A forthcoming water crisis could affect one in 10 people by the end of this century, found a study published today in the Proceedings of the National Academy of Sciences. As the planet warms, researchers expect to see as much as a 40 percent increase above current levels of what’s known as absolute water scarcity.

The scarcity won’t just arise from population growth, the researchers say. There will be more people, but they’ll be competing for fewer resources - brought about by changes in rainfall and evaporation tied to climate change. Their findings are based on the prediction that Earth will warm 3 degrees Celsius (5.4 degrees Fahrenheit) above pre-industrial levels by 2100 (the U.N. projects that the world will surpass 2 degrees warming by that time).

Absolute water scarcity is defined as having fewer than 500 cubic meters (132,000 gallons) of water available per person, per year (the global average is 1,200 cubic meters; it’s much higher in industrial nations). Areas under those conditions require extremely efficient management techniques for using and conserving their limited supply of water - which, as the researchers point out, many countries do not currently have in place.

Drought conditions also pose a threat to agriculture; as […]