A Significant Advancement in Modeling the Global Methane Cycle

This article is a JAMES Editor’s Highlight in EOS (AGU’s science news magazine), published by Jiwen Fan, 8 September 2022 – original source here.

The graphic summarizes the global mean full-cycle methane budget depicted as decadal means that are centered around the year shown for the individual bars as represented in the new model. The individual budget terms have been calculated with UKESM1-ems and are shown at 50-year intervals over the historic period (1850–2014). The numbers in this figure are limited to the dominant fluxes in the global methane cycle as represented in UKESM1-ems. Credit: Folberth et al. (2022), Figure 1.

Methane (CH4) is a key atmospheric trace gas for two important reasons: it is a powerful greenhouse gas, second only to carbon dioxide, and it is a pollutant that plays a critical role in the formation of ozone in the troposphere near the surface, a phenomenon also known as ‘summer smog’. Since the mid-twentieth century, anthropogenic emissions have become the dominant source of methane pollution. Therefore, methane has been targeted as a key component in climate and air quality mitigation strategies.

Folberth et al. (2022) describe a newly developed methane emission-driven process model, representing the global methane cycle within the United Kingdom Earth System Model Version 1.0 (UKESM1) framework. They evaluate the model’s performance against available observations of methane and methane emissions. The authors demonstrate that the new methane emission-driven model simulates all the components of the methane cycle within observational uncertainty.

UKESM1-ems (methane emission-driven UKESM1) represents one of the first Earth system models to simulate the global methane cycle fully interactively with unprecedented detail. The significant step in this development is the inclusion of feedbacks of the methane cycle within the Earth system. This new capability advances the international climate science community’s ability of providing essential evidence to underpin climate mitigation policy by targeting methane reduction strategies and evaluating their impacts on climate and the Earth system.

Folberth, G. A., Staniaszek, Z., Archibald, A. T., Gedney, N., Griffiths, P. T., Jones, C. D., et al. (2022). Description and evaluation of an emission-driven and fully coupled methane cycle in UKESM1. Journal of Advances in Modeling Earth Systems, 14, e2021MS002982. doi: 10.1029/2021MS002982

About the authors
Gerd Folberth, Fiona O’Connor, Nicolas Gedney, Chris Jones and Andy Wiltshire are all researchers at the MetOffice Hadley Centre (UK) and work in our Workpackage 4/5 on the coupling of the methane cycle (which Fiona co-leads).