Methane and the disturbed carbon cycle
Recently Ugo Bardi raised the matter of methane and the fact that compared with geological history, the present level in the atmosphere of this potent “greenhouse-gas” is exceptionally high. We see methane bubbling from the arctic margins. We know the present level is around 1800 parts per billion (1.8ppm); more than 2.5-fold the pre-industrial level. We know this rise has been sudden and that most of it occurred in the 20thC up to about year 1990, and that interestingly for a rapidly oxidised molecule, this high level has been sustained, and lately has begun to increase again. After a brief discussion with Ugo, I decided to attempt an update of my own knowledge.
May 1, 2012