Researchers may have been overestimating the degree of warming that the Earth will experience in the future. This has been revealed by studies of the release of carbon dioxide back into the atmosphere from the soil, a process known as soil respiration. A team at the University of Oklahoma spent a year artificially warming areas of the prairie at a fixed level above the air temperature and comparing the results with unheated areas.
Over the course of the year, the rate at which CO2 was released through the activity of fungi, such as mushrooms, was no greater in the warmed areas than in the unheated soils.This is the opposite of the current theory that says the hotter it gets, the faster soil pumps out CO2. For every 10 degrees that temperatures rise, CO2 emissions from soils were thought to double. But the team concluded that the soils? organisms quickly adjusted to higher temperatures.
Additional data suggests that the prairie grasses in the heated areas thrived under the additional warmth, meaning that that the world?s grasslands may soak up more CO2 than they give off, according to Linda Wallace, a plant ecologist at the University of Oklahoma. ?This is good news on a global basis,? she says. ?Grasslands cover a such a huge proportion of the terrestrial portion of globe. We?d been kind of discounting them, saying that as things warm up, they would become carbon sources. But in reality, these grasslands could become carbon sinks,? meaning that they would soak up carbon, removing it from the atmosphere and lessening the greenhouse effect.
Long-term experiments have already shown that, faced with increased concentrations of CO2, trees go through a relatively short ?growth spurt,? then their growth rate slows as they become acclimatized to higher CO2 levels, according to Lindsey Rustad, a soil ecologist with the U.S. Forest Service.
These studies show that the Earth may be more resilient that we thought, and better able to cope with the increasing temperatures brought on by excessive carbon dioxide emissions.
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