Global temperatures remain above 1.5°C

Global temperatures remained at historically high levels in April, continuing a nearly two-year streak of unprecedented heat on the planet, which is stirring the scientific community regarding the pace of global warming.

Globally, April 2025 is ranked the second warmest after April 2024, according to the European observatory Copernicus, which bases its data on billions of measurements from satellites, weather stations, and other tools.

Last month extends an uninterrupted series of record or near-record temperatures that has lasted since July 2023, soon approaching two years. Since then, with one exception, every month has been at least 1.5°C hotter than the pre-industrial era average (1850-1900). Many scientists had anticipated that the 2023-2024 period — the two hottest years ever measured globally — would be followed by a respite when the warmer conditions of the El Nino phenomenon would fade. "With 2025, it should have settled down, but instead, we remain in this phase of accelerated warming," said Johan Rockström, director at the Potsdam Institute for Climate Impact Research in Germany. "It seems that we are stuck here" and "what explains this is not entirely resolved, but it's a very worrying sign," he told AFP.

The past two years "have been exceptional," Samantha Burgess from the European center operating Copernicus told AFP. "They remain within the range that climate models predicted for today, but we are at the top of the range."

One explanation is that the La Nina phenomenon, the opposite of El Nino and synonymous with cooling influence, has turned out to be only "weak in intensity" since December, according to the World Meteorological Organization, and could already decline in the coming months.

Almost 1.4°C already

A group of about fifty renowned climatologists, led by Briton Piers Forster, estimate that the climate was already warmed by an average of 1.36°C in 2024. This is the conclusion of a preliminary version of their study that annually updates the key figures from the Intergovernmental Panel on Climate Change (IPCC), the climate experts mandated by the UN. Copernicus has a current estimate very close to that, at 1.39°C. The 1.5°C warming threshold, the most ambitious of the Paris Agreement, is on the verge of being reached in a stabilized way, calculated over several decades, many scientists estimate. Copernicus believes that this could be the case by 2029.

"That's in four years. The reality is that we are going to exceed 1.5°C," says Samantha Burgess.

"At the current pace, the 1.5°C will be surpassed before 2030," also estimates Julien Cattiaux, a climatologist at the CNRS contacted by AFP. "It is said that every tenth of a degree counts," as it multiplies droughts, heatwaves, and other weather catastrophes "but currently, they are happening fast," the scientist warns. But "now, what we must try to do, is to have global warming as close as possible" to the initial target because "it's not the same if we target a climate warmed by 2°C at the end of the century or by 4°C," he recalls.

That the burning of fossil fuels — coal, oil, and gas — is responsible for the bulk of the warming is not debated among climatologists. But discussions and studies are multiplying to quantify the climatic influence of changes in clouds, a decrease in air pollution, or the Earth's ability to store carbon in natural sinks such as forests and oceans. Annual records of global temperatures go back to 1850. But ice cores, ocean floor sediments, and other "climate archives" establish that the current climate is unprecedented for at least 120,000 years.