Northern Hemisphere’s extreme summer drought ‘virtually impossible’ without human-made climate change

CNN

By Christian Edwards, CNN

Drought across the Northern Hemisphere this summer — which scorched soil, dried up rivers and triggered mass crop failure — was made at least 20 times more likely by the climate crisis, a new analysis has found.

The research, published Wednesday by the World Weather Attribution initiative, found that without the climate crisis, the drought that hit swaths of North America, Asia and Europe this summer would historically be a 1-in-400-year event — meaning it was a drought that was so intense, it would only be seen once every 400 years on average.

But global warming caused by the burning of fossil fuels has made a drought of this magnitude a 1-in-20-year occurrence, the scientists found.

The soaring temperatures experienced this summer, which contributed to the drought and killed tens of thousands of people across Europe and China, would have been “virtually impossible” without climate change, the analysis also found.

The researchers used historical data, observations and scientific modeling, comparing conditions under today’s climate — which is around 1.2 degrees Celsius warmer than it was before industrialization — with the climate that preceded it, before the late 1800s.

“The 2022 Northern Hemisphere summer is a good example of how extreme events caused by climate change can also unfold over large regions in longer periods of time. It also shows how the combination of many different changes in the weather can damage our infrastructure and overburden our social systems,” Freiderike Otto, a climate scientist at Imperial College London and one of the study’s authors, said in a statement.

“In Europe, drought conditions led to reduced harvests. This was particularly worrying, as it followed a climate change-fueled heatwave in South Asia that also destroyed crops, and happened at a time when global food prices were already extremely high due to the war in Ukraine.”

While much of the hemisphere experienced below-average rainfall this year, the analysis found that increasing temperatures was the main driver behind the drought.

The scientists also noted their findings were conservative, and “the real influence of human activities is likely higher” than stated in the report.

Across the Northern Hemisphere this summer, extreme heat and low rainfall led to several unprecedented events: China issued its first-ever a national drought alert; the United Kingdom recorded its highest-ever temperature; Europe experienced its hottest summer; and the water crisis in the US West intensified, prompting new water usage cuts.

Alongside the immediate danger to life, the summer’s extreme heat posed severe threats to infrastructure, industry and food supply, fueling the ongoing cost of living crisis in many of the affected regions.

Europe was already battling geopolitical shocks to supply. This climate-induced shock has further “aggravated the cost of living crisis, compounding the impacts of the Ukraine war,” said Maarten van Aalst, another of the report’s authors and Director of the Red Cross Red Crescent Climate Center.

“We are witnessing the fingerprint of climate change not just in specific hazards,” van Aalst said “but also in the cascading of impacts across sectors and regions.”

What’s to come

Scientists are increasingly able to quantify the link between the climate crisis and extreme weather events. They can also more accurately make projections.

The Northern Hemisphere can expect extreme temperatures — like those experienced this summer — much more frequently, the analysis found.

“This result also gives us an insight on what is looming ahead,” said Dominik Schumacher, a researcher at the Institute for Atmospheric and Climate Science at ETH Zurich. “With further global warming we can expect stronger and more frequent summer droughts in the future.”

In this case, the water shortages, wildfires, crop failures, higher food prices and depleted electricity supply experienced over the past few months may become commonplace.

The study follows not only a summer of extreme weather but also a destructive hurricane and typhoon season. The death toll from Hurricane Ian in the US had surpassed 100. Typhoon Noru ripped across the Philippines recently, after rapidly intensifying from the equivalent of a category 1 hurricane to a category 5 in around six hours.

In November, world leaders will meet in Egypt for COP27, the UN Climate Change Conference, where extreme weather events this year will likely add to the urgency of discussions.

Sonia Seneviratne, also a professor at ETH Zurich, said: “We need to phase-out the burning of fossil fuels if we want to stabilize climate conditions and avoid a further worsening of these drought events, which will become more frequent and more intense with any additional increase of global warming.”

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