Giving Compass' Take:
- Researchers point out that intense global warming will lessen the ocean's ability to soak up carbon emissions in the future.
- How can this research help shed light on the direction of ocean conservation and climate-based efforts?
- Read more about oceans and climate change.
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The oceans soak up carbon dioxide emissions, helping to limit global warming—but intense warming in the future could lessen that ability, leading to even more intense warming, scientists warn.
For a new study, the researchers analyzed a climate simulation configured to a worst-case emissions scenario and found that the oceans’ ability to soak up carbon dioxide would peak by 2100, becoming only half as efficient at absorbing the greenhouse gas by 2300.
The decline happens because of the emergence of a surface layer of low-alkalinity water that hinders the ability of the oceans to absorb CO2. Alkalinity is a chemical property that affects how much CO2 can dissolve in seawater.
Although the emissions scenario used in the study is unlikely because of global efforts to limit greenhouse gas emissions, the findings reveal a previously unknown tipping point that if activated would release an important brake on global warming, the authors say.
“We need to think about these worst-case scenarios to understand how our CO2 emissions might affect the oceans not just this century, but next century and the following century,” says Megumi Chikamoto, who led the research as a research fellow at the University of Texas Institute for Geophysics.
Today, the oceans soak up about a third of the CO2 emissions generated by humans. Climate simulations had previously shown that the oceans slow their absorption of CO2 over time, but none had considered alkalinity as explanation. To reach their conclusion, the researchers recalculated pieces of a 450-year simulation until they hit on alkalinity as a key cause of the slowing.
According to the findings, the effect begins with extreme climate change, which supercharges rainfall and slows ocean currents. This leaves the surface of the oceans covered in a warm layer of fresh water that won’t mix easily with the cooler, more alkaline waters below it. As this surface layer becomes more saturated with CO2, its alkalinity falls and with it, its ability to absorb CO2. The end result is a surface layer that acts like a barrier for CO2 absorption.
That means less of the greenhouse gas goes into the ocean and more of it is left behind in the atmosphere. This in turn produces faster warming, which sustains and strengthens the low-alkalinity surface layer.
Read the full article about oceans' ability to soak up emissions by Anton Caputo at Futurity.