The Montreal Protocol has been extremely successful in limiting the emissions of ozone depleting substances such as CFCs. As we’ve shown in previous papers, emissions and atmospheric abundances of these compounds have declined in recent decades. Since 2010, the Protocol mandates that there should be essentially no new production of CFCs for emissive use anywhere in the world. Therefore, our finding, published in Nature, that the rate at which CFC-11 is declining in the atmosphere has slowed since 2013 was surprising. Using atmospheric observations from the National Oceanic and Atmospheric Administration, we show that about 10,000 tonnes of this compound are being emitted to the atmosphere each year. This result has since been supported by data from the Advanced Global Atmospheric Gases Experiment. There have been some good summaries of the work in the New York Times, Washington Post, Guardian, etc. Since the paper came out, work by the Environmental Investigation Agency has shown that CFC-11 may still be produced in China. The next step for us is to use atmospheric observations to try to narrow down the location…
Atmospheric Scientist at the University of Bristol