Is the lousy weather the fault of global warming?

This post is taken from the newsletter “Human warmth”sent every Tuesday at 12:30 p.m. Every week, journalist Nabil Wakim, who hosts the Chaleur Humaine podcast, answers questions from Internet users on the climate challenge. You can register for free by clicking here.

Question of the week

“Hello, I am not at all climate skeptic, but I have difficulty understanding whether or not the rotten weather of recent months is linked to warming. It’s rained a lot and it’s already cold, is it the warming fault, or does it invalidate what the scientists say? » (question asked by Marin at chaud [email protected])

My response: It’s painful, but I have to answer both yes and no. Yes, disruptions to the water cycle linked to climate change are causing more intense rainfall. On the other hand, the fact that it is sometimes warmer, sometimes colder – like the last few days – is simply due to natural variations in the climate. And also: it does not change the validity of scientific studies, which are confirmed every day by the facts.

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 disruption of the water cycle. When the air is warmer, it can hold more water in the form of vapor. (If you’re interested, it’s a law of physics known as the Clausius-Clapeyron formula). However, this water vapor which 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, then periods with equally more intense rain. This is exactly what has happened in a large part of France in recent years, with a very severe drought in 2022 and 2023, and very heavy rainfall in 2024 – with flooding in Hauts-de-France by 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 might receive roughly the same amount of rain on average over the year, but they will no longer be distributed in the same way: longer periods with little precipitation, interrupted by episodes of intense rain.

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