It is quite possible than climate change will close down whole regions or countries on the planet. The process has started in northern Kenya already. Forecasts are, that by 2050, 200-700 million people will be forced to move to escape the impacts of climate change.
Many of these migrants will be shifting from rural to urban areas placing greater pressure on an urbanisation process that is forecast to accelerate in intensity regardless of climate change. At the end of 2008 one half of the world’s population lived in cities. By 2050 that figure will have increased to more than two-thirds.