There is an 80 percent chance that the American Southwest and the central Great Plains will experience a 35-year “megadrought” before this century is over, according to a new study published in the journal Science Advances.
Scientists from NASA, Columbia University and Cornell contributed to the study, pointing to global warming as the chief factor in this upcoming disaster. Rising temperatures due to the greenhouse effect will result in both less precipitation and more evaporation for these North American regions, already notable for their relative dryness.
Following the hottest year in its recorded history, California is now in the fourth year of an exceptional drought. Researchers from Stanford University have partially attributed the state’s lack of precipitation to a high atmospheric “blocking ridge” that refuses to dissipate over the northeastern Pacific. This ridge is diverting high speed air currents that would normally flow over the west coast to deliver rain and snow. Stanford’s climate models show that this “Ridiculously Resilient Ridge” is three times more likely to develop in present atmospheric conditions compared to pre-industrial conditions.
In other words, the excess greenhouse gases produced by industrial emissions are influencing the drought.
The new study, led by Benjamin Cook, a scientist at NASA’s Goddard Institute for Space Studies in New York, states that even if countries reduce their emissions to “middle-of-the-road” targets, a 35-year or longer drought is still 60-70 percent likely to hit the Great Plains before 2100. However, even a middle-of-the-road scenario does little to affect the Southwest’s fate. The chances of a megadrought in that region remain nearly 80 percent.
According to the U.S. Drought Monitor, 11 of the last 14 years have seen drought in some part of the American West. As witnessed in California, the drought has a range of impacts across the state – even apart from communities requiring fresh water trucked in. It hits the state’s agriculture, its economy and its ecosystem, raising the prices of goods and increasing the risk of wildfires.
The research team used 17 models of drought and three models of soil moisture to calculate their results. Using data from tree rings going back about 1,000 years, they found that a megadrought struck the region in the 1100s and 1200s, but it pales in comparison to what’s coming.
“Even when selecting for the worst megadrought-dominated period, the 21st-century projections make the megadroughts seem like quaint walks through the Garden of Eden,” study co-author Jason E. Smerdon of Columbia University’s Lamont-Doherty Earth Observatory said in a statement.