Scientists have studied Arctic ice and its dynamics extensively. Less those of Antarctica. But today, thanks to a major reconstruction work, researchers are presenting data that date back to the beginning of the 20th century.and century. They show new patterns, signs according to them, that “something dramatic is happening”.
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[EN VIDÉO] Antarctic ice cover is growing The Antarctic ice cover has never been greater than in 2012, the proof in pictures.
L’Antarctic remains a difficult continent to study. Until then, scientists lacked, for example, an image detailing the extent of sea ice in the region over the entire 20thand century. But Ohio University researchers (United States) have just published data which finally makes it possible to know more about the evolution of the antarctic ice floe. What confirms that the phenomenon of increase in its extent observed by satellite since the beginning of the 1980s is unique.
The researchers did a lot of reconstruction work. On the one hand, data recorded over time by a small number of meteorological stations, reports of human observations and samples of ice cores and sediment oceanic. And on the other hand, historical meteorological data in places further away from Antarctica. Because there is a close link between the extent of sea ice and regional or larger-scale climate variability. Result: information no longer available on a specific region of Antarctica or at a particular time of the year, but on the whole continent and over the four seasons.
The precision work of researchers at the University of Ohio shows, on the Antarctic side, since 1979, a tendency towards a slow overall increase in the surface of sea ice, even though it was rather on the decline since the beginning of the XXand century. Then one anomaly in 2016 and 2017 with suddenly decreasing sea ice extent. To finally rebound in mid-2020 and find itself again below average at the start of 2022.
Mechanisms that remain to be understood
Researchers believe that these variations in the extent of Antarctic sea ice mark changes in our climate system. Unprecedented changes at least over the last 150 years or so. And even if they do not explain, for the moment, the sudden withdrawal observed in 2016, they believe that it is a sign that “something quite dramatic is afoot”.
The latest data collected should, however, provide a better understanding of the changes taking place on the pack ice. Significant changes because if the melting sea ice does not affect the sea level, it can have consequences for ecosystems and biodiversity.
Remember that the penguins and seals that live there are a bit like the polar bears of the arctic. They are critically dependent on the amount of sea ice present. In addition, ocean circulation, including the formation of dense water that can sink to the bottom of the ocean, is also linked to changes in sea ice. And “changes in the ocean around Antarctica may have global implications”, warns Ryan Fogt, a geographer at the University of Ohio, in a communicated.
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