Methane studies in ice cores

Abstract

This article presents state-of-the-art atmospheric methane reconstruction based on ice core studies. Starting with a biogeochemical overview of the methane cycle, it presents and discusses the anthropogenic impact on atmospheric CH4. It then introduces the processes of gas diffusion in firn and trapping in ice and their impact on methane reconstructions. The trends of this greenhouse gas and its isotopic composition over the last two thousand years, the Holocene, the Last Glacial and deglaciation, and the last eight glacial–interglacial cycles are summarised, and likely drivers are discussed. Analytical techniques and non-atmospheric signal artifacts are also briefly described.