‘Nature cannot self-correct entirely against climate change …’
By Summit Voice
FRISCO — Massive reforestation efforts may help soak up a small part of the carbon dioxide generated by fossil fuel combustion, but it’s not a panacea for increasing concentrations of heat-trapping greenhouse gases.
Most widely accepted climate models have probably been over-estimating the ability of forests to absorb carbon from the atmosphere because the models do not represent the responses of soil microorganisms correctly, according to scientists with Northern Arizona University.
Their 11-year study showed that, contrary to expectations, high CO2 levels didn’t significantly increase carbon uptake. Plants did contain more carbon when CO2 levels were increased, but the soil actually lost carbon due to microbial decomposition; both factors essentially balanced one another out.
“Nature cannot ‘self-correct’ entirely against climate change, and the scientific community has been both overestimating the impact of plants and underestimating the impact of soil microorganisms in how they absorb CO2 and ultimately impact global warming,” said Bruce Hungate, director of the Center for Ecosystem Science and Society at NAU and lead author on the study, published online in the journal New Phytologist.
“Models of land ecosystems need to be revised to represent microbial responses explicitly,” Hungate said. “They’re the carbon balance ‘trump card,’ reversing the effect of plants on total carbon storage.”
According to Hungate, the tests confirmed that although soil microorganisms are microscopic, they are just as important as plants in determining carbon storage by ecosystems.