“It has basically been predicted for decades that this circulation would weaken due to global warming. And now we have the strongest evidence that this is already happening,” said Stefan Rahmstorf of the University of Potsdam, who contributed to this research.
The Atlantic Meridional Overturning Circulation (AMOC) transports water across the planet’s oceans, including the Atlantic Ocean, the Pacific Ocean, and India. The region contributing to the slowdown, according to research, is the North Atlantic Ocean.
“The idea (of this movie), which is actually correct, is that if this Atlantic reversal circulation breaks everything together, it will lead to a strong cooling around the northern Atlantic Ocean, especially in Europe, in the kind of coastal areas (of) “Britain and Scandinavia. But it is only true if the collapse breaks everything together,” Rahmstorf said.
“This indicates that the slowdown is probably not a natural change, but the result of human influence. The AMOC has a profound impact on the world climate, and especially in North America and Europe, and therefore this evidence of ‘ a continuing weakening of the circulation of critical evidence. evidence for the interpretation of future projections of regional and global climate, “said Andrew Meijers, deputy scientific leader of polar oceans at British Antarctic Survey.
‘Both surface warming and the increased water cycle, increased rainfall and ice melt are a result of global warming’ in parts of the North Atlantic.
As hot water currents move northward, they usually turn southward as they become cooler and heavier. Addition of fresh water from the melting ice causes the rotation to slow down due to reduced salt content.
US east coast to see higher sea levels
One of the major consequences of the slow circulation in the sea is at sea level, especially that of the American east coast.
“The northward flow of the AMOC leads to a deflection of bodies of water to the right, away from the U.S. east coast. This is due to the rotation of the earth that moves moving objects such as currents to the right in the Northern Hemisphere and to the left in the “Southern Hemisphere. As the current slows down, this effect weakens and could accumulate more water off the U.S. east coast, leading to an improved sea level rise,” said Levke Caesar, one of the report’s authors.
The rate at which these waters are rising has also increased over the past few years.
“The rate of global sea level rise has more than doubled from 1.4 mm per year for most of the twentieth century to 3.6 mm per year from 2006-2015,” NOAA said.
A further slowdown in global ocean circulation, especially along the major Gulf Stream on the U.S. east coast, could combine with the ever-increasing sea level rise to make the major northeastern cities even more vulnerable to flooding.
Hot heat waves, stronger hurricanes
“The seven warmest years in the world have all occurred since 2014, with ten of the warmest years since 2005,” NOAA said. Heat waves are becoming more frequent.
The ocean and currents also play a role in the uptake of carbon dioxide, the most dominant greenhouse gas, from the atmosphere. The changing currents could reduce the amount of carbon taken out of the atmosphere, according to NASA.
Marine organisms “depend very strongly on these ocean currents, which basically set the conditions for the entire ecosystem in terms of nutrient supply, temperature and salinity,” Rahmstorf said.
Asked whether the AMOC could slow down further or even stop, Rahmstorf said climate models suggest that currents will slow down to between 34% and 45% by 2100.
“Despite a lot of research over the last decade on this, it’s very difficult to quantitatively determine how far it is bouncing. But the kind of simulations I know suggest that if you weaken this circulation by about half, we get into “A critical condition. And so it could very well happen at the end of the century,” Rahmstorf said.
“We have to (strive to) stay away from that tipping point, because the consequences if the circulation were to break everything down would be dramatic.”