New research from the University of Exeter in the UK reveals that the world’s oceans soak up more carbon than previously believed. Previous estimates of the movement of carbon between the atmosphere and the oceans did not account for the temperature differences between the water’s surface and a few meters below.
The new model includes this factor and finds that there is a significantly higher flux of carbon into the oceans.
The study calculated carbon dioxide fluxes from 1992 to 2018 and found that at certain times and locations there was up to twice as much CO2 contained in the ocean as determined from previous models.
The temperature differences between the surface of the ocean and the water at a depth of a few meters is important because the amount of carbon dioxide that can be absorbed in water depends very strongly on the temperature of the water. Anyone with a home soda maker knows this well as the devices always work much better with refrigerated water than room temperature water.
The difference in ocean carbon dioxide uptake measured from satellite data and calculated in the new modeling amounts to about 10% of global fossil fuel emissions, so it is a very significant revision. The revised estimate for carbon dioxide uptake actually agrees much better with an independent method for calculating the amount of carbon dioxide in the oceans. Those measurements came from a global ocean survey performed by research ships over decades.
Now that two so-called big data estimates of the ocean sink for CO2 agree pretty well, there is greater confidence that we understand this important aspect of the planet’s carbon cycle.
Ocean carbon uptake widely underestimated
Photo, posted December 30, 2012, courtesy of Jerome Decq via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio.
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