The Environmental Challenge of Our Cities
With rising affluence and rapid
urbanisation, the energy and climatic, as well as, health
impacts of cities are of increasing importance. Much of this intensive urban
growth is in the hot climate developing countries, not least in Asia. The quest for ‘sustainable
’ cities has led to innovative and successful solutions that offer better living quality along with greatly reduced environmental impacts. Due partly to a lack of resources, less has to date been done in developing countries and hot climates. The largest energy and climatic challenge in these cities is that of cooling.
Our urban environment determines indoor climate and
wellbeing, as well, as outdoor comfort and public
health.
Whereas tackling the issue of heat in cities is our focus, sustainable
development is essentially about quality of life, for both people and for the environment, both now and in the future. Seen as a whole—which it must be—the aim is a good balance between all three areas of ecology, economy and society. In the real world, however, economic and socio-political factors often weigh more heavily in decision making than environment. This represents missed opportunities, where growing cities are locking themselves into poor
health as well as huge future energy and climate burdens. Yet many sustainable solutions exist already, and do not even necessarily cost more. This applies equally in the field of cooling.
Hot-climate cities are increasingly problematic due to congestion, pollution and deteriorating
microclimates, not least growing urban
heat island (UHI) effects (Santamouris 2007). As is well known, inner city temperatures are commonly several degrees hotter than the surrounding countryside; leading to increased energy needs for cooling, as well as heat stress and indeed mortality. Global warming and rapid
urbanisation both exacerbate overheating in cities. In this book, we focus on case studies from Asian hot climates because projections suggest they will be subjected to more land degradation, population displacement and economic disruption from climatic changes (including sea level rises) than any other part of the planet (Anthoff et al. 2006; USAID 2010). Our selected region is thus the most vulnerable to climate change and temperature increase. A
megacity like Manila in the Philippines has already reached the danger level of 2 °C increase in its urban core—the increase to be avoided as part of the 2015 Paris climate agreement. Hence, we face a major challenge for both existing and new cities, and particularly for the
urban poor who cannot afford better living environments or cooling amenities.
There is abundant research, as well as experience, about energy, transports, pollution, green
buildings and other specific urban environmental topics. Much of it is addressed by specialists, one issue at a time. Our aim is to highlight the whole picture and address the issue of urban cooling in an interdisciplinary way not often found in practice but essential for sustainable outcomes. This book is, therefore, addressed to a wide readership of designers, urban planners, energy planners, city authorities and policymakers. It highlights a multidisciplinary perspective and the potential of integrated methods towards urban cooling.
Millions are moving to live in often mediocre or poor urban conditions. These new city dwellers comprise three main groups: those at the bottom of the pyramid in informal settlements,
slums or low quality urban
housing; a large, upwardly mobile low- to middle-income group; and a small well-off group at the top. Whilst all are important, it is in this large middle group that energy use
is rising very rapidly, as they acquire amenities including air
conditioning (and cars). In addition, in developing countries the buildings, vehicles and amenities these households obtain are seldom of high efficiency. Therefore, there is an ever-growing need to inform policy makers, developers, planners, designers and consultants of related sectors.
Today’s rising climate emissions correspond broadly to rising energy use
; this coupling will continue as long as energy supplies are largely fossil fuel based, and most projections suggest that, in 2050, two-thirds or more of global energy use
will still be oil, coal and gas (US Energy Information Administration 2016). Three main solutions are available to us: conversion to renewables
, energy efficiency, and downscaling or behavioural changes
. Downscaling is most applicable to the rich, and is directly energy and cost saving; but people in developing countries are relatively poor and still need more, not less, basic energy amenities. Energy efficiency is often the cheapest technical option, but is not easy to achieve in developing countries due to lack of technology, resources, institutions or all three. Renewables
for their part are spreading, but not fast enough to mitigate climate emissions alone. Whilst all three avenues are important, this book focuses on the task—which is preventative, and largely free—of environmentally skilful planning of cities and their overall energy systems. We do not address details of the many specific technologies, such as air conditioning
or desiccant cooling. Technology is—if anything—the easier part. Sustainable design of cities can greatly reduce their needs for energy, whatever the technology; including for cooling.
Existing cities face the huge task of restructuring for sustainable
development; new
megacities have the opportunity to ‘get it right’ first time. But their rapid growth combined with a lack of resources often leads to poor solutions. Rapid growth is problematic in itself, frequently being at the expense of local environments and of living quality: ‘Hong Kong’s first large-scale
sustainability research initiative (Barron and Steinbrecher 1999) has revealed the astonishing deterioration of the environment. The main environmental problems are associated with over-concentration due to high-rise and
high-density development, and include poor air quality, water depletion, noise, and excessive waste production’ (Zhang 2000). It often implies hasty, poorly prepared and controlled urban development. The field of energy is one example; even in countries, such as, Thailand
and China
, where adequate skills and planning systems exist, it has often been seen as too early to impose strict requirements for energy efficient buildings
—which might hamper growth. To do so, in poorer regions of Asia, or Africa
, is even less realistic. Hence, many cities are heading for huge future energy use
and emissions, as well as, hot and unhealthy living environments.
References
Anthoff, D., Nicholls, R. J., Tol, R. S. J., & Vafeidis, A. T. (2006). Global and regional exposure to large rises in sea-level: A sensitivity analysis. Working paper 96. Tyndall Centre for Climate Change Research, Norwich.
Barron, W., & Steinbrecher, N. (1999). Heading towards sustainability? Hong Kong: Centre of Urban Planning and Environmental Management, University of Hong Kong.
Santamouris, M. (2007). Heat Island research in Europe, state of the art. Advances in Building Energy Research, 1, 123–150.Crossref
US Energy Information Administration. (2016, May). World energy outlook 2016. USDOE, Washington, DC.
USAID. (2010). Asia Pacific regional climate change adaptation assessment: Final report findings and recommendations. Washington, DC: USAID.
Zhang, X. Q. (2000). High-rise and high-density compact urban form: The development of Hong Kong. In J. Jenks & R. Burgess (Eds.), Compact cities, sustainable urban form for developing countries (pp. 244–254). London/New York: Spon Press.