Persistent megadroughts will become a more prevalent feature of the global climate, according to a 40-year study released this week.
The Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL) said one of these droughts, in Chile, had been happening for 15 years.
This was the longest lasting period of drought in 1000 years, significantly impacting the country’s water reserves.
“This is but one blatant example of how the warming climate is causing multi-year droughts and acute water crises in vulnerable regions around the globe,” the study report said.
“However, droughts tend only to be noticed when they damage agriculture or visibly affect forests.”
The researchers analysed global meteorological data and modelled droughts between 1980 and 2018.
They found a “worrying increase” in multi-year droughts that “became longer, more frequent, and more extreme, covering more land”.
“Each year since 1980, drought-stricken areas have spread by an additional 50,000 square kilometres on average—that’s roughly the area of Slovakia, or the US states of Vermont and New Hampshire put together,” the report said.
“Megadroughts had the highest immediate impact on temperate grasslands. ‘Hotspot’ regions included the western USA, central and eastern Mongolia, and particularly southeastern Australia, where the data overlapped with two well-documented multi-year ecological droughts.”
The researchers said the long-term effects on the planet and its ecosystems from megadroughts remained largely unknown.
“Currently, mitigation strategies largely consider droughts as yearly or seasonal events, which stands in stark contrast to the longer and more severe megadroughts we will face in the future,” researcher Professor Francesca Pellicciotti said.
“We hope that the publicly available inventory of droughts we are putting out will help orient policymakers toward more realistic preparation and prevention measures.”
The full report is on the ISTA website.
