The summer of 2023 is gradually taking shape as extraordinary in the human annals, with the confirmation Thursday by the European observatory Copernicus that the combined effect of climate change and the return of the phenomenon El Nino push the temperatures on oceans and on land to levels never seen before.
Even if it is uncertain to predict the rest of the summer, the temperature records have been linked since April on the globe, from China to Spain via the Atlantic Ocean, the most direct sign of the disruption of the climate. climate of the planet, with the disasters it stirs up in a less predictable way: forest fires, droughts, extreme rains, etc.
“June was the hottest month globally, just over 0.5°C above the 1991-2020 average, far exceeding the previous record of June 2019,” the observatory said. climate change Copernicus (C3S) of the European Union, whose data, which go back to 1950, are among the most reliable and used in the world with those of the American NOAA.
Temperatures broke records in northwestern Europe while parts of Canada, the United States, Mexico, Asia and eastern Australia “were significantly warmer than normal”, notes Copernicus, who insists on the extent of the deviation from normal.
By contrast, it was cooler than normal in western Australia, western United States and western Russia.
For 15 years, the month of June has been constantly above the averages of the period 1991-2020, but “June 2023 is very much above the others, it is the kind of anomaly that we are not used to” , explained to AFP Julien Nicolas, scientist of the C3S.
In the end, the average global temperature was 16.51°C in June, or 0.53°C above the average of the previous three decades. The previous record, in June 2019, was just 0.37°C above these normals.
Marine heatwaves
“The June 2023 record is largely due to very high ocean surface temperatures,” which make up 70% of the earth’s surface, he said.
Temperatures had already reached record levels in May in the Pacific Ocean as a result of the start of the climatic phenomenon El Nino. In June, in turn, the North Atlantic experienced sea heat waves “which surprised many people by reaching truly unprecedented levels”, according to the C3S expert.
“One of the factors is the weaker wind speeds in large areas of the North Atlantic”, due to an Azores anticyclone measured as “the weakest for a month of June since 1940”, which reduced the mixing of surface waters and thus their cooling.
“On top of that, there is the warming trend of the oceans which absorb 90% of the heat produced by human activity,” Nicolas added, as humanity’s greenhouse gas emissions continue to increase.
“Extreme marine heat waves” were measured in the Baltic Sea as well as around Ireland and Great Britain, which already confirmed its record month of June a few days ago, again very clearly above from the previous one.
And the trend continues in July: Tuesday was the hottest day ever measured globally, all months combined, according to preliminary US data.
Warming will be fueled in the coming months by El Ninowhich will continue all year round at an “at least moderate” intensity, according to the World Meteorological Organization (WMO, a specialized agency of the UN).
At the same time, “the Antarctic sea ice reached its lowest extent for the month of June since the start of satellite observations, 17% less than average”, according to Copernicus, again by a margin significant. In February, its surface had reached, at the end of the austral summer, its historic minimum for the second consecutive year.