This post is taken from the newsletter. “Human warmth”sent every Tuesday at 12:30 p.m. Every week, journalist Nabil Wakim, host of the Chaleur Humaine podcast, answers questions from Internet users about the climate challenge. You can register for free by clicking here.
Question of the week
“Hello, I am not at all skeptical about the climate, but I am having a hard time understanding whether or not the bad weather in recent months is related to warming. It has rained a lot and it is already cold, is it the fault of warming or does it invalidate what scientists say? » (question asked by Marin at chaud humaine@lemonde.fr)
My answer: It’s painful, but I have to answer both yes and no. Yes, climate change-related disruptions to the water cycle are causing more intense precipitation. On the other hand, the fact that it is sometimes warmer and sometimes colder, as in recent days, is simply due to natural variations in the weather. And furthermore: the validity of scientific studies, which are confirmed every day by facts, does not change.
1/Climate change causes more intense rains
The term “global warming” does not reflect one of the most problematic realities of rising temperatures: a strong alteration of the water cycle. When air is warmer, it can hold more water as vapor. (If you’re interested, it’s a law of physics known as the Clausius-Clapeyron formula.) However, this water vapor that accumulates in the atmosphere is then transformed into rain.
In a warming world, we should expect to experience longer and more intense periods of drought, and then periods of equally more intense rainfall. This is exactly what has happened in much of France in recent years, with a very severe drought in 2022 and 2023 and very intense rainfall in 2024 (with flooding in Hauts-de-France, for example). We could summarize it by saying that global warming causes dry extremes and wet extremes.
Which allows me to point out that averages are often misleading! For example, a region may receive approximately the same amount of rain on average throughout the year, but it will no longer be distributed in the same way: longer periods with little precipitation, interrupted by episodes of heavy rain.
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