The drought experienced in Europe, North America, China, and other regions in the Northern Hemisphere in the summer of 2022 will be 20 times more likely due to human-induced climate change, according to a new study by the World Weather Attribution, informs The Guardian.
This is part of the emerging field of Extreme Event Attribution, which aims to answer to what extent extreme weather or climate-related events are influenced by climate change. The World Weather Attribution, a collaboration between climate scientists from different research institutions around the world, has developed methods to do extreme event attribution quickly but thoroughly.
Last summer heat waves and low rainfall were common across the Northern Hemisphere, leading to very dry soils and significant impacts such as water shortages, increased risk of forest fires, and disruption of power generation and commercial navigation in inland waterways. The resulting decreases in crop yields and energy generation exacerbated the social and economic impacts of already high food and energy prices.
It is estimated that the persistent heat led to over 24,000 fatalities across Europe, and more than 770.000 hectares of land had burnt throughout the European Union by September 24, which equals nearly three times the average for 2006-2021.
Researchers assessed the extent to which climate change affected the likelihood and intensity of low soil moisture, looking at the soil surface and the root zone, in two regions: the North Hemisphere excluding the tropics, and West-Central Europe, from June to August 2022.
Low soil moisture conditions such as those observed this past summer are expected to happen once in 20 years in both regions, according to observation-driven land surface models. To assess the role of climate change, the observation-based datasets were combined with climate models. Researchers also assessed the role of climate change in temperature and rainfall, finding that the high temperatures were the main reason for the increased drought.
For the Northern Hemisphere not including the topics, the study found human-induced climate change made soil moisture drought more likely by a factor of at least 20, for the root zone soil moisture, whereas in West-Central Europe climate change made the root zone soil moisture drought about 3-4 times more likely. This does not mean that climate change had less of an influence in Europe, but that it is more difficult to ascertain that influence in smaller regions.
Such a hot summer would have been virtually impossible without climate change, the study said; in fact, this type of drought is expected to happen only once every 400 years across the Northern Hemisphere, were it not for climate change.
Looking into the future, soil moisture drought is expected to continue to increase with additional global warming, a finding consisted with projected trends in climate models. “This new study clearly points to the fingerprint of climate change and should be another wake-up call to reduce emissions, but also to invest more in resilience,” said Prof Maarten van Aalst, director of the Red Cross Red Crescent Climate Centre, involved in the study.
