Scientists warned that Climate change will exacerbate the threat of Megadroughts. This was revealed in a report titled Assessing the risk of persistent drought using climate model simulations and paleoclimate data published in September 2014 issue of American Meterological Society’s Journal of Climate. The lead author of the study is Dr Toby Ault.
The report is the first to scientifically establish that climate change exacerbates the threat of Megadroughts.
The term megadrought is generally used to describe the length of a drought, and not its acute intensity. In scientific literature the term is used to describe decades-long droughts or multi-decadal droughts.
They have historically been associated with prolonged La Niña conditions, which create cooler than normal water temperatures in the tropical eastern Pacific Ocean. This reduces evaporation and, in turn, the amount of rainfall.
Threats of Megadroughts
Experts warned that the droughts could be even more severe than the prolonged water shortage currently afflicting California. In California, residents have resorted to stealing from fire hydrants amid mass crop failures and regular wildfires.
Megadroughts will become considerably more frequent as global warming increases temperatures and reduces rainfall in regions already susceptible.
Without climate change, there would be a 5 to 15 per cent risk of a megadrought in the south-west of the US this century. With it, the probability jumps to between 20 per cent and 50 per cent, with the southernmost part of the country particularly at risk.
The threat megadroughts poses is so great that it could decimate the world’s economy and food supply, inflicting a humanitarian crisis.
Effects of Megadroughts
Megadroughts have occurred periodically around the world in the past few thousand years. In some cases it had caused civilisations to collapse, such as the ancient Puebloan native-American tribes in the south-west of the US. They abandoned their homes during a megadrought in the late 13th century and the Khmer empire of Cambodia 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.
Global Warming susceptible to droughts
Global warming will make droughts evermore 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.
Scientists warned that the continued global warming could lead to multiple regions experiencing a hot megadroughts at the same time in the future. This could lead to global economic, food and humanitarian shocks.
Who: Scientists warned
When: 17 September 2014