Carbon stored in the world’s soils more vulnerable to climate change than expected

A press release from the University of Exeter: The response of soil microbial communities to changes in temperature increases the potential for more carbon dioxide to be released from the world's soils as global temperatures rise, scientists have revealed.

The potential for global warming to stimulate decomposition rates in soils, and thus release large quantities of carbon dioxide to the atmosphere, has long been considered to be one of the potentially most important positive feedbacks to climate change.

However, the results from more recent studies have suggested that responses within microbial communities could greatly reduce, or even eliminate, the potential for soil carbon losses under global warming.

This key idea was tested using soils collected from a thermal gradient from the Arctic to the Amazon rainforest. The results, published in Nature, show that, contrary to expectations, microbial community responses resulted in an overall increase, rather than a decrease, in the effects of temperature on rates of carbon dioxide release from soils.

Dr Kristiina Karhu of the University of Helsinki, and lead author of the paper, said: “Because soils store more than twice as much carbon than the atmosphere, changes in rates of decomposition and carbon dioxide release from soil could be very important. Our findings suggest that warming will increase the activity of soil microbes to a greater extent than was previously expected, which could have implications for future rates of climate change.”...

Some soil in the Netherlands, shot by FotoDutch , Wikimedia Commons, under the Creative Commons 3.0 license