[ClearCase_guy]

After water vapour and carbon dioxide, methane is the most significant greenhouse gas, resulting in about one fifth of atmospheric warming caused by humans.

It's amusing when they quantify things that aren't happening.

[gleeaikin]

The reports I read suggest that methane is 20 times more potent than CO2 as a green house gas. Both are being exuded as the tundra/permafrost thaws.