The Gulf Stream, a system of ocean currents that plays a crucial role in the climate, may reach an irreversible point of collapse much sooner than previously thought. Previously, scientists thought the point of no return for the Gulf Stream would happen after 2100. Now, a group of Dutch climate scientists has concluded that the tipping point may happen around 2060, NOS reports.
“What this study makes concrete is that we have a year for the start of the Gulf Stream collapse, around 2060,” researcher René van Westen of Utrecht University told the broadcaster. “That is alarmingly closer than previously thought, possibly even within our lifetime.”
The Gulf Stream, also known as the Atlantic Meridional Overturning Circulation (AMOC), transports heat around the Earth like a conveyor belt. Global warming is slowing the Gulf Stream down, and scientists fear that it will eventually lead to an irreversible process where the important current collapses completely. If that happens, temperatures in northwest Europe would drop, resulting in colder winters, less rainfall, and more severe storms. In the Southern Hemisphere, it will get even hotter.
The UN climate panel, IPCC, previously forecast that the tipping point would be reached at global warming above 4 degrees Celsius. But based on the latest climate models and the help of supercomputers, Van Westen and his colleagues now expect that to occur as early as 2.5 degrees Celsius. The Earth has warmed by 1.3 degrees so far. Once the tipping point is past, it will take about 100 years for the Gulf Stream to slow to a complete stop.
With moderate CO2 emissions, the Dutch researchers expect that the tipping point will be reached at around 2063. With high emissions, the collapse could begin as early as 2055.
The Gulf Stream’s slowing is already starting to affect the weather, and northwestern Europe will start noticing the cooling effect in the coming decades, Van Westen said. “On the one hand, you have global warming, but on the other hand, the cooling effect of the weakening AMOC. From now on, we can expect a slight trend of cooling in the coming years.”
According to Van Westen, it is not too late to stop the collapse. “Our study also shows that if you limit warming, the risk of the Gulf Stream collapsing becomes increasingly smaller. And you can even prevent it entirely, but then action must be taken.”
That action is crucial because the collapse of the Gulf Stream will be devastating, two climate scientists not involved in this study told NOS. “If that happens, it will become colder, harsher, and drier here. We’ll have additional sea level rise, more storm surges, and agricultural yields will decrease by about a third. And all of that will last for centuries,” Sybren Drijfhout, professor of climate at the University of Southampton and Utrecht University, said.
“People sometimes jokingly say, ‘Then we could ice skate more often.’ But we won’t have time for that, because the entire food supply will collapse,” said Caroline Katsman, professor of oceans and climate at TU Delft.
https://www.nature.com/articles/s41561-021-00699-z
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