The Guardian reports:

The Gulf Stream system could collapse as soon as 2025, a new study suggests. The shutting down of the vital ocean currents, called the Atlantic Meridional Overturning Circulation (Amoc) by scientists, would bring catastrophic climate impacts.

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 indicate changes of temperature of 10C in a few decades, although these occurred during ice ages.

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. But all said the prospect of an Amoc collapse was extremely concerning and should spur rapid cuts in carbon emissions.

Amoc carries warm ocean water northwards towards the pole where it cools and sinks, driving the Atlantic’s currents. But an influx of fresh water from the accelerating melting of Greenland’s ice cap and other sources is increasingly smothering the currents.

A 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. 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. [Continue reading…]