, and heat waves). Research has found that increasing productive capacities of smaller farmers can help to safeguard food security in the event of future climate shocks especially when coupled with access to proper fertilizer, pesticides, veterinary medicines, and larger livestock.

Planning strategies to decrease uncertainty and improve resiliency city planning (RCT)

The notion of planning for uncertainty, especially in the face of rising environmental threats, has begun to grow both within the academic literature and in practice. Berke & Lyles (2013) examines how the increasing rate of uncertainty spurred by climate change is fundamentally at odds with the traditional predict-and-plan strategy of conventional planning methods. In lieu of more reactive approaches, the authors offer a coupling of collaborative and anticipatory governance models in order to best address public risks associated with climate change and cultivate more resilient cities. Under this hybrid governance model, collaborative

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governance would still embrace the traditional approach of open dialogue and consensus building while expanding further to include “communities of practice”, in which the group is not assembled just around a specific problem but a larger host of issues that the members know and care about. Anticipatory governance would be incorporated through a focus on planning for the acceleration and complexity of climate shocks as well as identifying unforeseeable events sooner. The incorporation of both modes of governance not only allows communities to anticipate and mitigate future challenges linked to climate change but helps to build a public constituency by engaging a variety of stakeholders. Transitioning to planning focused on consideration of multiple future scenarios, more flexible policies, and assessment-based implementation policies will afford cities the flexibility to prepare for and respond to climate change in a more proactive and productive manner in the future. Resiliency city planning (RCT), as introduced by Jabareen (2013), focuses on reducing the risks presented by climate change and improving the resiliency of cities to address these risks head on. Broadly defined as a network that provides a comprehensive understanding of city resilience, RCT is composed of four distinct concepts, each having its own roles and responsibilities within the larger framework. The first is the urban vulnerability matrix, which focuses on the governance culture of a resilient city as well as the spatial and socio-economic mapping of future risks. The urban governance concept emphasizes the holistic management of urban resilience through a focus on innovative urban policies, integrative governance, deliberate decision making, and ecological economics. The concept of prevention represents the components that must be considered when working to mitigate climate change impacts, such as the adaption of clean energy. Finally, uncertainty-oriented planning emphasizes that planning should adapt resilient methods to help cities not just cope, but actively prepare for uncertainties in the future. While RCT is still largely conceptual, the framework established serves as a

beneficial primer for cities to modify and adopt in coming decades.

How the World Bank is approaching climate change in developing countries

As one of the premiere leaders in international aid and development, the World Bank has taken a strong interest in the effect climate change and its consequences have on low- and middle- income countries. Numerous reports have been published in the past decade analyzing the role climate change externalities such as extreme heat, increased levels of participation, and flooding

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has played in compromising developing nation’s economic growth, poverty rates, and food production capabilities. One such report, Gupta (2014), reviews the relationships between population, poverty, and climate change. Emphasizing a common sentiment found in the academic literature, the report notes that while developing countries contributed little to the current status of the climate, they will disproportionally share the burden of its consequences. However, the report deviates from recommending more mainstream solutions, such as carbon taxes, in favor of policies that cap population growth in developing countries. Policy intervention is especially encouraged for countries with high fertility rates that still have very low per capita emission levels. Several benefits can be derived from more stringent fertility policy including more available resources to invest in future economic growth, disaster management, and disease control and prevention. It will also reduce demand for jobs as well as generate greater female workforce participation. Most importantly, it will benefit poorer countries by reducing the pace of global warming and its associated consequences. Family planning programs are relatively simple, effective, and inexpensive ways to achieve a host of benefits for poorer

countries and one of the simplest and effective means to improve their circumstances. Mendelsohn & Dinar (1999) report also paints a more optimistic picture for developing countries. Examining the impact of climate change on agricultural production in low-income countries, the report stresses that current agronomic studies are too pessimistic in their assessment of future food security crises. While the report does not discount that climate shocks will lead to large agricultural losses in developing countries, it also takes into account several reasons that future climate projections may not appear as bad as they seem. One, the exclusive focus on grain in agroeconomic studies, which tends to prefer more temperate climates, excludes tropical and subtropical crops. Second, these studies tend to underestimate the importance of efficient adaption measures at the household and municipal level as a mechanism to reduce damages. Farmers tend to self-adjust to their local climates and public policy that reduces their vulnerability through mandatory adjustments of cropping patterns and methods as well as improved communication of weather monitoring and climate forecasts. Provision of improved technologies, such as heat-tolerant crops, can also assist in mitigating climate changes effect on

agricultural production. Using future forecasting models, the Potsdam Institute for Climate Impact Research and Analytics (2013) produced a report for the World Bank examining the impacts of present

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day, 2°C and 4°C warming on agricultural production, water resources, and coastal vulnerability in in Sub-Saharan Africa, South East Asia and South Asia. Several key issues are highlighted in the report including the early onset of climate impacts, uneven regional distribution of climate impacts, and interaction among impacts that can lead to cascading consequences. Heat extremes are expected to occur far more frequently and cover larger areas of land, with extreme temperature increases anticipated in South Asia in the near term. Declines of 20 percent in water availability are projected for many regions under a 2°C warming and of 50 percent for some regions under 4°C warming. For the regions studied, increases in temperatures were also associate with risks for reducing crop yields and production losses with strong repercussions for food security within the regions. As temperatures continue to rise, each of the regions will also face increased risks of breaching critical thresholds. When natural and human systems are pushed beyond critical thresholds, abrupt system changes can result leading to negative impacts on the goods and services they provide. Each region was found to have differing tipping points; sub-Saharan Africa’s food production capacities are increasingly at risk while South East Asian nations rural livelihoods continue to be threatened by sea-level rise. Increased precipitation due to disturbances in the monsoon system also threaten large portions of South Asian populations.

Ecosystems services and climate change

Ecosystem services are defined as “the many and varied benefits that humans freely gain from the natural environment and from properly-functioning ecosystems” (Ecosystem Services, 2019). Environments such as agrosystems, forest ecosystems, grassland ecosystems, and aquatic ecosystems can provide a plethora of resources, such as agricultural produce, timber, and aquatic organisms, when functioning in a sustainable manner. Quantifying the impact of climate change and rapid urbanization through the lens of ecosystem services has grown in popularity in the academic literature, as exemplified by the work of Camacho-Valdez et al. (2019). Focusing specifically on the urban wetlands’ ecosystem in Chiapas, Mexico, researchers examined and quantified the critical role wetlands ecosystems play in providing crucial services to the local community and the threat rapid urbanization poses to such systems. Urban wetland ecosystems (consist of wetlands, parks, gardens and yards), when functioning properly, can provide a host of services to urban dwellers including water purification and filtration, flood control, groundwater retention, and provision of natural habitats. However, rapidly expanding

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populations threaten critical ecosystems in a number of ways, including promoting loss of biodiversity, noise, water and air pollution, higher GHG emissions, and increased stormwater runoff. Using GIS and remote sensing satellite technology, researchers were able to spatially map and identify land use/ land cover changes in relation to ecosystem service provisions and identify areas where growth needed to be redirected away from sensitive ecological areas. Such mapping strategies were found to also be useful to land managers and policy makers who are interested in understanding the relationships among urban ecosystems and the services they provide urban residents. Moving towards a different province in the developing world, Mugari et al. (2019) assess the fluctuations in the delivery of critical ecosystem services in the semi-arid district of Bobirwa, Botswana, and the adverse effects such fluxes can have on local people’s livelihoods and wellbeing. Given the environmental characteristics of the region, limited livelihood options prohibit many of the regions residents from diversifying their incomes, leaving them to rely on an already declining supply of ecosystem resources. Researchers identified several key ecosystem services in the Botswanan sub-district, noted key changes in the availability of such ecosystem services from 2006-2016, and analyzed the impacts the changes brought to the local community. They found the primary ecosystem services of the region to be woodland areas, pasture/ grazing land, and aquatic ecosystems. Although the farmlands provide the least number of ecosystem services, this was reported to be the most important land-use type over the years, as it provides food for subsistence purposes for most of the households. Climate and growth driven change have compromised most every single ecosystem service in the past decade, with the most notable impacts felt in the provision of local agricultural goods, firewood, and natural pastures. In an effort to mitigate against such changes and the diminishing quality of life in the region, researchers emphasized the need to incorporate more indigenous knowledge of local environments through participatory mapping processes that allow local communities to collaborate with municipal governments to best identify important ecosystem services as well as the land use providing them. Such processes provide critical baseline information in data-poor regions which can facilitate informed, relevant and timeous decision-making regarding the management of local ecosystem services which can improve the adaptive capacity of both social and ecological systems.

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Examining the link between ecosystem services and food security in one of the poorest nations in the world, Malawi, Poppy et al. (2014) proposes a new ecosystem framework coupled with a policy response framework that allows food security to be delivered alongside healthy ecosystems. The ecosystem framework contains three critical components: multiple scales of analysis, disaggregation of beneficiaries, and tradeoffs for decision makers. These elements, when linked with more dynamic policy making initiatives, can assist in ensuring and promoting food security within even the poorest nations. Unfortunately, challenges remain in implementing this within the developing world as status quo policies and attitudes hinder the expansion of knowledge on identifying and protecting vulnerable populations and ecosystem services.

Consideration of social-ecological systems in planning for climate change

Social- ecological systems, which consist of bio-geo-physical units and their associated social actors and institutions, have grown in popularity within the climate change related academic literature. While most current knowledge revolves around the fact that climate change and its associated consequences are indeed real and worsening and the notion that cities must become more resilient to such challenges, less attention has been paid to assessing climate change within a social context. With most academic articles operating under the assumption that all facets of society are willing to participate in climate driven adaptive measures, Adger et al. (2009) take a different approach through their analysis of the social limitations of climate change policy. Proposing that successful adaption to climate change is not exclusively limited to exogeneous forces outside of its control (such as lack of available funding) but also by the values, perceptions, processes, and power structures in society. Four key elements emerged as major hinderances to successful climate adaption including the role of ethics, lack of precise knowledge, perceptions of risk, and undervaluing of place and culture. Given the diverse construct of human society, some communities may undervalue or overvalue the risk of climate change as well as the relative success or failure of climate adaption policies. Researchers conclude by suggesting that an adaptable society is characterized by awareness of diverse values, appreciation and understanding of specific and variable vulnerabilities to impacts, and acceptance of some loss through change. Aggarawal and Haglund (2019) put the social-ecological framework into practice through the development of a social-ecological services module to conduct a comparative analysis of

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water sustainability in two major megacities in the developing world: Sao Paulo, Brazil, and Delhi, India. From the analytic perspective, the module identified the need for better understanding of the diversity and sustainability implications for “settlements” that arise in cities in the global South. Coupling this classification of “settlements” with other subsystems, such as water infrastructure and water governance, not only affords decision makers a better understanding of the challenges in achieving universal water coverage both in terms of physical infrastructure and messy governance issues. Comparing the relative success of both cities in promoting greater water sustainability, researchers found that the mobilization of citizen groups and the networking of these individuals with key actors in state agencies was successful in obtaining universal potable water provisions for Sao Paulo, Brazil. Conversely, coordination for water rights was harder to manage in Delhi due in large part to its highly fragmented governance structure, lack of adequate funding, and poor communication with critical actors. As climate change continues to worsen extreme weather phenomena, such as extended periods of drought, modules such as these will become critical in assessing the feasibility of adaptive measures beyond the technical understanding through the consideration of the roles social systems play in promoting or hindering the measures success. Developing resource management strategies in the face of climate change is complicated by the uncertainty associated with projections of climate and its impacts and by the complex interactions between social and ecological variables. The broad nature of this challenge calls for the development of an integrated framework that integrates a variety of research tools that can support resource management decisions in the face of rising uncertainty. Miller and Morisette (2014) propose such a framework through the integration of three key methods of climate change assessment: species distribution modeling, scenario planning, and simulation modeling. While in the past each process has largely been utilized independent of the others, the researchers argue that incorporation of elements of all three best account for critical social and ecological dynamics while also considering future uncertainties. Scenario planning offers a more structured framework for developing scenarios across diverse groups and institutions while simulation models can assist in reproducing complex system dynamics associated with those scenarios. Species distribution models can help enhance simulation models through additional analysis of the complex relationship between climate, biophysical conditions, and species ranges. The use of all three methods serves as the one of the best systems for refining

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conceptualizations of social-ecological systems, engaging various stakeholders, and exploring

the effectiveness of climate related policy in future scenarios.

Food-Energy-Water (FEW) framework and planning for climate change

The Food-Energy-Water (FEW) nexus rests on the understanding that food security, energy security, and water security are all closely linked to one another and that any action taken in one area can have serious effects in one or both of the other areas. These connections lie at the heart of sustainable economic and environmental development and must be taken into consideration especially as burgeoning urban populations and climate change consequences threaten the stability of these linkages. Bieber et al. (2018) elaborate on this nexus through the development of an integrated modeling framework to optimize investment in both power generation and water infrastructure. Using a combination of socio-demographic, agent-based, and optimization modeling researchers found that the model was successful in allocating investments towards power and water infrastructure projects as supported by the inclusion of the modeling framework case study in Ghana. The inclusion of a food production forgone metric was also included in the optimization scenario as a means of assessing optimal land use practices. The framework's ability to simulate the effects of climate change, technology development and water scarcity-related policies on the power sector was also demonstrated within the Ghana case study. The effects of climate change were especially pronounced in Ghana’s power generation technology, highlighting the vulnerability of the nation’s power infrastructure. While development of frameworks to address the FEW nexus are complicated due to the complex nature of the industries involved, the development of integrated modeling techniques proves to be a beneficial tool in not only assessing the complexities between the three industries but in aiding future policy decision making, such as carbon-emission reduction

policies. Narrowing the focus of the FEW framework to sub-Saharan Africa, Ding et al. (2019) elaborates on the nexus by analyzing the interconnected role FEW resources, FEW services, and FEW health outcomes play in the overall success of the framework. Examining the FEW relationships in 28 sub-Saharan African nations (a region that faces significant resource insecurity) researchers determined that limited governance and socioeconomic capacity, rather than access to natural resources, more significantly impacted access to FEW services and health

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outcomes. Weak governance structures were found to be a significant determinant of FEW stability within the region with a significant impact on the water quality and associated health implications (ex: diarrhea linked deaths). FEWrelated health outcomes were also more strongly influenced by FEW services, with water and food access issues particularly impacting health in the sub-Saharan region. While more traditional academic literature specifically focuses on the relationship between and among the various dimensions of the nexus, inclusion of FEW services and related health impacts adds another dimension to the analysis of the framework and

its relationship to a dynamic and shifting environment. Sperling and Berke (2017) elaborate on the FEW framework further by including another element to the nexus through the inclusion of “X” or other systems (e.g., mobility). Proposing an “urban nexus science” (UNS) roadmap that explores the synergies, tradeoffs, and benefits of FEW systems for cultivating resilient and sustainable cities the researchers argue that the design, planning, and operation of FEW systems can be improved through integrated analyses that help to accelerate infrastructure, land use, and hazard mitigation planning. A push for system modeling and place-based approaches, new public- private partnerships, and business models is needed to best examine outcome and accelerate the implementation of desired FEW approaches. Inclusion of other elements (X) provide a more qualitative understanding of the FEW nexuses at large. While each of the three sectors may influence each other, their choices permeate beyond those confined boundaries and can have an effect on numerous conditions, including mobility, housing, communication, and waste. While this urban nexus science framework is a good start, it still remains largely theoretical and lacks

the case studies or implementation measures to validate its benefits.

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