Scientists are sounding the alarm over the faster-than-anticipated collapse of a complex system of ocean currents in the Atlantic, likely to have “catastrophic” consequences for the Nordic countries plunged into the cold while the rest of the planet is warming.
In an open letter to the leaders of the Nordic Council who meet on Monday in Reykjavik, around forty international researchers emphasize that the effects would “probably” be felt all over the world.
The “Atlantic Meridional Overturning Circulation” (AMOC) is a complex system of ocean currents, including the Gulf Stream, which regulate heat between the tropics and the Northern Hemisphere and are therefore decisive for living conditions in the Arctic.
The collapse of this system, already weakened over the past two decades, is one of the tipping points that worries scientists because of the cascade of disasters it could trigger.
But there is no consensus on when it should occur.
In their 6e assessment report published in 2023, the climate experts mandated by the UN (IPCC) express “a medium level of confidence in the fact that the Atlantic meridional overturning circulation will not collapse before 2100”.
However, say the signatories of the open letter, recent work “suggests that the IPCC has underestimated this risk and that crossing this tipping point is a serious possibility in the coming decades”.
“The impacts, particularly on the Nordic countries, would likely be catastrophic, including major cooling of the region while surrounding regions warm,” they note.
“This would represent an amplification and intensification of the “cold blob” [zone anormalement froide] which has already formed over the subpolar Atlantic, and would likely lead to unprecedented extreme weather events,” they add.
This could “potentially” threaten the viability of agriculture in northwest Europe, they argue.
But its effects would also “probably” be felt on a global scale with “a shift in tropical precipitation belts, less oceanic absorption of carbon dioxide [et donc une augmentation plus rapide dans l’atmosphère] as well as a significant rise in sea level.
The Nordic Council brings together Denmark, Finland, Iceland, Norway and Sweden as well as several territories in the region (The Faroe Islands, Greenland, Åland).
Their leaders are meeting Monday and Tuesday in Reykjavik for a summit to which Ukrainian President Volodymyr Zelensky has also been invited.
