The year 2024 has become the first on record to be more than 1.5°C warmer than the pre-industrial average, according to a study by an Austrian-German team of experts, published in the Nature Climate Change journal.

The research suggests there is a more than 99% chance that this marks the beginning of a long-term trend of similar warming.

‘Drastic Cuts’ in Emissions Needed

To keep within the targets of the 2015 Paris Agreement, greenhouse gas emissions must be reduced rapidly and significantly, the researchers warn.

Using computer models, they analysed various emissions scenarios to assess whether a single year of 1.5°C warming signals the start of a 20-year period with the same average temperature rise. Under the most likely scenario – where efforts to cut emissions continue at a moderate pace – this outcome is “practically certain”, says Emanuele Bevacqua from the Helmholtz Centre for Environmental Research in Leipzig.

With stronger action to curb emissions, the probability of already having entered a 20-year period of 1.5°C warming could be lowered to 75%.

‘Not an Isolated Case’

Recent temperature trends suggest 2024 will not be a one-off.

“The first years with temperature increases of 0.6 to 1°C also consistently fell within the first 20-year periods in which such average warming levels were reached,” said Carl-Friedrich Schleussner from the International Institute for Applied Systems Analysis (IIASA) in Austria.