Over the next five years, there is a one in two chance that the planet will experience a fever rise 1.5°C higher than pre-industrial values. And for at least a year. This is the main news contained in the new bulletin on the climate published this Tuesday by the World Meteorological Organization (WMO) of the United Nations. The organization notes that the probability of a temporary overshoot of the 1.5°C threshold has steadily increased since 2015, when this risk was close to zero. For the years between 2017 and 2021, the probability of exceedance was 10%. She has passed “nearly 50% for the period 2022-2026”, says the WMO. But there is only a small probability (10%) that the five-year average exceeds the threshold of +1.5°C.
A temporary crossing of this threshold over a year is not, however, synonymous with a lasting overrun of this threshold, as understood by the Paris Climate Agreement, which aims to contain the increase in the average temperature. world well below 2 degrees Celsius compared to pre-industrial levels and if possible 1.5 degrees. Nevertheless, the signal is alarming. “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 the climate will be increasingly harmful for populations and for the entire planet.explains 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 conditions will continue to intensify.”warns the Finn, who points out that the warming of the Arctic is “particularly marked”even as the conditions prevailing in this region have repercussions on the entire planet.
Hottest new year on record ‘very likely’ by 2026
According to this bulletin on annual to decadal forecasts of the climate on a global scale, produced by the Met Office of the United Kingdom (Met Office), which is WMO’s main center for this type of forecast, it is also 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, who edited the bulletin, believes that these forecasts show “that the rise in global temperature will continue”. And he also notes that if “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, it is however a sign that we are approaching a scenario where the threshold 1.5°C could be exceeded for an extended period”.
In 2021, the planet’s average temperature will be 1.11°C above the benchmark pre-industrial era, 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 have resulted in cooling global temperatures, according to the WMO. “but this is only temporary and does not reverse the trend of global warming in the long term”. The appearance of an El Niño episode would immediately contribute to the increase in temperatures.