Speaker: Professor Paul Palmer (The University of Edinburgh)
Abstract: Observed changes in atmospheric methane this century on Earth and Mars have defied definitive explanation. On Earth, a hiatus in the atmospheric growth rate of methane during 2000-2007 was followed by an acceleration that has so far peaked in 2021 with an unprecedented value of 18.12 ppb/yr. Satellite data have provided some explanation for recent changes in atmospheric methane, quantifying the responsible regional combustion and natural emissions - some of which we are only just learning about. Meanwhile on Mars, the debate surrounding the possible detection of a seasonal cycle for atmospheric methane rumbles on with competing analyses using data collected by instruments aboard the Trace Gas Orbiter (TGO). In this presentation, I discuss what we have learnt about Earth’s methane budget from satellite data and explain why you should be concerned about a recently reported empirical relationship between changes in methane emissions from East Africa and the Indian Ocean Dipole index. I will also explain why non-methane atmospheric chemistry data collected by TGO instruments may hold the key to understanding changes in atmospheric methane on Mars.