Climate scientists have detected warning signs of the collapse of the Gulf Stream, one of the planet’s main potential tipping points although estimates of the critical transition point remain uncertain.

The research from the Potsdam Institute for Climate Impact Research in Germany found “an almost complete loss of stability over the last century” of the Atlantic meridional overturning circulation (AMOC). The currents are already at their slowest point in at least 1,600 years, but the new analysis shows they may be nearing a shutdown.

“The signs of destabilisation being visible already is something that I wouldn’t have expected and that I find scary,” said Niklas Boers, from the Potsdam Institute for Climate Impact Research in Germany, who did the research.

Eight independently measured datasets of temperature and salinity going back as far as 150 years enabled Boers to show that global heating is indeed increasing the instability of the currents, not just changing their flow pattern. The analysis concluded: “This decline [of the AMOC in recent decades] may be associated with an almost complete loss of stability over the course of the last century, and the AMOC could be close to a critical transition to its weak circulation mode.” Click here

Levke Caesar, at Maynooth University in Ireland, who was not involved in the research, said: “The study method cannot give us an exact timing of a possible collapse, but the analysis presents evidence that the AMOC has already lost stability, which I take as a warning that we might be closer to an AMOC tipping than we think.”

David Thornalley, at University College London in the UK, whose work showed the AMOC is at its weakest point in 1,600 years, said: “These signs of decreasing stability are concerning. But we still don’t know if a collapse will occur, or how close we might be to it.”

Click here for the paper