Climate change has the potential to cause unprecedented damage to urban areas — both in terms of human life and financial capital. What will cities do to cope with rising sea levels, heatwaves, droughts and more frequent and severe storms? How will they protect their populations and economies? Cities are, in fact, uniquely placed to answer these questions. City mayors are often more able than nationally elected politicians to take decisive action on environmental initiatives, making many cities pioneers in adapting to climate change. CNN has teamed up with The C40 Cities Climate Leadership Group and the Carbon Disclosure Project to show the risks climate change poses to five major global cities and the steps they are taking to protect them for future generations.