[ad_1]
Boise – According to a study, climate change could cause decades of mega droughts in the United States. Global warming has increased the risk of extreme events, researchers Mohammad Reza Alizadeh of McGill University and Mojtaba Sadegh of Boise State University explained in the journal. Scientific advances. Such long dry spells also existed in the United States in the 12th and 13th centuries.
Dozens of fires have raged on the west coast of the United States since mid-August. In California alone, about 19,000 first responders fought more than two dozen major fires. The flames have destroyed more than 5,800 buildings since mid-August.
As climate change progresses, it is more common for extreme events like heat waves and droughts to occur at the same time, the researchers said. His study focuses on this coexistence of drought and heat over the past 122 years. “Extreme hot and dry spells are the recipe for large wildfires,” said Mojtaba Sadegh. “These extremes are intensifying and expanding at unprecedented spatial proportions, making today’s wildfires possible along the entire west coast of the United States.”
Devastating effects also of shorter periods of drought
Even shorter periods of drought that lasted less than a decade, such as the American drought known as the “Dust Bowl” in the 1930s, could have devastating effects if they coexisted with heat. Among other things, climatic events in the atmosphere and on the ground could lead to such extremes in their interaction, according to the study. Scientists suspect that the determining factor for simultaneous periods of drought and heat in the recent past is primarily excessive heat. In the “Dust Bowl” period, however, the lack of precipitation was the main trigger.
A mega-drought is often preceded by a large area of high pressure, creating clear conditions that allow warm air to enter. Dry soils increase the proportion of heat in incoming sunlight, which affects the ambient temperature, according to the article. This has the consequence that heat waves intensify.
The researchers cite as an example the heat wave in Russia in 2010. The probability of a mega heat wave increased by a factor of 13 due to the interaction of drought and heat. The interaction of dry soil and warm air prevents cloud formation, which means less rain and, as a result, intensifies the drought, the researchers explained. (WHAT / dpa)
