Methane is less prevalent in the atmosphere than fellow greenhouse gas carbon dioxide (CO2), but it presents more difficult challenges for researchers attempting to study it. Most producers of CO2 can easily estimate their carbon footprint—eliminating the need for close tracking. For example, power plants burning fossil fuels know, to a high degree of accuracy, how much CO2 is produced by their operations. Furthermore, the sources of CO2 are easy to pin down. The CO2 produced by burning coal in a furnace is spewed out the attached smokestack.
Methane emissions, by contrast, are more difficult to quantify. Read more.