Adaptation and Mitigation Strategies Against the Urban Heat Island Effect a Comparative Study on Amsterdam and Rotterdam
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Adaptation and mitigation strategies against the urban heat island effect A comparative study on Amsterdam and Rotterdam Author: Marijn Fennema ([email protected]) Student no. 11054670 Word count: 17301 Course name: Bachelor Scriptieproject Sociale Geografie en Planologie Bachelor Thesis Project Human Geography and Urban Planning Course no.: 734301500Y Coordinator: Drs. J. K. Maiyo Second reader: Dhr. J.V. Rothuizen Date: June 25, 2018. 0 Acknowledgements First of all, I would like to thank Drs. Josh Maiyo, my bachelor’s thesis supervisor for guiding me through the process of writing my thesis and doing research as a human geographer. He has also given me insight about what doing academic research is really like, which made me realize that although I will soon have my bachelor’s degree, I still have a lot to learn. Secondly, I would like to thank all the interviewees for helping me with my thesis by interviewing them, sharing information I would not have obtained otherwise. More specifically, I would like to thank Alexander Wandl and Jeroen Kluck for sharing their knowledge and insights about heat stress in the Netherlands. Besides that, I want to thank the people interviewed at the municipalities, municipal health services housing corporations for sharing their current views on the urban heat island effect as well as their strategies to cope with it. I would also like to thank De Groene Stad (the green city) for sharing their vision. Finally, I would like to thank my family, and my friends in particular for their support and positivity during the thesis writing process. 1 Abstract Background. Human interference with the climate system is occurring, which leads to changes in human and natural systems. These changes have caused impacts on natural and human systems around the globe in the past and will continue to do so in the future. One of these effects is the urban heat island effect, which is a phenomenon that occurs in urban areas, where the air temperature is usually higher than in the surrounding countryside. This is caused by three phenomena. The first being urbanization, population growth and urban sprawl, the second being more manufactured materials and the third being an increase in heating and cooling needs. The Netherlands has experienced negative effect from the urban heat island effect. The 2006 head wave for instance led to an estimated 1000+ fatalities in the Netherlands, for a large part those living in urban areas. Research goal. This research is aimed to find out the current situation of heat stress in the Netherlands, and Amsterdam and Rotterdam in particular. This study also looks into how Amsterdam and Rotterdam are trying to cope with heat stress and implementing adaptation and mitigation strategies. Research Methods. The urban heat island adaptation and mitigation strategies in Amsterdam and Rotterdam are researched by analyzing existing scientific literature as well as in-depth interviews with people that are linked to heat stress and the urban heat island. Results. Although heat stress does not receive the attention it deserves, heat awareness in both cities is rising at an institutional level, which could eventually lead to the implementation of more adaptation and mitigation strategies specifically aimed at reducing heat in cities. The public, on the other hand, does not seem to be aware of heat stress. Adaptation strategies against heat stress include the use of air conditioning and acting according to the national heat plan. Vegetation is the primary mitigation strategy in both cities in the outdoor space as well as applied on the built environment (mainly via green roofs). Many adaptation and mitigation strategies are applied through co-benefits strategies, are often (but not always) top-down and applied generically. Conclusion. When comparing the two municipalities in heat awareness, it seems that Rotterdam is more aware of the urban heat island and its implications than Amsterdam. This is on the levels of heat awareness, as well as heat-oriented adaptation and mitigation strategies. The key difference in adaptation and mitigation strategies is that Amsterdam is overall a greener city, and Rotterdam is applying more adaptation and mitigation strategies that are aimed at the urban heat island effect. The reason for this might be that in Rotterdam, there is more need for heat-specific adaptation strategies, because it can become warmer in summers due to Amsterdam being a much greener city Recommendations. This study recommends making more use of the polycentric approach in order to become resilient against the urban heat island effect, or resilient cities in general. Similar future research should include interviews with urban planners, urban architects and urban engineers, as well as interviewing or surveying residents to investigate public heat awareness. 2 Table of contents 1 Introduction 5 1.1 Research topic 5 1.2 Scientific relevance 6 1.3 Research questions 6 2 Theoretical framework 7 2.1 The urban heat island effect 7 2.2 Causes of the urban heat island effect 7 2.3 Adaptation and mitigation strategies 9 2.4 A polycentric approach to the urban heat island effect. 9 2.5 Urban Resilience 10 3 Operationalization 13 3.1 Heat awareness 13 3.2 Adaptation and mitigation strategies 13 3.3 Implementation of adaptation and mitigation strategies 14 4 Background 16 5 Study area 18 5.1 The Netherlands 18 5.2 Amsterdam 18 5.3 Rotterdam 20 6 Methodology 22 6.1 Research design 22 6.2 Data collection methods 22 6.3 Reliability and validity 23 6.4 Ethical considerations 23 6.5 Data analysis 24 6.6 Limitations 24 7 Results: heat awareness 25 7.1 Institutional awareness 25 7.2 Public awareness 27 7.3 Concluding remarks 28 8 Results: adaptation and mitigation strategies 29 8.1 Adaptation strategies 29 8.2 Mitigation strategies 33 8.3 Concluding remarks 36 9 Results: implementation of adaptation and mitigation strategies 37 9.1 Heat stress adaptation and mitigation as primary or secondary objective? 37 9.2 Policy: top-down or bottom-up? 38 9.3 Area-oriented or generic adaptation and mitigation? 39 9.4 Concluding remarks 39 3 10 Discussion 40 10.1 Co-benefits, the only way to adapt? 40 10.2 Rising heat awareness 40 10.3 Differences in adaptation and mitigation between Amsterdam and Rotterdam 41 10.4 A polycentric approach to the urban heat island effect? 42 11 Conclusion 43 12 References 45 13 Appendix 52 13.1 The heat stress framework by Hatvani-Kovacs et al. (2018) 52 13.2 Screenshots of the Extrema Rotterdam weather app 53 13.3 Infographic municipality of Amsterdam 54 13.4 Positions of the interviewees 55 4 1 Introduction 1.1 Research topic Urbanization is a rapidly growing form of land use change that is mainly driven by the population and the economy in a country (Ma et al., 2005). Although it is considered as an emerging phenomenon that can lead to many environmental problems in developing countries nowadays, urbanization has played a big role in the economic development of the now “developed” countries in the 20th century (Davis & Keating, 2015). One of the countries that has experienced rapid urbanization in the 20th century is the Netherlands. The number of urban inhabitants in the Netherlands has grown substantially over the past decades, with 59,8% living in urban areas in 1960 and 76,8% living in urban areas in 1990 (United Nations, 2014). According to the United Nations World Urbanization Prospects report (2014), the Netherlands is currently one of the world’s most urbanized countries, with 90,5% of its inhabitants living in urban areas (United Nations, 2014). This trend of urbanization is expected to continue until at least 2050, where an estimated 96,4% of the inhabitants in the Netherlands will live in urban areas, which will make the Netherlands the 13th most urbanized country in the world (United Nations, 2014). Almost one sixth of the Dutch population resides in Amsterdam and Rotterdam, the two largest cities in the Netherlands, with 1,1 and 0,9 million inhabitants living in both urban agglomerations respectively (United Nations, 2014). Urbanization can lead to various effects. These effects range from an increase in air pollution (Barbera et al., 2010) to an increase in surface temperature and a decrease in humidity (Wang et al. 2013). In the Netherlands, many cities have experienced expansion in the 20th century, which in many cases has led to urbanization-induced temperature increase (Koopmans et al., 2015). One of the most significant effects caused by urbanization closely related to urbanization- induced temperature increase is the urban heat island effect, which means that urban areas experience higher temperatures than rural areas (Peng et al., 2012). The urban heat island effect leads to higher surface temperatures due to mainly an increase of impervious surfaces, which is one of the effects of urbanization (Yao et al., 2017). The urban heat island effect is considered as a threat because of its many negative effects, the most substantial negative effect being the influence on human life by increasing the risk of exposure to health threatening heat (Zhou et al., 2015). This has led to an increase in mortality rates (Tan et al., 2010). The urban heat island effect is not a problem that only occurs in tropical climates. In fact, it also occurs in countries with a cooler climate like the Netherlands. Here, cities such as Rotterdam can experience an urban-rural temperature difference of 7 oC in the summer (Keuning, 2009). Although the urban heat island effect can lead to threatening situations for humans, there are many strategies that help to adapt or mitigate the urban heat island effect. This includes strategies such as increasing green areas and open spaces (Rushayati et al., 2016) or increasing the albedo (surface reflectivity) with the usage of reflective pavements (Synnefa et al., 2011).