Water, a third of river sub-basins at risk by 2050 - Earth and Poles. One-third of the world's river subbasins, the smallest units into which river basins are divided, will face severe clean water shortages by 2050.
The threat comes above all from pollution due to nitrogen, widely used for example in agriculture as a fertilizer, and looms large in particular in Central Europe, North America, southern China and Africa. In 2010, more than 980 river subBasins had little water, but more than 2,500 had high levels of pollution, and therefore contained little clean, usable water.