As warming continues, ‘hot drought’ becomes the norm, not an exception

This article discusses the impact climate change is having on water resources.

The signs of rising temperatures are obvious across New Mexico right now, from the mountains to the river valleys, and from rangelands to suburban backyards.

“Climate change for the Southwest is all about water,” said Jonathan Overpeck, who has spent decades studying climate change and its impacts in the southwestern United States. Warming affects the amount of water flowing in streams, and the amount of water available to nourish forests, agricultural fields and orchards. There’s also the physics of the matter: A warmer atmosphere holds more moisture, demanding more from land surfaces. Plants need more water, too. “Any way you look at it,” Overpeck said, “water that normally would flow in the river or be in the soil ends up instead in the atmosphere.”

Past southwestern droughts were notable for declines in precipitation. But today’s droughts are different, he explained.  Even in wet years, which will still occur as the climate changes, warmer conditions dry out the landscapes.

“With atmospheric warming, we’re getting what we’re calling ‘hot droughts’ or ‘hotter droughts,’” he said. “That means that they’re more and more influenced by these warm temperatures, and the warm temperatures tend to make the droughts more severe because they pull the moisture out of plants, they pull the moisture out of rivers and out of soil—and that moisture ends up in the atmosphere instead of where we normally like to have it.”

Comments are closed.