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Rapid increase in dichloromethane emissions from China inferred through...

An, M., L. Western, D. Say, L. Chen, T. Claxton, A. L. Ganesan, R. Hossaini, P. B. Krummel, A. Manning, J. Mühle, S. O’Doherty, R. G. Prinn, R. Weiss, D. Young, J. 1. ✉. Hu, B. Yao, and M. Rigby (2022), Rapid increase in dichloromethane emissions from China inferred through atmospheric observations, Nature, doi:10.1038/s41467-021-27592-y.

With the successful implementation of the Montreal Protocol on Substances that Deplete the Ozone Layer, the atmospheric abundance of ozone-depleting substances continues to decrease slowly and the Antarctic ozone hole is showing signs of recovery. However, growing emissions of unregulated short-lived anthropogenic chlorocarbons are offsetting some of these gains. Here, we report an increase in emissions from China of the industrially produced chlorocarbon, dichloromethane (CH2Cl2). The emissions grew from 231 (213–245) Gg yr−1 in 2011 to 628 (599–658) Gg yr−1 in 2019, with an average annual increase of 13 (12–15) %, primarily from eastern China. The overall increase in CH2Cl2 emissions from China has the same magnitude as the global emission rise of 354 (281−427) Gg yr−1 over the same period. If global CH2Cl2 emissions remain at 2019 levels, they could lead to a delay in Antarctic ozone recovery of around 5 years compared to a scenario with no CH2Cl2 emissions.

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This work has benefited from the technical expertise of and assistance by the AGAGE (Advanced Global Atmospheric Gases Experiment) network including the Medusa GC/MS system technology, calibrations of CH2Cl2 measurements and network operation, as well as Dr. Martin Vollmer from Swiss Federal Laboratories for Materials Science and Technology. We acknowledge the support from members of Atmospheric Chemistry Research Group at University of Bristol. Measurements at the Mace Head, Trinidad Head, Ragged Point, Cape Matatula, and Cape Grim AGAGE stations are supported by the National Aeronautics and Space Administration (NASA) (grants NNX-16AC98G to MIT, and NNX16AC97G and NNX16AC96G to SIO).