Science

Hotter summers are baking the water out of soil at unprecedented rates

Summer 2022, like the one before it and the one before that and the one before that one, was hot and dry across the Northern Hemisphere. This year, there were water shortages, droughts, wildfires, and crop losses around the world, and they show no signs of stopping. A new report from the World Weather Attribution initiative says that climate change and global warming are making events these severe droughts at least 20 times more likely than they were just a century ago.

Scientists from Switzerland, India, the Netherlands, France, the United States, and the United Kingdom, collaborated on this report to gauge the extent that human-induced climate change has changed both the likelihood and intensity of the low soil moisture, both at the surface and the root zones for most crops. According to the study, this summer’s heatwaves and lack of rain led to very dry soils, particularly in central European countries like France and Germany, as well as mainland China. These deficits in soil moisture led to an increase fire risk, and poor harvests that has led to already high food prices that further threatens food security around the world.

[Related: How climate change fed Pakistan’s devastating floods.]

According to the study, the main driver of these droughts was extreme heat in most of the Northern Hemisphere. They said it would be “virtually impossible” for to see such high average temperatures over such a large area without the influence of greenhouse gas emissions.

“In many of these countries and regions, we are clearly, according to the science, already seeing the fingerprints of climate change,” Maarten van Aalst, the director of the Red Cross Red Crescent Climate Center and one of 21 researchers who prepared the new study, told The New York Times. “The impacts are now very clear to people, and they’re hitting hard,” he added.

According to the National Oceanic and Atmospheric Administration (NOAA), almost half of the lower 48 states experienced moderate to extreme drought in 2022 and parts of the Southwest and California are stuck in a two decade megadrought.

In Europe, record heat began to blanket the continent in May, drying up rivers and causing massive fires. The European Union estimates that heatwaves may have added 11,000 excess deaths in France and 8,000 in Germany.

[Related: The biggest tool we have to fight climate anxiety is community.]

China faced its most brutal summer since modern records began in 1961. The dry and hot weather reduced hydropower output, forcing the country to burn more coal to keep its factories running, emitting more greenhouse gasses.

In September, scientists with World Weather Attribution said that climate change also likely worsened this summer’s devastating floods in Pakistan. The floods have damaged two million homes, submerged about one-third of the country, and caused 1,600 deaths. The initiative geared at doing rapid analysis of weather events also found that global warming had made July’s record-shattering heat wave in Britain hotter and more likely to occur in the future.

One of the report’s most central findings about the planet’s Northern Hemisphere is that because the planet has already warmed by 2.2 degrees Fahrenheit (1.2 Celsius) since the late Nineteenth Century, this summer’s low moisture levels in the first few feet below the soil was at least 20 times as likely to occur compared. This part of the soil is crucial since it’s where the root systems of main plants draw water.

According to Friederike Otto, a scientist at Imperial College London and another one of the study’s authors, natural variations in the weather in Central and Eastern Europe can cancel each other out since it is a smaller area than the Northern Hemisphere above the tropics.

“There is absolutely no doubt that climate change did play a big role here,” Otto said in an interview with The New York Times. But, she continued, “the exact quantification of that role is more uncertain for soil moisture than, for example, when we look at heavy precipitation.”



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