Why are we interested in measuring Methane?
Atmospheric methane (CH4) is the second most important greenhouse gas after carbon dioxide (CO2) that is modified by mankind, both directly through emissions (oil and gas extraction and combustion) and indirectly (via changing land use). There are potential dangerous positive feedbacks with a warming climate, for example permafrost thawing in the Arctic, changing patterns of wetland inundation and possibly, on the longer term, clathrate release from the seafloor. Methane is also a potential precursor of tropospheric ozone, which is a toxic regional pollutant that negatively impacts human health, agriculture and ecosystem services, and is itself a greenhouse gas, contributing to global warming. In spite of its importance, huge gaps still exist in our knowledge of regional and global methane emissions, and it is disconcerting that we still cannot unequivocally attribute the rise of methane since 2007 to specific emission sectors or regions.
Methane continues to increase steadily in the atmosphere as too few efforts are made worldwide to mitigate its anthropogenic emissions, although technologies exist (e.g. fixing gas leaks, covering landfills, harvesting biogas from the anaerobic digestion of agricultural waste). This is despite the fact that a reduction of CH4 emissions would have a much more immediate impact on climate than a reduction of CO2 emissions, thanks to methane’s relatively short atmospheric lifetime of only nine years due to its natural oxidation in the atmosphere.