Climate crisis has made summer drought 20 times more likely, scientists say | Drought

The climate crisis has made record drought in the northern hemisphere this summer at least 20 times more likely, scientists have calculated. Without human-caused global warming, the event would have been expected only once every four centuries.

The drought has affected agricultural production and electricity supply, exacerbating the food and energy crises already triggered by Russia’s war in Ukraine. Droughts will become even more severe and more frequent unless fossil fuel burning is phased out, the researchers warned.

The dry conditions, assessed using soil moisture data, were largely the result of heat waves that hit North America, Europe and Asia, with relatively less rainfall decline. important. Scientists have said a summer as hot as 2022 would have been “virtually impossible” without global warming and that in Europe alone there have been 24,000 heat-related deaths.

The analysis looked at conditions in the northern hemisphere, excluding the tropics, and in western and central Europe, where the drought was particularly severe and significantly reduced crop yields. The European summer was the driest on record dating back to 1950, while the northern hemisphere drought was the second driest on record, after 2012.

The dry conditions have caused widespread water shortages and wildfires, with a record number of fires in Europe, the first national drought alert in China and more than half of the United States declared drought. In the UK, temperatures reached 40C for the first time on recordshocking scientists and watering bans are still in place across much of the country.

“The summer of 2022 has shown how human-induced climate change is increasing the risk of drought in densely populated and cultivated regions,” said Professor Sonia Seneviratne, of ETH Zurich, Switzerland, and member of the analysis team. “We need to phase out the burning of fossil fuels if we want to [prevent] more frequent and intense droughts.

Dr Friederike Otto, from Imperial College London, UK, and also a member of the team, said: “Drought conditions in Europe have led to reduced harvests. This situation was particularly worrying as it followed a heat wave fueled by climate change in [India and Pakistan] it also destroyed crops and came at a time when world food prices were already extremely high due to the war in Ukraine.

Scientists had already discovered that the deadly South Asia heatwave made 30 times more likely by the climate crisis and that the intense rains, which caused devastating floods across Pakistan, has been worsened by 50% by global heating. In August, a analysis by the Guardian laid bare the devastating escalation of extreme weather events around the world, supercharged by human-caused climate change of just 1°C to date.

The drought study was carried out by an international team of researchers as part of the World Weather Attribution group. He analyzed soil moisture levels in June, July and August 2022 in the top meter of soil, where plants absorb water. The team used meteorological and soil data and computer models to compare the likelihood of summer drought in today’s warmed world and in a world without global warming.

Scientists have found that the record Northern Hemisphere drought of 2022 would be expected once every 20 years under the current climate, but only every 400 years without climate change. Drought in Western and Central Europe has been made at least three to four times more likely by global warming. But they said that doesn’t mean climate change has been less influential in Europe, because the footprint of climate change is harder to discern in smaller regions.

The analysis is complex and involves uncertainties, but the researchers said the study’s estimates are conservative, with the true influence of human activities likely even higher.

Professor Maarten van Aalst, director of the Red Cross and Red Crescent Climate Centre, said: “Climate change is hitting us really hard, not only in poor countries like Pakistan, but also in some of the poorest regions. richest in the world, such as central and western Europe. , which had been considered less vulnerable. It is playing out before our eyes even faster than we could have imagined.

“We are also seeing the impacts worsen and ripple across regions and sectors,” he said. For example, the drought reduced hydropower generation, as well as power from nuclear and coal-fired power plants, due to lack of cooling water. “It worsened a situation where electricity prices were already under pressure, due to the Russian-Ukrainian war and when we needed a lot of electricity for air conditioning across Europe to cope with the high heat.”

“This new study clearly points to the fingerprint of climate change and should be another wake-up call for reducing emissions, but also for investing more in resilience,” van Aalst said.

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