“Scientists have warned of these disappearances for decades, and it is sad to see that those warnings have largely gone unheeded.” It’s too late now. » The observation was signed by Dirk Notz of the University of Hamburg, co-author of a study on Arctic sea ice published Tuesday, June 6, 2023.
Scientists from Korea, Canada and Germany used observational data from 1979 to 2019 to run new simulations. “The results indicate that the first month of September without sea ice will occur as early as 2030 to 2050, regardless of greenhouse gas emission scenarios,” They close in the journal Nature Communications.
Scientists are in no doubt that 90% of this decline is due to human activities and greenhouse gas emissions, while the other factors (aerosols, solar and volcanic activity, etc.) are far less important.
Faster than expected…
What are we talking about when we talk about summer sea ice? The Arctic Ocean covers an area of about 14 million km2 and is covered with ice most of the year. The absence of summer ice means an area of less than 1 million km2, as there can always be residual ice along the coasts. And September is the month when the ice usually reaches its annual minimum.
This study also shows that the first ice-free summer could be in the 2030s if greenhouse gas emissions slowly decrease or continue to increase. “That’s about a decade earlier than the latest IPCC forecasts” the group of climate experts commissioned by the United Nations, points out Seung-Ki Min of South Korea’s Pohang and Yonsei Universities, co-author of the article.
Adverse Consequences
Sea ice, the pack ice, is salt water on the surface of an ocean that has frozen under the action of the cold. In Le Figaro, the CNRS oceanographer and climatologist Jean-Baptiste Sallée remembers it “The pack ice reflects the sun’s rays. Its disappearance will increase global warming and risk a vicious circle. »
With its disappearance, summer ice is accelerating the warming of the Arctic. “which can amplify mid-latitude extreme weather events such as heat waves, wildfires and floods”, adds Seung-Ki Min. And if its melting doesn’t directly lead to sea level rise, it is contributing to it by melting the Greenland ice cap. Not to mention the impact on permafrost, which releases CO2 as it melts.
A turning point
The disappearance of summer ice in the Arctic is one of the ecological turning points, a sign of irreversible changes, as well as the partial (Antarctic) or total (Greenland) melting of the ice caps, the transformation of the Amazon forest into the savannah, the thawing of the permafrost … “This will be the first major component of our climate system that we lose through our greenhouse gas emissions.” emphasizes Dirk Notz.
Rather than inspire a desire to give up and sink into fatalism, scientists hope this study will serve as a wake-up call. One would like to say something else… But Dirk Notz now hopes that politicians will pay attention to the findings of the researchers “So that we can at least protect the other components of our climate system by limiting future warming as much as possible.”