The effects of urbanization and climate change are converging in dangerous ways. Cities are major contributors to climate change: although they cover less than 2 per cent of the earth’s surface, cities consume 78 per cent of the world’s energy and produce more than 60% of all carbon dioxide and significant amounts of other greenhouse gas emissions, mainly through energy generation, vehicles, industry, and biomass use.
At the same time, cities and towns are heavily vulnerable to climate change. Hundreds of millions of people in urban areas across the world will be affected by rising sea levels, increased precipitation, inland floods, more frequent and stronger cyclones and storms, and periods of more extreme heat and cold. In fact, many major coastal cities with populations of more than 10 million people are already under threat. Climate change may also negatively impact infrastructure and worsen access to basic urban services and quality of life in cities. In addition, most of the vital economic and social infrastructure, government facilities, and assets are located in cities. The most affected populations are the urban poor – i.e. slum dwellers in developing countries – who tend to live along river banks, on hillsides and slopes prone to landslides, near polluted grounds, on decertified land, in unstable structures vulnerable to earthquakes, and along waterfronts in coastal areas.
Despite these risks, many cities have not yet addressed climate change. The reasons include a lack of relevant city policies and action plans; existence of regulations on urban planning and environment which have not been adjusted to manage climate change; slow response to climate disasters due to lack of capacity and resources; and lack of public awareness on climate variability and climate change-induced hazard mitigation. However, when properly planned, capacitated, and managed through the appropriate governance structures, cities can be places of innovation and efficiency. Together with their local authorities, they have the potential to diminish the causes of climate change (mitigation) and effectively protect themselves from its impacts (adaptation).