Droughts in Northern Hemisphere at least 20 times more likely due to climate change: study

With temperatures reaching record-breaking heights throughout the Northern Hemisphere and Europe over the summer, scientists estimate that climate change is making soil moisture droughts up to 20 times more likely, resulting in crop failures, water shortages, and reduced electricity supply.

Led by researchers with ETH Zurich, also known as the Swiss Federal Institute of Technology, an international team of climate scientists looked at soil moisture levels throughout June, July and August in order to better understand which agricultural regions experienced severe drought or substantially reduced crop yields.

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“The 2022 summer has shown how human-induced climate change is increasing the risks of agricultural and ecological droughts in densely populated and cultivated regions of the North Hemisphere,” Sonia Seneviratne, professor for land climate dynamics at ETH Zurich, said in a news release.

According to researchers, drought conditions similar to those experienced this summer can be expected once every 20 years in today’s climate. However, without human activity contributing to climate change – such as the burning of fossil fuels – drought conditions in the Northern Hemisphere would only be anticipated approximately once every 400 years or less.

Their study, published by the World Weather Attribution, tracks the impact of extreme weather events on agricultural and ecological regions, weighing the potential threat towards crop production and food security. Dryness was measured in the top metre of soil called “the root zone” – the fertile layer where plants extract water – and agricultural areas were evaluated amidst record-breaking heatwaves.

Scientists behind the study said rising temperatures were a key factor in increasing the risk of agricultural and ecological drought risks.

“The results of our analysis also give us an insight on what is looming ahead,” Dominik Schumacher, one of the researchers, said in the release. “With further global warming we can expect stronger and more frequent summer droughts in the future.”

According to the study, climate change rocketed temperatures to such an extreme that it would be “virtually impossible” to reach such heat without human-induced factors.

Given the impact of human activity on climate change, Seneviratne is calling for a reduction in global greenhouse gas emissions.

“We need to phase-out the burning of fossil fuels if we want to stabilise climate conditions and avoid a further worsening of such drought events,” she said.