By Robert Krier, InsideClimate News
When climate scientists try to estimate how much the Earth will warm due to increasing levels of greenhouse gases in the atmosphere, a key consideration is the role of plants and soils. The more carbon they absorb, the more they reduce the global warming potential.
But recent studies indicate that assumptions about plants' and soils' capacity in the so-called "carbon cycle" may be overly optimistic. If these studies are correct, even bigger cuts in greenhouse gas emissions will be needed to prevent drastic, irreparable climate shifts.
Not only is it possible that plants won't be able to absorb as much carbon as climate models currently project, but plants' response to the carbon cycle could actually amplify global warming, Paul Higgins and John Harte write in the November edition of the Journal of Climate.
It all comes down to mobility.
Carbon dioxide is recognized as critical for photosynthesis, so the more there is in the atmosphere, the more there is available for plant growth. As Earth's climate warms, the theory has been that trees and other plant communities would treat the added CO2 as fertilizer and grow bigger and faster.