As the planet warms, soil decomposition rates are accelerating, allowing more carbon to escape into the atmosphere. Photo by PickPik
Nov. 2 (UPI) -- If Earth's climate warms 2 degrees Celsius, new research predicts 230 billion tons of carbon will be released from the planet's soil.
According to the study, published Monday in the journal Nature Communications, rising global temperatures are accelerating decomposition rates and reducing the amount of time carbon remains sequestered in the soil.
When researchers at Exeter University modeled the effects of global warming on decomposition and "soil carbon turnover" -- the amount of time carbon spends in the soil -- they found 2 degrees Celsius of warming above pre-industrial levels will trigger the release of an extra 230 billion tons of carbon.
For comparison, the United States has emitted roughly 115 billion tons of carbon over the last century.
"Our study rules out the most extreme projections -- but nonetheless suggests substantial soil carbon losses due to climate change at only 2 degrees Celsius warming, and this doesn't even include losses of deeper permafrost carbon," Sarah Chadburn, research fellow at Exeter and co-author of the new study, said in a news release.
To create their prediction model, researchers updated the Earth System Models with new observational data related to decomposition rates in the soil.
"We investigated how soil carbon is related to temperature in different locations on Earth to work out its sensitivity to global warming," said lead study author Rebecca Varney, climate scientist at Exeter.
Previous attempts to predict the effects of global warming on soil carbon have yielded uncertainty ranges in excess of 120 billion tons of carbon, but Varney and company were able to reduce the uncertainty to a plus-minus range of 50 billion tons of carbon.
"We have reduced the uncertainty in this climate change response, which is vital to calculating an accurate global carbon budget and successfully meeting Paris Agreement targets," said study co-author Peter Cox, professor at Exeter's Global Systems Institute