It is no longer a secret that summers are and will be increasingly drier and hotter across Europe. This summer has been good proof of that. In fact, excessive dryness and the heat wave In the second half of the 21st century, it will become increasingly intense, especially in southern EuropeAs Elfatih Eltahir, a professor of civil and environmental engineering at the Massachusetts Institute of Technology (MIT), predicted in his statements to the portal physics.org.
According to Eltahir, climate models predict dry summers in the south of the continent and also in the Mediterranean basin. hot spot -hotspot-, that is, one of the regions that will be most affected by droughts caused by climate change.
As the MIT professor recalls, heatwaves are particularly important in this panorama, an extreme phenomenon that Europe has experienced this summer, as well as in 2020, 2019, 2018, 2015 and 2003. A particularly urgent phenomenon in Southern Europe. But why?
The role of soil moisture
This area is located at the transition between the dry subtropics – the Sahara desert – and the relatively humid mid-latitudes, therefore high summer temperatures cause precipitation to evaporate quickly. This implies that soil moisture depends on the spring rains being consistent enough to withstand the summer months.
“A dry spring in Europe (as in 2022) results in dry soils in late spring and early summer.. This lack of surface water also limits surface evaporation in summer,” continues Eltahir.
This has two consequences: on the one hand, Since there is no water to evaporate on the ground, solar energy gradually increases the air temperature.. On the other hand, water ingress into the air layers near the surface is reduced, drier air is created and the possibility of precipitation is minimized.
“Unified, these two effects increase the likelihood of heat waves and droughts“Elfatih adds Eltahir.
However, as doctoral student Alexandre Tuel emphasized, spring precipitation is not the only factor. “It takes a spark to ignite the fuel. In Europe and elsewhere, that spark is provided by large-scale atmospheric dynamics.”
To explain this reflection, Tuel gives the example of an anticyclone coming over an area with very dry soils. “This coincidence will cause a rapid rise in surface temperature, leading to a heat wave that can last for weeks,” he says.
This is exactly why southern Europe and the Mediterranean region are favorite areas for heatwaves due to the vulnerability of spring precipitation.
Spring rains will continue to decrease
“This will play an increasingly important role in the future, because Spring precipitation is expected to decrease, making scorching summers even more likely in this corner of the world,” adds Tuel.
Regarding floods, Tuel acknowledges, they are a more difficult phenomenon to predict, as they affect a wide variety of factors and also depend heavily on atmospheric dynamics.
“What is almost certain is that with warming the water content in the atmosphere increases. So, if the dynamics are suitable for precipitation, most of the precipitation could fall into a warmer climate. For example, there was a flood in Germany last year. It is unprecedented that climate change has made it more likely,” Tuel said. concludes that it is caused by heavy rains”.
Reference article: https://phys.org/news/2022-10-europe-vulnerable.html
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