Soil leaks up carbon when it warms up but a new research suggests that the soil may release more carbon than previously believed as temperatures increase. This can potentially create a dangerous feedback loop that may aggravate global warming.
While most of the studies on climate change are conducted at atmospheric levels, the findings of a new study are based on 26 years’ worth of observations in a Massachusetts hardwood forest, where scientists artificially heated certain sections of the soil and measured the amount of carbon released.
Study researcher Jerry Melillo, from the Marine Biological Laboratory, and colleagues studied three different types of forest plot. In one set of plot, they installed heating cables in the soil and heated them so the soil would be about 10 degrees warmer than the air around it. Heaters were also installed in the second set of plot but these were not turned on and the third set of plot was left untouched.
Analysis revealed that rising temperatures may cause a two-stage cycle characterised by the carbon output increasing for several years and then levelling off, which can be explained by soil microbes adjusting to the warmer condition.
In the study, carbon released from heated soil rose dramatically in the first decade but the effect disappeared. After about seven years, the researchers observed another increase in carbon from the heated plots after readjustment.