A new publication by ERI’s dr. Lonneke Goddijn-Murphy with co-authors in Nature Communications is out:
Revised estimates of ocean-atmosphere CO2 flux are consistent with ocean carbon inventory (2020)
Watson, A.J., Schuster, U., Shutler, J.D., Holding, T., Ashton, I.G.C., Landschützer, P., Woolf, D.K & Goddijn-Murphy, L. (2020), Nature Communications 11, 4422. https://doi.org/10.1038/s41467-020-18203-3
Half of the carbon dioxide we emit doesn’t stay in the atmosphere but is taken up by the oceans and land vegetation “sinks”. There now exists a large database of near-surface carbon dioxide measurements (the “Surface Ocean Carbon Atlas”, www.socat.info ) that can be used to calculate the flux of CO2 from the atmosphere into the ocean. However, there is a catch: the measurements are not made right at the ocean surface where they are needed, but from a few metres down. Previous studies have ignored small temperature differences between the surface of and the sampling depth, but satellites can measure the temperature right at the ocean surface, and our study uses satellite data to correct the temperatures. When we do this we find it makes a big difference, and we calculate a substantially larger flux going into the ocean.
Our revised estimate agrees much better than previously with an independent method of calculating how much carbon dioxide is being taken up by the ocean – that method makes use of a global ocean survey by research ships over decades, to calculate how the inventory of carbon in the ocean has increased. These two “big data” estimates of the ocean sink for CO2 now agree pretty well, which gives us added confidence in them.”
Animations on the data results are available through:
Spatial map and plot animation
Caption: Left, the mean monthly ocean to atmosphere carbon flux corrected for cool water and salty skin. Negative flux (in blue) indicates a flux of carbon into the ocean. Right, annual integrated global net carbon flux between the atmosphere and oceans for 1992 to 2018 with no corrections (yellow line), surface temperature corrections only (red line) and corrected for cool water and salty skin (blue line).
Spatial map animation only
Caption: The mean monthly ocean to atmosphere carbon flux corrected for cool water and salty skin. Negative flux (in blue) indicates a flux of carbon into the ocean.
