Schematic diagram of the experiment. Credit: Qiyun Ma and Patrick Scholz
Using climate models, a team of German and Chinese climate scientists has found evidence that freshwater input into the Irminger Basin will have the greatest impact on the Atlantic Meridional Circulation (AMOC) in the coming years. Their paper is published in the journal Science Advances.
The AMOC is the major ocean current in the Atlantic Ocean. It consists of a northward flow of warm, salty water in the upper Atlantic Ocean and a southward flow of cooler, denser, deeper water, including the Gulf Stream. Previous studies have shown that it plays an important role in the Earth’s climate system, particularly in Europe’s climate.
Research also shows that climate change is impacting the AMOC and can lead to unpredictable changes in weather patterns. These effects are thought to be due to changes in freshwater input to the AMOC due to changes in rainfall or snowmelt. Fresh water reduces surface water density, prevents water from sinking to the lower layers, and reduces return flow to the south.
In this new study, the research team wondered which freshwater input sources have the greatest impact on AMOC. To find out, they added features of the region to the Alfred Wegener Institute’s climate model and looked at each of the major sources of freshwater flowing into the AMOC.
They found that freshwater input into the Irminger Basin from Greenland snowmelt has the largest impact of all known freshwater inputs. They point out that this is due to its unique location in the Irminger Basin. It is located at the point where AMOC changes course from north to south and makes a U-turn. Therefore, the cold fresh water that pours directly into the ocean currents stays close to the surface, slowing the ocean currents.
Such a slowdown is not overcome when the AMOC reorients itself in the tropics, thus slowing the northward movement of warm water. As a result, the overall AMOC will slow down and its power will weaken, but the impact is still unclear.
Further information: Qiyun Ma et al., Reconsidering the climate impacts of the AMOC slowdown: dependence on freshwater location in the North Atlantic, Science Advances (2024). DOI: 10.1126/sciadv.adr3243
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Citation: Greenland meltwater will slow Atlantic circulation, climate models suggest (November 21, 2024) https://phys.org/news/2024-11-greenland-meltwater-atlantic-circulation-climate Retrieved November 21, 2024 from .html
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