The month of September closed with intense rain levelsfrom Super Typhoon Yagi in Asia to Cyclone Helene sweeps the coasts of Floridabut the phenomenon cannot be attributed with certainty to climate change.
In several regions, early data shows that the amounts of water that have fallen from the sky are local records.
The rains that hit central and eastern Europe in mid-September are “by far the most intense ever recorded” in the region, reveals a study published Wednesday by the network of scientists World Weather Attribution (WWA).
In the Japanese city of Wajima, more than 120 millimeters of water fell in one hour on the morning of September 21, a record since measurements began in 1929.
However, although scientists are able to link some extreme weather events to climate change, it is still too early to draw definitive conclusions.
The European observatory Copernicus should have a global data compilation ready by early October.
“There have always been extreme weather events, but their intensity has been amplified by global warming, particularly in terms of precipitation,” Paulo Ceppi, of the Grantham Institute in the United States, told AFP on Thursday. Imperial College London.
“This is probably one of the indicators common to the phenomena observed in very different regions of the world,” he added.
Global warming has doubled the probability, compared to the pre-industrial era, of experiencing heavy rain for four days, according to the WWA network study.
More heat and more humidity?
“It is very difficult to attribute different phenomena that occur at the same time in the world to climate change,” says Liz Stephens, lead scientist at the Red Cross and Red Crescent Climate Centre, in statements to AFP.
“But the fundamental principle remains that for every additional degree Celsius, the atmosphere can accumulate 7% more humidity,” he continues.
As global warming is about to exceed 1.5 degrees Celsius compared to the pre-industrial era, “the calculation is quite fast: a significant impact will be obtained,” resumes Paulo Ceppi of the Grantham Institute.
In short, a warmer planet is also a rainier planet.
The summer of 2024 in the northern hemisphere has been the warmest ever recorded, surpassing the record of 2023, Copernicus reported.
The sweltering season around the Mediterranean “It generated a lot of additional evaporation, which caused a lot of humidity over Europe, a favorable terrain for all that humidity to be released in some places,” explains Paulo Ceppi.
“Global temperatures, both on land and in the oceans, were abnormally high in August-September despite the cyclical La Niña phenomenon“, which is generally associated with cooling, says Roxy Mathew Koll of the Indian Institute of Tropical Meteorology.
However, the scientist observes, this excess heat and humidity contributes to the “intensification” of storms.
