The heat is on to ensure sustainable development in Asia's swelling cities

Julian Hunt and Yuguo Li from The Guardian




As countries make final preparations for this month’s UN summit in New York to agree the post-2015 development agenda, there is a growing need for policies that take an integrated approach to climate change and urban crises. Ground zero is Asia, where 60% of the world’s population live.

Asia’s conurbations are transforming faster than ever, with their geographies and populations doubling in less than 10 years. As the continent consumes ever-greater natural resources and discharges more waste, cities are generally not able to keep air pollution levels within international health standards. There is now a greater incidence of illness and death among the elderly and vulnerable, including young children.



Furthermore, many Asian – and also African – cities are losing the vital contribution that green spaces make to public health, despite studies showing that parks and roadside trees are cost-effective measures against high temperatures, pollution and flooding. In Nigeria, Lagos has lost most of its central green areas, but in China, Beijing is now planting huge tree belts alongside major arteries.

As urban areas expand, data and computer models confirm how their environmental effects, including rainfall and air pollution, extend hundreds of kilometres further away. Moreover, with energy use by transport, housing and industry in urban areas responsible for more than half the global consumption of carbon-based fuels, large cities are driving greenhouse gas emissions and consequent rises in global average temperatures.

Asia’s growing urban areas are increasingly affecting the climate and environment of the whole world, with serious consequences for the long-term wellbeing of populations everywhere.

Within Asian cities near the equator, wind speeds are generally low, and they are steadily decreasing as urban areas expand, so that as global temperatures rise, they do so even faster in high-rise city developments, as studied in Hong Kong. However, climate change and urbanisation also increase the risk of very cold weather, as well as more extended periods of great heat.



Extraordinary phenomena are already being observed in inland urban areas in winter months. For instance, high concentrations of urban and rural aerosols are increasingly preventing the sun’s rays reaching the ground, even causing small rivers to freeze in Delhi last year. This is affecting the economy as winter transport is sometimes severely disrupted – not only aircraft, but even trains and road traffic.

These urban crises are coinciding with natural disasters. Already, more than 90% of people affected by natural disasters – floods, cyclones, earthquakes, drought, storm surges and tsunamis – are in Asia.

This is a particular problem in south-east Asia, especially the Philippines capital, Manila, which has a worsening atmospheric environment and suffers from heavy rain, mudslides, high winds and flooding in coastal areas and inland. These problems are magnified by the growing number of people living in vulnerable locations, for example next to streams, or on hillsides.

Future planning has to factor in trends showing how 100-year peak rainfall rates have doubled, while their frequency has also increased. In Malaysia, Kuala Lumpur has unique, dual-use vehicle tunnels, which are converted to huge drains when floods occur. With global warming making the atmosphere more humid, the severity and frequency of these floods is only likely to increase.



Technology is helping people to prepare for intense urban rainfall, with radar systems tracking clouds and forecasting hours in advance. Some communities are also evacuating flood-prone areas and moving populations to public refuge buildings, which are being repositioned using models of how floods build up in these areas.


Similar public sheltering facilities are being used during warm temperatures, or periods of high pollution. Although many lives have been saved, unless infrastructure is improved the impact of extreme hazards will keep growing.



Various relevant policies were discussed two months ago at a meeting of the Asian Network of Climate Science and Technology and the Beijing Association of Science and Technology.

Some far-sighted planning policies also aim to reduce the growth of large cities by creating separate new towns from between 50km and 100km away. China has just commenced its plan for integrated development of the Beijing-Tianjin-Hebei area (the so-called Jing-Jin-Ji region of 130 million people), and neighbouring areas will take over many administrative functions from Beijing.

These, and other planning policies, could reduce emissions and pollution in these satellite cities as commuting distances for car drivers are reduced. Limiting mega-city growth should also moderate the rise of peak urban temperatures.



The take-up of practical policies across Asia depends on high-level advocacy for integrated policies tackling urban crises and climate change. This needs to be combined with “bottom-up” advocacy for mitigating measures such as the preservation of green areas; greener construction with less concrete; and enhanced public transport.

Coordinating global and regional policies should be a major theme not only at the New York conference on development issues, but at the UN’s landmark climate change summit in Paris in December. Specifically, the critical issues in cities have to be dealt with through regional collaboration so that effective energy and environmental measures are implemented in both urban areas and the surrounding regions.

Collaboration and joined-up thinking are critical to ensure that Asia is able to reduce carbon emissions, raise standards of global health and achieve economic sustainability.