Just consider some statistics. It’s estimated some one point four million people move to cities every week. And by 2050, we will add nearly 2.5 billion people to the planet, with 90 percent of the urban growth in that time taking place in developing countries.
Yet living in cities can be risky business. Many large cities are coastal, in deltas or on rivers and at risk from of flooding from powerful storms or rising sea levels. Globally 80 percent of the world’s largest cities are vulnerable to severe earthquakes and 60 percent are at risk from tsunamis and storm surges.