The southwestern United States, the Iberian Peninsula and parts of the Middle East and other regions are at risk of seasonal water shortages resulting from decreasing snowfall in a warming climate.

Justin Mankin at Columbia University in New York and his colleagues looked at projections from various climate models to determine how warming might affect snowfall and river run-off in more than 400 large basins in the Northern Hemisphere. The team identified a dozen or so snow-sensitive basins that, across all climate models, face an 80–100% risk of declining water supply in the coming decades. Each of the sensitive basins has a current population of more than 1 million people — including the Rio Grande basin spanning Texas and Mexico, the Ebro–Duero basin in Spain and the Asi basin in Lebanon and Syria.

Environ. Res. Lett. 10, 114016 (2015)