Future Cities and Environmental Sustainability Saffa Riffat, Richard Powell and Devrim Aydin*
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Riffat et al. Future Cities and Environment (2016) 2:1 DOI 10.1186/s40984-016-0014-2 REVIEW Open Access Future cities and environmental sustainability Saffa Riffat, Richard Powell and Devrim Aydin* Abstract Massive growth is threatening the sustainability of cities and the quality of city life. Mass urbanisation can lead to social instability, undermining the capacity of cities to be environmentally sustainable and economically successful. A new model of sustainability is needed, including greater incentives to save energy, reduce consumption and protect the environment while also increasing levels of citizen wellbeing. Cities of the future should be a socially diverse environment where economic and social activities overlap and where communities are focused around neighbourhoods. They must be developed or adapted to enable their citizens to be socioeconomically creative and productive. Recent developments provide hope that such challenges can be tackled. This review describes the exciting innovations already being introduced in cities as well as those which could become reality in the near future. Keywords: Future cities, Sustainability, Urbanisation, Environment, Innovations Introduction factor, which even the excellence of Khmer engineering Throughout history, cities have been at the heart of hu- was unable to counter. man development and technological advancements [1]. Tenochtitian, the Aztec capital in what is now Mexico, Although an element of planning can be discerned even was built in a lake bordered by swamps. The flow of in the earliest cities they have often evolved in response water was controlled to provide land for building and ir- to the changing needs and aspirations of their inhabi- rigate fields, the so-called floating gardens. The city dis- tants. Some cities have survived for millennia, including tricts were connected by both causeways and canals. Rome, Athens, Cairo, Alexandra, Baghdad and Beijing, The Aztec engineers also had to separate the brackish and are still flourishing. Other, once mighty, cities have water of the lake from spring water from nearby hills for disappeared, their ruins being unearthed by present-day drinking. In 1519, at the time of the Spanish conquest, archaeologists. A fascinating example, built by the Tenochtitian, with an estimated population of 200,000 Khmer civilisation, is Ankor Wat [2] in present day to 300,000, and was one of the largest cities in world. Al- Cambodia, which boasted features very relevant to the though conquered it did not collapse like AnkorWat, design of future cities. Notable achievements by the an- but was developed by the Spanish into what is now cient Khmer engineers were the control and distribution Mexico City, with a population of 21 m. of water through a sophisticated canal system irrigating Although in designing cities of the future we have a agriculture within the city bounds supplying citizens much greater range of technologies than our ancestors, with ample food. The fundamental problems that the we must not make the hubristic mistake of assuming Khmer solved were the prevention of flooding by that these will ensure our success. The words of George Monsoon rains, and storing water for the subsequent Santayana are apposite, “Those who do not remember the periods of drought. Despite its success over 8 centuries, past are condemned to repeat it.” We need an enlight- AnkorWat collapsed in 1431 [3]. Climate change resulting ened approach to design cities of the future, learning in extended droughts is considered to be a contributory from the experience of the past and applying the ad- vanced technologies of the present. * Correspondence: [email protected] Department of Architecture and Built Environment, University of Nottingham, University Park, Nottingham NG7 2RD, UK © 2016 Riffat et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Riffat et al. Future Cities and Environment (2016) 2:1 Page 2 of 23 Tomorrow’s cities: chaotic or strategic? Lessons Table 1 Impacts of global urbanisation and mitigation from the immediate past strategies First and foremost, future cities must serve their citizens, Impacts Mitigation Strategies combining increased prosperity for all with desirable life High traffic density ✓ Efficient public transport styles. These aims must be achieved without detriment to ✓ Compact city design people who live in other regions; for example they must High amount of waste ✓ Recycling not export carbon emissions by importing goods manufac- Urban warming ✓ Increasing green space, tured by fossil fuel and feedstock dependent processes or ✓ Using reflective materials create pollution elsewhere. This is not to say that a city Increasing Air pollution ✓ CO2 capture, cannot import feedstock or energy intensive goods from ✓ Filtering exhaust gases, ✓ Increasing efficiency of industrial outside its borders; rather the energy and material con- processes/vehicles tents of imports must be balanced by those of exports. To Increasing energy ✓ Using renewable sources, this end, future cities must adopt wide scale utilisation of consumption/sinking ✓ Achieving low energy buildings, renewable energy, waste management/minimisation, water resources ✓ Increasing efficiency of devices/ harvesting/recycling, landscape/biodiversity to enhance the processes natural environment, use of green transport systems, Lack of biodiversity/natural ✓ Increasing green space, ✓ applications of innovative material/construction methods habitat Developing animal/plant protection areas (low/zero carbon buildings) and local food production. Sinking water resources ✓ Water purification While such aspirations would have been familiar to city ✓ Desalination designers in antiquity, their modern counterparts can ✓ Rainwater harvesting draw upon newer technologies such as integrated smart Rising food demand/ ✓ Vertical farming management control systems based on wireless sensor poverty ✓ Artificial food production networks, which by detailed monitoring can turn wasteful ✓ Greening the deserts cities into sustainable cities. Technologies will need to Land shortage for housing ✓ Constructing multifunctional be tailored to particular geographic, climatic and cultural buildings, ✓ Creative architectural designs conditions, but all will have a similar philosophy of turn- Weak Social cohesion ✓ Improving sociocultural environment ing buildings from passive entities to active, adaptive and ✓ Increasing the number of organisations- adaptable spaces that takes advantage of the surrounding events that bring people together environment for heat, cooling, light and electricity. A key to achieving low carbon cities is understanding how best to select and integrate various technologies from the many food buyers; and food demand will have to be met by available, to optimise performance for different building rural and peri-urban areas or by food imports. types, climates, cultures and socio-economic conditions. On the other hand, in many emerging cities, people A strategic approach will be required to achieve a sustain- are obligated to live in more marginal regions. They have able city to ensure that it functions efficiently as a whole. less adaptive capacity, low incomes and no assets. Add- But the planning parameters should not be so centralised itionally less legal and financial protection, no insurance, and rigid that they do not allow different community de- no land tittle… Indeed urban areas are more attractive signs and architecture styles to find expression. than rural areas for many people in terms of job oppor- Several impacts of overpopulation in urban areas are tunities, improved living conditions, multicultural envir- already appreciable as summarized in Table 1 with pos- onment and dynamic life. In fact developed countries sible mitigation strategies. First of all concerns of food are already highly urbanized due to the opportunities and water security is arising in many cities. As these cit- they have, and the United Nations estimates that the ies expand, agricultural land is converted into residential urban populations of Africa, Asia, and Latin America and industrial areas. For instance in Conception, a Chilean will double over the next 30 years, from 1.9 billion in City with a population of 500.000, 1734 hectares of 2000 to 3.9 billion in 2030. At that point, over 60 % of wetlands and 1417 hectaresofagriculturallandand the world's population will live in cities [5]. forests were transformed into residential areas between Cities with the growing urban mass will turn to a more 1975–2000 [4]. In Accra, Ghana, it is estimated that resource, land, food and energy demanding consumers 2600 hectares of agricultural land is converted every and they should be productive to be genuinely sustain- year where Chinese and Indonesian cities have the able. Unproductive urban areas will probably face with similar pattern [4]. In the future agriculture will be poverty, inequality of individuals, pollution, illnesses and challenged to meet the demand of a population that is external economical dependency. projected to grow and to urbanize. This indicates that Productivity is clearly desirable in emerging cities as more food will be demanded