Researchers at the University of Toronto have published findings in the science journal, Nature Geoscience, that show global warming actually changes the molecular structure of organic matter in soil.

“Soil contains more than twice the amount of carbon than does the atmosphere, yet, until now, scientists haven’t examined this significant carbon pool closely,” says M J. Simpson, Ass. Professor of Environmental Chemistry at UTSC. “Through our research, we’ve sought to determine what soils are made up of at the molecular level and whether this composition will change in a warmer world.”

Organic matter is what makes soil fertile and able to support plant life, an essential for agriculture. Organic matter holds water in the soil and prevents erosion and the processes of decomposition of soil organic matter provide plants and microbes with the energy source and water they need to grow, and carbon is released into the atmosphere as a by-product of this process. Warming temperatures are expected to speed up this process which will increase the amount of CO2 that is transferred to the atmosphere.

“From the perspective of agriculture, we can’t afford to lose carbon from the soil because it will change soil fertility and enhance erosion” says Simpson. “Alternatively, consider all the carbon locked up in permafrost in the Arctic. We also need to understand what will happen to the stored carbon when microbes become more active under warmer temperatures.”