1. Measurements of Atmospheric Methane and 13C/12C of Atmospheric Methane from Flask Air Samples
2. ES-2. In addition, 567.6 million metric tons of methane (CO 2 equivalent), 318.2 million metric tons of N 2 O (CO 2e ) and much smaller amounts of the other GHGs were emitted. Id. Since 1990 methane and nitrous oxide emissions have decreased, but CO 2 emissions have increased by an annual average of 0.85 percent;Id;ES-4, tbl