Scientists: Be prepared for ‘megadroughts’

WASHINGTON: Climate change is set to unleash a series of decades-long "megadroughts" this century, according to research to be published this week.
Experts warn the droughts could be even more severe than the prolonged water shortage currently afflicting California, where residents have resorted to stealing from fire hydrants amid mass crop failures and regular wildfires.
Megadroughts – which are generally defined as lasting 35 years or more – will become considerably more frequent as global warming increases temperatures and reduces rainfall in regions already susceptible, warns Cornell University's Dr Toby Ault, the author of the new report.
Megadroughts are also likely to be hotter and last longer than in the past, he claimed.
His peer-reviewed research – to be published in the American Meterological Society's Journal of Climate – is the first to scientifically establish that climate change exacerbates the threat.
"We can now explicitly add megadroughts to the list of risks that are being intensified by climate change. Without climate change, there would be a 5% to 15% risk of a megadrought in the southwest of the US this century. With it, the probability jumps to between 20% and 50%, with the southernmost part of the country particularly at risk," Ault told The Independent.
The threat megadroughts poses is so great they could decimate the world's economy and food supply, inflicting a humanitarian crisis, experts warned.
"Global warming will make droughts ever more severe and devastating in the future. The south-west of the US, southern Europe, much of Africa, India, Australia and much of Central and South America could all have a drought that lasts decades," Jonathan Overpeck, an environmental scientist at the University of Arizona, said.
"It is feasible that continued global warming could lead to multiple regions experiencing a hot megadrought at the same time in the future. This could lead to global economic, food and humanitarian shocks."
Megadroughts have occurred periodically around the world in the past few thousand years. In some cases they have caused civilisations to collapse, such as the Puebloan native American tribes in the southwest of the US – who abandoned their homes during a megadrought in the 13th century – and Cambodia's Khmer empire in the 14th century.
The fallout from future megadroughts will be even more severe because the global population is larger and the strain on water supplies is greater, said Prof Park Williams of Columbia University in New York.
"Many of the drought-prone parts of the planet will see megadroughts in this century that are far worse than anything in the past several thousand years." – The Independent