Martyn P. Chipperfield

Abstract Observations have demonstrated the ubiquity of short-lived halogens (SLHs)—defined as organic and inorganic chlorine, bromine and iodine compounds with an overall atmospheric lifetime of less than 6 months—in the global atmosphere. They are primarily emitted naturally from the ocean, cryosphere, volcanoes, salt lakes and the biosphere. However, unregulated anthropogenic sources are increasingly contributing to their atmospheric loading.

Ongoing large ozone depletion in the polar lower stratospheres: the role of increased water vapour The very low temperatures of the polar lower stratosphere lead to the efficient seasonal depletion of ozone following the formation of polar stratospheric clouds (PSCs) and heterogeneous chlorine-activating reactions on their surfaces.

Abstract The amount of methane released to the atmosphere from the Nord Stream subsea pipeline leaks remains uncertain, as reflected in a wide range of estimates1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18. A lack of information regarding the temporal variation in atmospheric emissions has made it challenging to reconcile pipeline volumetric (bottom-up) estimates1,2,3,4,5,6,7,8 with measurement-based (top-down) estimates8,9,10,11,12,13,14,15,16,17,18.