Selon l'ONU, il y a 1 chance sur 2 que le seuil de +1,5°C soit dépassé dans les 5 ans

Selon l’ONU, il y a 1 chance sur 2 que le seuil de +1,5°C soit dépassé dans les 5 ans

CLIMATE – There is a one in two chance that the average annual global temperature will temporarily be 1.5°C higher than pre-industrial values ​​for at least one of the next five years, the UN said on Tuesday (May 10).

A temporary crossing of this threshold over a year is not, however, synonymous with a lasting overrun of this threshold, in the sense of the Paris Agreement on climate change. This agreement aims to contain the increase in the global average temperature to well below 2 degrees Celsius compared to pre-industrial levels and if possible to 1.5 degrees.

According to a new climate bulletin published on Tuesday by the United Nations World Meteorological Organization (WMO), the probability of a temporary exceedance of the 1.5°C threshold has increased steadily since 2015, year when this risk was close to zero.

For the years between 2017 and 2021, the probability of exceedance was 10%. It has increased “to almost 50% for the period 2022-2026″, indicates the WMO. But there is only a small probability (10%) that the five-year average exceeds the threshold of +1.5°C.

“This study shows, with high scientific reliability, that we are getting significantly closer to the moment when we will temporarily reach the lower limit of the Paris Agreement. The 1.5°C figure is not a randomly chosen statistic. It indicates the point at which the effects of climate will be increasingly harmful for people and for the entire planet,” explained WMO Secretary-General Petteri Taalas.

“As long as we continue to emit greenhouse gases, temperatures will continue to rise. At the same time, our oceans will continue to warm and acidify, sea ice and glaciers will continue to melt, sea levels will continue to rise, and extreme weather will continue to intensify,” he said. he warned.

He pointed out that the warming of the Arctic is “particularly marked”, even as the conditions prevailing in this region have repercussions for the entire planet.

Hottest year?

According to this bulletin on annual to decadal climate forecasts on a global scale, produced by the United Kingdom Met Office (Met Office), which is WMO’s main center for this type of forecast, it is very likely ( 93%) that at least one of the years between 2022 and 2026 becomes the hottest on record.

This record is currently held by the year 2016, which was marked by a powerful El Niño episode, a natural oceanic phenomenon that leads to a rise in temperatures.

It is also 93% likely that the average temperature for the period 2022-2026 will be higher than that of the last five years (2017-2021).

Dr Leon Hermanson of the Met Office edited the newsletter. He believes that these forecasts show “that the rise in global temperature will continue”.

But, he noted, “a single year of exceeding the 1.5°C threshold does not mean that we will have crossed the emblematic threshold of the Paris Agreement; however, it is a sign that we are getting closer to a scenario where the 1.5°C threshold could be exceeded for an extended period”.

In 2021, the planet’s average temperature rose 1.11°C above that of the pre-industrial benchmark, according to a recent WMO report on the state of the global climate. The final version of the document will be published on May 18.

Back-to-back La Niña episodes in early and late 2021 caused global temperatures to cool, “but this is only temporary and does not reverse the long-term global warming trend,” the WMO said. The appearance of an El Niño episode would immediately contribute to the increase in temperatures.

See also on The HuffPost: The 3 attitudes really useful for the climate according to the IPCC

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