By 2099 the world is expected to be on average between 1.8ºC and 4ºC hotter
than it is now. Large areas are expected to become drier—the proportion of land
in constant drought expected to increase from 2 per cent to 10 per cent by 2050.
Meanwhile, the proportion of land suffering extreme drought is predicted to increase from 1 per cent at present to 30 per cent by the end of the 21st century. Rainfall patterns will change as the hydrological cycle becomes more intense. In some places this means that rain will be more likely to fall in deluges (washing away top-soil and causing flooding).
According to Nicholls and Lowe (2004), using a mid-range climate sensitivity
projection, the number of people flooded per year is expected to increase by between 10 and 25 million per year by the 2050s and between 40 and 140 million per year by 2100s, depending on the future emissions scenario (Source-IOM)