A new study has shown that the Gulf Stream system could collapse as soon as 2025.
The shutting down of the vital ocean currents, which is referred to as the Atlantic Meridional Overturning Circulation (Amoc) by scientists, would bring catastrophic climate impacts.
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 that at least, 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.
Amoc was already known to be at its weakest in 1,600 years owing to global heating and researchers spotted warning signs of a tipping point in 2021.
The new analysis estimates a timescale for the collapse of between 2025 and 2095, with a central estimate of 2050, if global carbon emissions are not reduced. Evidence from past collapses indicates changes of temperature of 10C in a few decades, although these occurred during ice ages.
Other scientists said that 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. But all said the prospect of an Amoc collapse was extremely concerning and should spur rapid cuts in carbon emissions.
Amoc also carries warm ocean water northwards towards the pole where it cools and sinks, driving the Atlantic’s currents. However, an influx of fresh water from the accelerating melting of Greenland’s ice cap and other sources is increasingly smothering the currents.
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A collapse of Amoc is expected to 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. It would increase storms and drop temperatures in Europe, and lead to a rising sea level on the eastern coast of North America. It would also further endanger the Amazon rainforest and Antarctic ice sheets.
“I think we should be very worried,” said Prof Peter Ditlevsen, at the University of Copenhagen in Denmark, and who led the new study. “This would be a very, very large change. The Amoc has not been shut off for 12,000 years.”
The Amoc reportedly collapsed and restarted repeatedly in the cycle of ice ages that occurred from 115,000 to 12,000 years ago. It is one of the climate tipping points scientists are most concerned about as global temperatures continue to rise.
Story was adapted from the Guardian.
