UN report | One chance in two that the +1.5°C threshold will be exceeded within 5 years

(Geneva) There is a one-in-two chance that the global average annual temperature will temporarily be 1.5C above pre-industrial levels for at least one of the next five years, the UN said on Tuesday.

Posted at 5:12 p.m

Agnes PEDRERO
Media Agency France

However, temporarily exceeding this threshold for more than a year is not equivalent to permanently exceeding this threshold within the meaning of the Paris Climate Agreement. This agreement aims to limit the rise in global average temperature to well below 2 degrees Celsius above pre-industrial levels and, if possible, to 1.5 degrees.

According to a new United Nations World Meteorological Organization (WMO) climate bulletin released on Tuesday, the likelihood of the 1.5-degree limit being exceeded temporarily has risen steadily since 2015, the year when that risk was near zero.

For the years 2017 to 2021, the probability of the limit being exceeded was 10%. It has “risen to almost 50% for the period 2022-2026,” states the WMO. However, there is only a small probability (10%) that the five-year mean exceeds the +1.5°C threshold.

“This study shows with a high level of scientific reliability that we are getting very close to the moment when we will temporarily reach the lower limit of the Paris Agreement. The 1.5°C figure is not a random statistic. It marks the point at which climate impacts will be increasingly damaging to people and the entire planet,” said WMO Secretary-General Petteri Taalas.

“As long as we 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 conditions will continue to intensify,” he warned.

He pointed out that the warming in the Arctic is “particularly pronounced” even though conditions in that region impact the planet as a whole.

hottest year?

According to this bulletin on annual to decadal global-scale climate forecasts, prepared by the United Kingdom Met Office (Met Office), the 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 will be the hottest on record.

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

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).

The Dright Leon Hermanson of the Met Office edited the Bulletin. He believes these projections show “that global temperature rises will continue.”

However, he noted: “A single year in which the 1.5 degree threshold is exceeded does not mean that we have crossed the emblematic threshold of the Paris Agreement; However, it is a sign that we are approaching a scenario where the 1.5 degree threshold could be breached for an extended period.”

According to a recent WMO report on the state of the global climate, the planet’s average temperature in 2021 will be 1.11°C above the pre-industrial era. The final version of the document will be published on May 18th.

Consecutive La Niña episodes in early and late 2021 led to a cooling in global temperatures, “but this is temporary and does not reverse the long-term global warming trend,” according to the WMO. The occurrence of an El Niño episode would immediately contribute to the increase in temperature.

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