Climate change and water …. Another climate change study is projecting declines in runoff in many parts of the West, a scenario that would put more pressure on the region’s water supplies. LA Times reports – NAEE series continues.
The reasons involve more than a drop in precipitation — which is actually expected to increase in some areas that are critical to Western water supplies. Rather, rising temperatures will cause greater evaporation from plants and the ground, reducing soil moisture and water runoff into rivers and streams.
The 10% drop in Colorado River flows would be on a par with the worst droughts recorded on the river in the last century, though it is less severe than the 12th century megadrought revealed by tree-ring studies.
“It may not sound like a phenomenally large amount, except the water and the river is already over-allocated,” said climate scientist Richard Seager, the paper’s lead author. The Colorado’s flows have proven to be less than thought when the river’s supplies were divvied up among California and the other six basin states in 1922.
In the Colorado headwaters region, average precipitation is expected to increase in all seasons, but greater evaporation will reduce soil moisture in the spring, summer and fall.
Central and Northern California and Nevada should get more precipitation in the winter but both states will get less the rest of the year. Coupled with more evaporation, that will result in an overall drop in runoff and soil moisture.
Though climate change simulations have grown more sophisticated, the authors noted that global models still can’t fully account for the West’s complex topography — and how it influences regional climate patterns.
- Climate Change Could Cut Western Water Runoff by 10% Los… (underpaidgenius.com)
- Researchers use IPCC AR5 models to forecast 10% drop in Colorado River flow in next few decades (greencarcongress.com)
- Smaller Colorado River projected for coming decades, study says (esciencenews.com)
- Study: Colorado River flows could decline by 10 percent as rainfall patterns shift and temperatures rise in the Southwest (summitcountyvoice.com)
- Southwest will have less surface water over next decade, says study (rawstory.com)
- Warm Weather, Population Growth May Shrink Colorado River by 10 Percent, Study Predicts (naturenplanet.com)
- Southwestern areas of the United States, reeling from its worst drought in 50 years, may have 10 percent less surface water within a decade (familysurvivalprotocol.com)
- The Stream, December 27: Evaporation to Exacerbate Western Water Shortages (circleofblue.org)
- Colorado River Flow Likely to Decline by 10 Percent in Next Few Decades: Study (natureworldnews.com)