MIT News March 15, 2021
The levels of CFC-11 in the atmosphere have been steadily declining since 2010 under the Montreal Protocol, ocean absorbing about 5 to 10 percent of all manufactured CFC-11 emissions. A team of researchers in the US (MIT, Colorado State University, UC Santa Barbara, NASA Goddard Space Flight Center) looked to pinpoint when the ocean would become a source of the chemical, and to what extent the ocean would contribute to CFC-11 concentrations in the atmosphere. Through a hierarchy of models to simulate the mixing within and between the ocean and atmosphere, and adding anthropogenic emissions of CFC-11 that had previously been reported through the years to the model, they ran the model forward in time, from 1930 to 2300, to observe changes in the chemical’s flux between the ocean and the atmosphere. They observed that the ocean began to emit more of the chemical than it absorbed, beginning around 2075. By 2145, the ocean would emit CFC-11 in amounts that would be detectable by current monitoring standards. Knowing the exact drivers of the ocean’s reversal will require more detailed models, which the researchers intend to explore. Video …read more. Open Access TECHNICAL ARTICLEÂ
Model validation of CFC-11 atmospheric abundances compared to CFC-11 atmospheric surface data. Credit: PNAS March 23, 2021 118 (12) e2021528118