In the past few days, large areas of the European continent have witnessed heavy rains, which caused floods that swamped many cities in Germany and Belgium in particular, killing dozens of people, and inflicting great material losses.
This extreme weather phenomenon has raised questions about the factors that led to its occurrence and its relationship to the climatic changes that the world is witnessing.
Weather fluctuations over Europe due to the “cold drop” phenomenon on July 15 (Ventusky app)
Cold drop and soil saturation
This heavy rain that falls on part of Europe is due to the "cold drop" phenomenon, which is unusual at this time of year over Europe, and occurs when hot air isolates a mass of cold air at high altitudes from the atmosphere above low This leads to strong and continuous rain at the local level.
According to some media reports, the amount of rain water that fell in some places reached 150 liters per square meter in just 24 hours.
What made matters worse was the occurrence of landslides after the soil was saturated with water and its inability to absorb more of it, which increased the severity of the torrential rains and the rise in the level of rivers.
A number of climate experts described what happened as shocking in terms of the intensity of the rains, the floods they caused and the heavy loss of life and property.
L'enroulement nuageux autour de la goutte froide, peu mobile et centrée sur l'Allemagne, est bien visible sur l'animation satellite.
L'air chaud/humide s'y enroule depuis l'est de la mer Adriatique en revenant par le nord sur Belgique et nord-est de la France pic.twitter.com/4hagteSdGY
— Alexandre Flouttard (@stormchaser_a81) July 15, 2021
Slower and stronger storms وأ
Many evidence points to the main role played by global warming in the occurrence of such phenomena. A warmer atmosphere contains more water and can cause heavy rains.
It also indicates that in the future, climate change will lead to more severe storms across Europe and around the Mediterranean basin.
A new study by researchers from Newcastle University has found that climate change is driving a significant increase in severe storms in the future.
By studying how climate affects severe rainstorms across Europe, climate experts have shown, according to a press release posted on the university's website, that there is an expected significant increase in slow-moving rainstorms in the future.
The results of the study published in the journal "Geophysical Research Letters" (Geophysical Research Letters) concluded that storms that produce heavy rain will move more slowly with climate change, and this increases the duration of these extreme phenomena.
The researchers say that semi-constant or slow rainstorms are currently uncommon in Europe and rarely occur over parts of the Mediterranean, but are expected to occur more frequently in the future.
The researchers, who used detailed climate simulations, found that slower storm movement would increase the amount of precipitation that accumulates locally, increasing the risk of flash floods across Europe beyond what was expected in previous studies.
Slow-moving storms will be 14 times more frequent by the end of the century over Europe and the Mediterranean basin (AGU website)
More frequent in the future
Scientists estimate that these slow-moving storms will be 14 times more frequent by the end of the century over Europe and the Mediterranean basin.
This type of storm is characterized by its very high cumulative capacity in precipitation and its devastating effects, as happened in Germany and Belgium.
Researchers expect that severe and slow-moving storms will cover the entire continent in the summer by 2100, and that the Mediterranean will witness more of this type of storm, especially in October and November, which leads to an extension of the peak storm season every year. .
According to the authors of the study, the main reason for the increase in the frequency and intensity of rainstorms is the decrease in temperature variation between the poles and the tropics, a decrease that weakens the winds in the upper layers of the atmosphere in autumn.
The researchers say that the results of this study, along with the current floods in Europe, confirm the importance of producing and managing improved emergency warning systems, and the application of climate change safety factors in infrastructure designs to make them more robust in the face of severe weather events, and also show the dangerous effects that can be expected. If greenhouse gas emissions are not curbed.