Digital techniques to monitor soil organic carbon

The snowiest winters. Catastrophic floods and droughts. Climate change impacts lives across the world in drastic and unpredictable ways. This unpredictability also extends to the more subtle yet still important effects of climate change. For example, it is uncertain how climate change will affect soils and their ability to support productive farms or healthy natural ecosystems.

In a new study, researchers used digital techniques to predict how one vital soil characteristic, soil organic carbon, may be altered by climate change. “Soil organic carbon is a major determinant of soil health,” says Jonathan Gray, lead author of the study. “It influences many chemical, physical, and biological properties of the soil, such as fertility and water holding capacity.” Gray is a senior scientist at New South Wales Office of Environment & Heritage in Australia and also undertaking doctoral studies at the University of Sydney.

The researchers used 12 climate change models to predict how soil organic carbon levels vary with climate change. The models used in the study reflected a full range of projected global climate outcomes. They were also applicable to the specific study region of New South Wales in southeast Australia. Results were varied. “A majority of models showed a decline in soil organic carbon with climate change,” states Gray. “But a few of the models actually predicted an increase.”

Why the different predictions? Gray attributes it to uncertainties within the climate change models. “We need more consistency between climate change projections before we can confidently predict how soil organic carbon levels will behave,” he says. The researchers also discovered that the extent to which soil organic carbon changes varied across soil types, current climate, and land use regimes.