![]() ![]() He said the tipping point could lead to a partial Amoc collapse, for example only in the Labrador Sea, but that this would still cause major impacts. The extrapolation in the new analysis was reasonable, according to Prof Tim Lenton, at the University of Exeter, UK. Prof David Thornalley, at University College London, UK, agreed the study had large caveats and unknowns and said further research was essential: “But if the statistics are robust and a relevant way to describe how the actual Amoc behaves, then this is a very concerning result.”ĭr Levke Caesar, at the University of Bremen, Germany, said using sea surface temperatures as proxy data for the strength of the Amoc currents was a key source of uncertainty: “We only have direct observational data of the Amoc since 2004.” “The results of the new study sound alarming but if the uncertainties in the heavily oversimplified model and in the underlying data are included, then it becomes clear that these uncertainties are too large to make any reliable estimate of the time of tipping.” Prof Niklas Boers, from the Potsdam Institute for Climate Impact Research in Germany, revealed the early warning signs of Amoc collapse in 2021. The Atlantic Meridional Overturning Circulation is weakening and has collapsed in the distant past The potential collapse of Amoc is intensely debated by scientists, who have previously said it must be avoided “at all costs”. But Ditlevsen said the models used have coarse resolution and are not adept at analysing the non-linear processes involved, which may make them overly conservative. ![]() The most recent assessment by the Intergovernmental Panel on Climate Change concluded that Amoc would not collapse this century. 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. The analysis is based on greenhouse gas emissions rising as they have done to date. Further statistical analysis provided a measure of the uncertainty in the estimate. The researchers were then able to extrapolate the data to estimate when the tipping point was likely to occur. The data fitted “surprisingly well”, Ditlevsen said. The researchers then mapped this data on to the path seen in systems that are approaching a particular type of tipping point called a “saddle-node bifurcation”. The new study, published in the journal Nature Communications, used sea surface temperature data stretching back to 1870 as a proxy for the change in strength of Amoc currents over time. Research in 2022 showed five dangerous tipping points may already have been passed due to the 1.1C of global heating to date, including the shutdown of Amoc, the collapse of Greenland’s ice cap and an abrupt melting of carbon-rich permafrost. It is one of the climate tipping points scientists are most concerned about as global temperatures continue to rise. The Amoc collapsed and restarted repeatedly in the cycle of ice ages that occurred from 115,000 to 12,000 years ago. The Amoc has not been shut off for 12,000 years.” “This would be a very, very large change. “I think we should be very worried,” said Prof Peter Ditlevsen, at the University of Copenhagen in Denmark, and who led the new study. It would also further endanger the Amazon rainforest and Antarctic ice sheets. It would increase storms and drop temperatures in Europe, and lead to a rising sea level on the eastern coast of North America. But an influx of fresh water from the accelerating melting of Greenland’s ice cap and other sources is increasingly smothering the currents.Ī collapse of Amoc would have disastrous consequences around the world, severely disrupting the rains that billions of people depend on for food in India, South America and west Africa. But all said the prospect of an Amoc collapse was extremely concerning and should spur rapid cuts in carbon emissions.Īmoc carries warm ocean water northwards towards the pole where it cools and sinks, driving the Atlantic’s currents. Other scientists said the assumptions about how 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. Evidence from past collapses indicates changes of temperature of 10C in a few decades, although these occurred during ice ages. The new analysis estimates a timescale for the collapse of between 20, with a central estimate of 2050, if global carbon emissions are not reduced. ![]()
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