Tiempo Climate Cyberlibrary

Urgent action is needed in urban centres in Africa, Asia and Latin America to adapt to climate change. Such centres house three-quarters of the world's urban population and will house most of the world's population growth in the next few decades. They include most of the cities at greatest risk from the increased intensity of storms, flooding and landslides that climate change brings.

Most greenhouse gas emissions are generated from the processes that serve wealthy urban consumers, most of whom are in high-income nations. Less carbon-intensive urban lifestyles are needed, including energy-efficient buildings, transport and production systems.

Cities in less wealthy nations have much lower emissions per person than wealthier nations, and adaptation to reduce risks from climate change impacts is more important. However, the development pathways of the nations that achieve economic success in this group and of the larger population nations will significantly affect future emissions so cannot be ignored.

Cities in poorer countries have a large and growing proportion of the world's population most at risk. Countries like India, China, Bangladesh and Vietnam have large urban populations in low coastal zones vulnerable to sea-level rise and storms. Coastal cities will also suffer from rising water tables undermining building foundations, saltwater contamination of groundwater, and damaged coastal tourism infrastructure and beaches. Many inland cities are at risk from flooding and mudslides. Glacial retreat will reduce water availability for many urban centres. Most cities will experience more heatwaves and air pollution, and warmer temperatures will extend the range of some diseases and increase risks from diarrhoeal diseases. Many city economies will suffer as agriculture in surrounding areas is affected.

Well-governed cities can reduce these risks, but in most African and Asian cities, 33 to 50 per cent of people live in illegal settlements that lack good water and sanitation provision, paved roads and storm drains. Many settlements are on risky sites such as floodplains, coastal areas or unstable hillsides. Their inhabitants have limited capacity to invest in adaptation and city governments often refuse to work with them.

Most urban governments lack the competence and capacity to act on climate change and have huge infrastructure backlogs. But there are good reasons for taking action. Much adaptation is making cities work better for low-income groups - ensuring their homes and settlements have good provision for water, sanitation and drainage and that they can get land for housing that is not on risky sites. Unfortunately, too many city policy makers see climate change as an environmental issue of little importance. And too many climate change specialists don't understand what constrains effective local adaptation.