Global temperature will break all records in 2023. And even in the context of global warming, scientists have had difficulty explaining it. Today, they point the finger at a culprit: that blue sky we love so much!
In 2023, global temperatures will reach abnormal levels. According to data from the European Copernicus Climate Change Service (C3S), the average temperature on our planet during this year was 14.98 °C. This is 1.48°C warmer than pre-industrial levels. And researchers have so far struggled to explain it. Even taking into account the accumulation of greenhouse gases in our environment and trends the childthe childIn particular, there is still a gap that scientists do not understand.
However, there are other phenomena that can affect temperature. Increased solar activity, large amounts of water vaporthe windthe wind From volcanic eruptions or reduction of aerosol particles in the atmosphere. Scientists included them in their calculations. Even so, the 0.2°C warming remained impossible to explain. And there have been discussions on this topic. angeranger Within the scientific community
Albedo to explain the 2023 temperature record
Today finally, PhysicistPhysicist Climate of the institute Alfred WagnerAlfred Wagner (Germany) Provide an answer. After an in-depth analysis of satellite data NASANASAas well as data from the European Center for Medium-Range Weather Forecasts (ECMWF) – on which the Copernicus service relies – which includes observations and ModelingModeling In complex newspaper Sciencehe explains that 2023 stood out as the year.albedoalbedo Lowest planet possibly lowest since 1940. Without it, the models give an average temperature for 2023 that is corrected by about 0.23 °C.
This deserves some explanation. Regarding the term albedo, first. Defines the part of Solar radiationSolar radiation which is reflected back into space instead of being absorbed by the system. TereTere. and therefore contributes less to global warming. Since the 1970s, scientists have noted a decrease in this albedo. Especially due to the melting of sea iceArcticArctic. The white, reflective surfaces of the snow are replaced by deep ocean surfaces. Since 2016, the situation has worsened as it started. SourceSource Ice in the seaAntarcticAntarctic.
The role of clouds in warming our atmosphere
However, what the Alfred Wagner Institute researchers found is that the decrease in surface albedo in the polar regions ultimately accounts for only 15 percent of the recent decrease in planetary albedo. According to them, we should look a little higher to account for the impact recorded in 2023. LatitudeLatitude Our Northern Hemisphere average and TropicalTropical.
“It is striking that the northeast Atlantic, one of the main drivers of the most recent increase in global average temperature, has seen a substantial decrease in low-level clouds not only in 2023, but for almost the entire Like The Atlantic – Over the Last Ten Years »stress researchers. At this point, the data is clear. There are fewer and fewer. the cloudthe cloud Low altitude and almost always medium and high altitude clouds.
Towards an increase in global warming?
And the news isn’t good either. Because certainly high altitude clouds also reflect radiation. SoleilSoleil. But above all they maintain naturally. The heatThe heat emanates from the earth’s surface. A bit like Green house gasGreen house gas. “If there are fewer clouds, we just lose the cooling effect, which warms the climate.”note the researchers.
The next question is, why have there been fewer clouds in recent years? Perhaps, in part, an unintended – and unexpected – effect of improving our air quality. With stricter regulations appearing on marine fuels, in particular, the number of aerosols in our atmosphere has decreased. However, aerosols are known to participate in the formation of clouds. Natural fluctuations or even FeedbackFeedback Oceanic conditions may also play a role in the gradual disappearance of cloud cover at low altitudes.
But climate physicists at the Alfred Wagner Institute point to a much more troubling culprit: global warming itself. “If a large part of the albedo reduction is indeed due to feedback between Global WarmingGlobal Warming And with fewer clouds, as some models suggest, we should expect much warmer temperatures in the future.they warn.We may see long-term global warming of more than 1.5°C earlier than previously predicted. Budget CarbonCarbon The rest, tied to the limits set out in the Paris Agreement, should be reduced accordingly. And the need to implement adaptation measures for the impacts of future extreme weather events will become even more urgent. »
