Period from 2024 to 2028 | 80% probability that the 1.5°C threshold will be temporarily crossed, warns the UN

(Geneva) The warning is “severe”: it is 80% likely that the average annual temperature of the globe will “temporarily” exceed pre-industrial levels (1850-1900) by more than 1.5°C for at least one over the next five years, the UN warned on Wednesday.


According to a bulletin from the World Meteorological Organization (WMO), coordinated with a speech by the UN Secretary-General in New York announcing the same figure at the same time, the world is moving “closer and closer” to the limits set in the The 2015 Paris Agreement, signed by almost every country on the planet.

The limit will be considered to have been reached when a warming of 1.5°C is observed on average over several decades, which is not yet the case; it is not impossible that next year will be colder than this year, etc.

In any case, it is even more likely (86%) that at least one of the next five years (2024-2028) will become the hottest on record, thus dethroning 2023.

And the probability that the average temperature over 2024-2028 will be higher than that of the last five years is 90%.

“The WMO is sounding the alarm, because we are going to temporarily exceed the threshold of 1.5°C more and more frequently,” declared the deputy secretary general of this specialized United Nations agency, Ko Barrett, in a communicated.

Taking into account the successive monthly records, the global average temperature of the last 12 months (June 2023 – May 2024) is thus the highest ever recorded, exceeding the pre-industrial average (period 1850-1900) by 1.63°C.

“Dark reality”

The probability of exceeding the 1.5°C threshold in any of the next five years has steadily increased since 2015, when it was close to zero. For the years between 2017 and 2021, this probability was 20%. It increased to 66% between 2023 and 2027.

It now reaches 80%.

“This is a severe warning,” writes the WMO.

“Behind these statistics lies a dark reality, we are far from achieving the objectives set in the Paris agreement,” said Ms.me Barrett, who does not lose hope: “temporary exceedances do not mean that the 1.5°C objective is definitively unattainable”.

The WMO estimates a 47% probability that the average global temperature over the entire period 2024-2028 will exceed pre-industrial values ​​by more than 1.5°C, while this probability was estimated at 32% last year. for the period 2023-2027.

This WMO bulletin is produced by the United Kingdom Meteorological Service (Met Office), which serves as WMO’s main center for annual to decadal climate forecasts. It synthesizes forecasts from 15 different institutes.


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