A new analysis commissioned by the United Nations uses a comprehensive combination of social, economic, political and environmental factors to identify areas around the world most at-risk for “hydro-political” strife. This river basins study was part of the U.N.’s Transboundary Waters Assessment Program.

Researchers from the United States, Spain and Chile took part in the analysis, which has been recommended by the U.N. Economic Commission for Europe as an indicator for the U.N.’s sustainable development goals for water cooperation.

Results of the study have just been published in the journal Global Environment Change.

The analysis suggests that risks for conflict are projected to increase over the next 15 to 30 years in four hotspot regions — the Middle East, central Asia, the Ganges-Brahmaputra-Meghna basin, and the Orange and Limpopo basins in southern Africa.

Whomever controls the water has enormous power over their neighbors. It’s a pretty terrifying situation when you think about it: just because your weird and arbitrary border has a river in it, you get to control the lives of people across that line? You can divert it, shunt it, dam it and drain it?

But really, that’s the way it always has been. America, of course, has its fair share of problems with that, like how we pretty much shut off the Colorado from Mexico (a situation that has been slowly and promisingly remediated, though no one knows what a Trump presidency will do to it).

That’s the way it has always been, sure, with resources being the reason for and tool of war, but that doesn’t mean we’re not entering scary new times. There are more people and less water. Climate change is going to be scything across the globe like a whirlwinded Queen of Hearts. Resources will be hoarded and dams will lead to war. An irrigation ditch can be a casus belli. We all know that in the 21st-century, water is war. But I don’t think people recognize just how hair-trigger and volatile it is going to be.

Think of how complex the Waukesha Diversion was. And how peaceful it was. Now imagine how difficult and fraught diversion negotiations will be when it is the life and death of a nation at stake. Think of how easy it will be to boil over into violence. Think of how that has happened in America’s past. That’s tomorrow’s world. Unless we actually come up with a legitimate mechanism for handling these situations, which means a de facto dissolving of some measures of national sovereignty, there is no chance.