Understanding the glacial methane cycle.

ABSTRACT: Atmospheric methane (CH₄) varied with climate during the Quaternary, rising from a concentration of 375 p.p.b.v. during the last glacial maximum (LGM) 21,000 years ago, to 680 p.p.b.v. at the beginning of the industrial revolution. However, the causes of this increase remain unclear; proposed hypotheses rely on fluctuations in either the magnitude of CH₄ sources or CH₄ atmospheric lifetime, or both. Here we use an Earth System model to provide a comprehensive assessment of these competing hypotheses, including estimates of uncertainty. We show that in this model, the global LGM CH₄ source was reduced by 28-46%, and the lifetime increased by 2-8%, with a best-estimate LGM CH₄ concentration of 463-480 p.p.b.v. Simulating the observed LGM

SUBMITTER: Hopcroft PO 

PROVIDER: S-EPMC5321756 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature