A small change in temperature between the “ocean skin” and the water below was found to make more CO2 be absorbed.
A British-led group of scientists has found that a thin layer of cool water less than 2 mm deep helps oceans take in carbon dioxide. They came to this conclusion after months of carefully tracking levels of gas and temperature across the Atlantic.
The experts saw that the slight temperature difference between the “ocean skin” and the layer of water below it makes an opening that lets more CO2 in.
They used very sensitive tools to find out how warm the water was and to see and record very small changes in the amount of CO2 in the air moving toward and away from the ocean surface.
People think this work is important for improving climate models since the seas take in about a quarter of the carbon that people put into the air.
According to Daniel Ford, a research fellow at the University of Exeter, “This work not only shows how important the oceans are, but it should also help us improve the global carbon assessments that are used to guide emission reductions.” The Cop29 climate change meeting is happening next month.
On the way from Southampton to Punta Arenas in Chile, Ford was on the research ship RRS Discovery. He said, “During the seven weeks of the cruise, all the different instruments had to keep working together to get the wide range of measurements that were used in the study.”
“The seas were rough in the North Atlantic and near the Falklands, which was tough. But the ocean near the equator was calm and glassy, which was nice.”
The 2mm piece of water is a little cooler because of the “cool skin effect.” This happens when heat leaves the water because it is touching the air.
The findings, which were published in the journal Nature Geoscience, have been sent to the Global Carbon Budget assessment, which is a group of scientists from around the world working together to get a better idea of how carbon moves around on Earth.
Ocean and weather scientist at the University of Exeter Prof. Jamie Shutler said that the “ocean skin” was just a bit cooler than the water below it. The difference in gas concentrations between these layers controls how much CO2 is taken in.
Shutler said that people first thought about the effects in the early 1990s. “The field evidence, however, was the most important piece we were missing,” he said.
Gavin Tilstone from Plymouth Marine Laboratory said, “This discovery shows how complicated the structure of the ocean’s water column is and how it can affect the removal of CO2.” As we keep improving our climate models and predictions, it’s important to understand these subtle processes. It shows how important the ocean is for keeping the temperature and carbon cycle in check.
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