Ocean carbon uptake largely underestimated
According to new research, the world’s oceans absorb much more carbon than most scientific models suggest.
Previous estimates of the movement of carbon (known as “flux”) between the atmosphere and oceans did not take into account temperature differences at the surface and a few meters below it.
The new study, conducted by the University of Exeter, includes this – and finds significantly higher net carbon flux into the oceans.
It calculates CO2 Fluxes from 1992 to 2018 with up to twice as much net flux found at certain times and locations as uncorrected models.
“Half of the carbon dioxide we emit does not stay in the atmosphere but is absorbed by the oceans and land vegetation,” said Professor Andrew Watson of the Exeter Global Systems Institute.
“The researchers have compiled a large database of near-surface carbon dioxide measurements – the“ Surface Ocean Carbon Atlas ”- which can be used to calculate the flow of CO2 from the atmosphere into the ocean.
“However, previous studies that have done this have ignored small temperature differences between the sea surface and the depth of a few meters at which the measurements are taken.
“These differences are important because the solubility of carbon dioxide is very dependent on temperature.
“We used satellite data to correct for these temperature differences and when we do that it makes a huge difference – we get a much larger river flowing into the ocean.
“The difference we calculated in ocean uptake is about 10 percent of global fossil fuel emissions.”
Dr. Jamie Shutler of the Center for Geography and Environmental Sciences on Exeter’s Penryn campus in Cornwall added, “Our revised estimate is much more consistent than before with an independent method of calculating the ocean’s carbon uptake.
“This method uses a global ocean survey carried out by research vessels over decades to calculate how the carbon stocks in the ocean have increased.
“These two big data estimates of the ocean sink for CO2 Now I pretty much agree which gives us extra confidence in her. ”
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Reference: “Revised estimates of CO in the ocean atmosphere2 Flux Corresponds to the Carbon Inventory of the Oceans “by Andrew J. Watson, Ute Schuster, Jamie D. Shutler, Thomas Holding, Ian GC Ashton, Peter Landschützer, David K. Woolf and Lonneke Goddijn-Murphy, September 4, 2020, Communication with nature.
DOI: 10.1038 / s41467-020-18203-3
The authors of the paper include scientists from Herriot-Watt University, the University of the Highlands and Islands and the Max Planck Institute in Germany.
The study’s funders included the Royal Society, the Natural Environment Research Council, and the European Space Agency.
The paper published in Communication with natureis titled: “Revised estimates of the CO2 flux in the ocean atmosphere are consistent with the carbon inventory of the oceans.”
