This is a bit above my pay grade. Perhaps Dr. S will opine. The graf that stopped me cold:
In a discovery that has left climate scientists gasping, researchers have found that the earth's vegetation is churning out vast quantities of methane, a greenhouse gas far more potent even than CO2. This is not a product of trees and plants rotting, which everyone already knew was a source of methane; it is an entirely natural side-effect of plant growth that scientists had somehow missed. Yet it is by no means trivial: preliminary estimates suggest that living trees and plants account for about 10 to 30 per cent of the methane entering the atmosphere.So it wasn't my SUV afterall.