Warming temperatures and uncertain rainfall mean if more isnt done to slow climate change, droughts lasting 35 years could blight western states, study says
The harsh drought currently gripping California may appear trivial in the future as new research shows that the south-west US faces the looming threat of megadroughts that last for decades.
California is in its sixth year of drought, which was barely dented by rains brought by the El Nio climate event and sparked a range of water restrictions in the state. But warming temperatures and uncertain rainfall mean that if more isnt done to slow climate change, droughts lasting 35 years are likely to blight western states by the end of the century, according to the study, published in Science Advances.
Such a megadrought would impose unprecedented stress on the limited water resources of the parched US south-west, researchers found, bringing conditions similar to the 1930s dustbowl to California, Nevada, New Mexico, Colorado and Utah but over a lengthier period.
Using a combination of temperature and precipitation models, the study predicts a 70% chance of a megadrought by the end of the century, should rainfall levels remain the same, with a 90% chance of an elongated drought should rainfall decrease, as most climate models forecast.
We cant rule out there could be a 99.9% chance of a megadrought, which makes it virtually certain, said Toby Ault, a scientist at Cornell University and lead author of the study.
Imagine if the current drought in California lasted for another 30 years. There may be a few decent years of rain here and there, but that would be a megadrought and it would certainly change peoples attitude to water. Taking a long-term view, we need to change our expectations of water in the west.
Megadroughts of 35 years are currently rare and have led to severe upheaval in the past. Theres evidence that the Pueblo people of what is now the south-west US were forced to abandon settlements in the 13th century due to a lengthy drought. The Sahel drought in Africa that ran into the 1980s also fits the definition of a megadrought.