A new study that suggests that the Gulf Stream system, the vital ocean currents called the Atlantic Meridional Overturning Circulation (Amoc), could collapse by 2025 bringing catastrophic climate impacts.
Prof Peter Ditlevsen, at the University of Copenhagen in Denmark, who led the new study says that it would be a very large change and that the Amoc has not been shut off for 12,000 years.
Other scientists are of the view that a tipping point would play out and uncertainties in the underlying data are too large for a reliable estimate of the timing of the tipping point. But they all agree that the prospect of an Amoc collapse was extremely concerning and should trigger immediate curbs on carbon emissions.
A large population depends on rain for food and livelihood in Asian and African countries and a collapse of Amoc would unleash devastating consequences on all spheres of life on earth. Apart from leading to a rise in sea level, the situation may further endanger the Amazon rainforest, monsoon in India and the ice sheets in the north pole.
The Atlantic meridional overturning circulation (AMOC) is part of a global thermohaline circulation in the oceans, which is the zonally integrated component of surface and deep currents in the Atlantic Ocean. In this, there is a northward flow of warm, salty water in the upper layers of the Atlantic, and a southward flow of colder, deep waters. Scientists are concerned about the climate tipping points as global temperatures continue to rise.
According to the study that is based on greenhouse gas emissions to date, if emissions do start to fall, as intended by current climate policies, then the world would have more time to try to keep global temperature below the Amoc tipping point.
Meanwhile, the study is also said to be exaggerating the projected catastrophe. M Rajeevan, former secretary of the Ministry of Earth Sciences (MoES), India, says, "Due to climate change there is a clear signal of AMOC weakening. But this study says it will completely collapse. I feel this could be an exaggeration. There are a lot of uncertainties in this study."
He, however, warns that the sealing could have adverse impacts over the Indian monsoon. "A recent study by IITM Pune scientists showed that Amoc weakening could impact the Indian monsoon," he says.
The climate emergency has become once again more pronounced with the findings of the new study that throw up enough caveats for governments and policymakers to pull up their socks and act.