Weak circulation of the highly volatile Atlantic Ocean

Historical records refer to sea surface temperatures

Meanwhile, experts have found various solutions to the methodological problem. For example, by analyzing sediment samples from the sea floor, whose chemical composition provides clues to conditions in the oceans hundreds of years ago. For the new study, researchers working with Spectrum used historical records documenting surface temperatures across the Atlantic going back as far as 1900. Because changes in the AMOC can affect water temperatures differently, the state of the stream can be assessed with the help of the recordings. In addition, Latif and colleagues combined their historical analyzes with climate model simulations to determine the causes of AMOC’s weakness.

The result is that man-made global warming is actually affecting the flow regime. It’s a “kind of footprint” of climate change, Latif puts it. Natural variance still dominates what’s happening right now. However, the impact of climate change is growing in the background. “As greenhouse gases continue to build up in the atmosphere, all models predict a sharp slowdown in the circulation,” Latif explains. The question is when this signal becomes the dominant force affecting the flow. If not now, then surely sometime in the future the planet must continue to warm.

The study’s findings are fully consistent with other recent research on AMOC slowdowns, Stefan Ramstorf, an oceanographer at the Potsdam Institute for Climate Impact Research, wrote in an email to E&E News. Rahmstorf was not involved in the new study, but he has published several important research papers on AMOC attenuation over the past few years.

In his opinion, there is ample evidence of at least some influence of man-made global warming. These include the “footprint” of climate change that the new study refers to, then the fact that climate models predict a slowdown due to greenhouse gas emissions, and the trend in which the recent slowdown appears to be the most extreme in the past millennium. .