‘Climate Whiplash’ Tests Four Corners Communities’ Ability To Adapt — KUNC #ColoradoRiver #COriver #aridification

Mancos and the Mesa Verde area

From KUNC (Luke Runyon):

Communities in the Four Corners — where the borders of Colorado, Utah, New Mexico and Arizona meet — have been bouncing between desperately dry and record-breaking moisture since the winter of 2017, forcing people dependent on the reliability and predictability of water to adapt…

If you want a sense of what climate change is doing to agriculture in the Southwest, and how individuals are reacting to unprecedented weather, this is a good place to see those effects on a small scale.

“We’ve set records almost every year, good or bad,” [Dustin] Stein said. “So hot, so dry. So much snow, the river’s too high. It’s just incredibly bipolar.”

The winter of 2017-2018 was one of the driest ever recorded in parts of the Four Corners, kicking off the latest intensification of a prolonged dry period that’s stretched nearly two decades. Rivers ran at some of their lowest flows ever recorded during their annual spring runoff in 2018.

That summer was the hottest on record across most of the Colorado Plateau. From October 2017 to September 2018, the region recorded its driest weather in more than a century of recordkeeping…

Stein draws irrigation water to grow forage for his cattle from the Mancos River, a tributary of the San Juan River. It’s a key water source for the ranchers and farmers in this agricultural valley. The river used to be reliable, Stein said.

“We’ve got fairly senior water rights in the Mancos Valley. Our water hadn’t gone off until 2002. Since 2002 it’s gone off almost every year at some point in the year,” Stein said.

With irrigation water tapped out in the summer of 2018, and his pastures turning brown, Stein made the expensive decision to send all his cows and their calves to high mountain pastures owned by a custom grazing operation 200 miles to the north, near Gunnison…

Stein thought he was out of the woods as this snow started flying at the start of this past winter. At its height in the spring, snowpack in some parts of the nearby San Juan mountains was at its highest level ever, compelling parched communities to quickly prepare for flooding…

The spigot turned off this again summer, when the above-average heat and below-average moisture trend returned. Drought conditions have been slowly worsening in the Four Corners region since late July…

This feeling that Stein is talking about, of being jerked around, lurching from one small weather-related crisis to the next, has a name, according to Gregg Garfin, climatologist and researcher at the University of Arizona.

“Some scientists and practitioners have referred to this as climate whiplash,” Garfin said…

They found strong evidence of rising temperatures. That finding alone causes a sort of domino effect, where the warmer temperatures upend the accumulation and timing of snowpack melting. That can then lead to a mismatch between a runoff period and when water users, like cities and ranchers, need it. The higher temperatures also sap more moisture from the region’s already arid soil, and pull more water from rivers and reservoirs in the form of evaporation. When precipitation does arrive, it’s less effective than it used to be.

“Then if you combine that with some kinds of disturbances, such as tree mortality like we’ve seen, mortality in ponderosa pine, piñon-juniper woodlands, and also fires,” Garfin said. “Those things can reset ecosystems.”

A woodland might come back as a shrubland. Or a shrubland might return as a grassland. Or a grassland might turn into a desert.

San Juan River Basin. Graphic credit Wikipedia.

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