three things to remember from Copernicus’ results for the year 2023, the hottest year ever recorded in the world

In a previous report published on December 6, Copernicus already assured that 2023 would be the hottest year on record. December data only confirmed the trend : the last month of the year was December the hottest on record globally, with an average temperature of 13.51°C, 1.78°C above the 1850-1900 level for the month. Here are the main lessons from this report.

The world on the verge of the +1.5°C limit of the Paris agreement

Signed in 2015 at the end of COP21, the Paris Agreement threshold aims to maintain “the increase in global average temperature to well below 2°C above pre-industrial levels” and to continue the efforts “to limit the increase in temperature to 1.5°C above pre-industrial levels”. However, itCompared to the pre-industrial era, the global average temperature of 2023 represents an increase of 1.48°C.

From the beginning of June, the symbolic threshold of 1.5°C was exceeded for several days, underlines Copernicus which points out “one of the first signs testifying to the exceptional nature of this year 2023”. “Even if this was not the first time that this daily anomaly threshold was exceeded, this had never happened so early in the year”continues the institute, adding that“he is likely that a period of 12 months ending in January or February 2024 will exceed the pre-industrial level by 1.5°C. VShowever “this does not mean that the limit set by the Paris agreement has been exceeded”, continues Copernicus.

During another extraordinary review of this year, during the COP28 organized in Dubai in December, Chris Hewitt, director of the climate branch of the World Meteorological Organization (WMO) already insisted on this point : the threshold of 1.5°C established in the Paris agreement refers to “warming over decades, over a period of at least twenty years” and not, as during the last year, “isolated days or weeks.” “Even if we cross the threshold of +1.5°C, this would, for the moment, only concern a single year. This is not enough to say that the limit described in the Paris agreement has been crossed. concluded the scientist.

According to Copernicus, global daily temperature anomalies above 1.5°C “have become regular, to the point that almost 50% of the days in the year 2023 exceeded the level of 1850-1900 by 1.5°C.” Likewise, thehe year 2023 is also the first year in which every day exceeded the levels of 1850-1900 by one degree. Finally, two days in November were, for the first time, 2°C warmer.

Record temperatures in the oceans

Ocean surface temperatures also showed levels “unprecedented”. They “were a driving factor in the unusual atmospheric temperatures observed throughout 2023”, continues Copernicus. For the period included between April and December, these temperatures were the highest for this time of year in the ERA5 data set, the tool used by the Observatory and which allows us to go back to 1940. While he cites the role of the El Niño Southern Oscillation (ENSO) in this warming of the oceans, “the transition to El Niño alone does not explain the entire increase in global ocean surface temperatures in 2023”insists Copernicus. “Because the [températures de surface] high outside the equatorial Pacific [où le courant El Niño se manifeste] contributed significantly to the establishment of records (…) on a global scale.”

At the North Pole as well as the South Pole, the melting of the ice has also reached worrying levels in 2023. But it is in the South that the effects of climate on sea ice have crossed an unprecedented threshold. In Antarctica, “it reached record minimums for the corresponding period of the year, for eight months”, explains Copernicus.

“Daily and monthly ranges reached historic lows in February 2023,” according to Copernicus.