17 Oct Methane

National Academy of Technologies of France (NATF)
2016

Strong variations of atmospheric concentrations of methane, a potent greenhouse gas, have accompanied glacial and interglacial periods. Such variations influence the timetable and magnitude of climate changes.
The report describes and analyses natural and human-related sources and sinks of atmospheric methane with particular attention to potentially massive emissions from thawing permafrost in Arctic wetlands and marine methane hydrates (clathrates). The methane fluxes between main reservoirs and the atmosphere is measured via ground-based networks or from outer space, allowing a better understanding of evolving atmospheric concentrations and interaction between sinks and sources.
As atmospheric methane is destroyed over time (half-life ~7 years), its CO2 equivalence, in terms of GHG-efficiency is not straight-forward, depending on the time-scale applied.  While increasing fossil fuel exploitation is an important methane source, emissions could be limited at reasonable cost.  Feedbacks from wetlands and soils are more difficult to control.
A number of recommendations on how to limit methane release are made in areas such as agricultural practices, waste- and landfill management, biomass combustion, exploitation of coal, natural gas and oil. Carefully follow developments in boreal zones, especially regarding the possible exploitation of methane from permafrost and marine clathrates.

Group Leader: Jean-Claude André, Former Director of the European Centre for Research and Advanced Training in Scientific Computing (CERFACS), and NATF Fellow