FOCUS – Human-induced global warming remains the main driver of extreme temperatures recorded on the surface of continents and oceans.
Even hotter than 2023: the Climate Change Service (C3S) of the European Copernicus Observatory confirms this Friday January 10 that 2024, with its share of records and disasters, is indeed the first year beyond the bar of 1, 5°C of warming, the long-term limit set by the Paris agreement.
An unprecedented crossing of the threshold of +1.5°C
The symbolic bar of 1.5°C of warming compared to the pre-industrial period corresponds to the most ambitious limit of the 2015 Paris agreement. The latter in fact aims to contain warming well below 2°C and to continue efforts to limit it to 1.5°C. However, according to the C3S, which is based on the ERA5 atmospheric reanalysis system, last year, the global average temperature of 15.10°C exceeded the 1850-1900 temperature estimate by 1.6°C. designated as the pre-industrial level. Let us remember, however, that the Paris agreement refers to long-term trends: the average warming of 1.5°C must be observed over at least twenty years to consider the limit crossed, recalls the European service.
Credit: C3S/ECMWF.
Every month from January to June 2024 has in any case been warmer than the corresponding month of any previous year on record. In addition, a new record for daily average temperature was reached on July 22, 2024, with 17.16°C.
A real long-term trend
The trend is very real and global: 2024 was the hottest year for all continents, except Antarctica and Australia. « Human-induced climate change remains the main driver of extreme air and sea surface temperatures, while other factors, such as the El Niño Southern Oscillation (editor’s note: a natural meteorological phenomenon which corresponds to a warming of the waters of the tropical Pacific)also contributed to the unusual temperatures observed during the year »notes the C3S. Globally, the last ten years (2015-2024) are all in the top ten hottest on record. « The future is in our hands – rapid and decisive action can still change the trajectory of our future climate »reacted in a press release Carlo Buontempo, director of Copernicus.
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A heat record in the oceans
The average annual sea surface temperature also broke a record, with 20.87°C, 0.51°C higher than the 1991-2020 average. The European service also recalls that the extent of sea ice in the Arctic and around Antarctica « is a key indicator of the stability of the Earth’s climate », but last year, this extent of sea ice was significantly below average. In Antarctica, it reached record or near-record low values for the second year in a row.
Credit: C3S/ECMWF
An atmosphere loaded »
Global warming increases the capacity of the atmosphere to absorb water: according to the Clausius-Clapeyron formula, each additional degree increases its maximum water content by 7%. Last year, this total quantity of water vapor in the atmosphere reached a record level with around 5% more than the 1991-2020 average, says the C3S. The European service adds that « this abundance of humidity amplified the potential of extreme precipitation. In addition, associated with high sea surface temperatures, it has contributed to the development of major storms, including tropical cyclones. »
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Finally, in 2024, atmospheric concentrations of carbon dioxide and methane, the two main greenhouse gases responsible for global warming, have continued to increase. They reached record annual levels with respectively 422 parts per million (ppm) and 1897 parts per billion (ppb).
Exceptionally high costs
Natural disasters aggravated by climate change led to exceptionally high economic losses last year, reinsurer Munich Re said on Thursday. 2024 ranks 3rd costliest year since 1980, with insured losses amounting to 140 billion dollars, according to the reinsurer cited by AFP. Total economic losses stood at $320 billion, compared to $268 billion in 2023, the Bavarian group calculates, an increase of 19%. « Our planet’s weather machine shifts into high gear »declares Tobias Grimm, chief climatologist of the group, in the study.
