New research by WHRC Associate Scientist Jonathan Sanderman and Australian co-authors published in Nature Climate Change shows that erosion is a previously unsuspected contributor to climate change. Erosion is a natural process that continually shapes the land surface. Land use and land use change have accelerated erosion rates up to 100 times over natural levels, creating situations such as the dust bowl of the 1930s.
Accelerated erosion due to agricultural management is one of the greatest threats to food security and soil sustainability. There has been a lot of research both quantifying erosion and providing solutions to mitigate erosion especially in agricultural settings. However, erosion doesn’t just remove soil, it also removes carbon contained in that soil. In fact, erosion removes the uppermost surface soil which also contains the greatest concentration of carbon.
Sanderman and his co-authors estimate that globally erosion is removing between 0.3 and 1.0 billion tons of soil carbon per year. This flux is equivalent to 16-55% of the annual greenhouse gas flux due to agriculture globally.
Despite the size of this carbon flux, erosion is almost universally ignored in regional and global carbon models. “By assuming a static land surface, earth system models apportion all soil carbon losses to a flux of carbon dioxide to the atmosphere,” says Dr. Sanderman. This new research demonstrates that 18-27% of the modeled soil flux to the atmosphere may in fact be lost laterally due to wind and water erosion. “If this carbon isn’t immediately going to the atmosphere then we need to do a better job tracking its fate on the land or into aquatic ecosystems,” adds Dr. Sanderman.
Accurate predictions of future carbon fluxes are critically needed to design effective climate mitigation strategies and this research suggests that recognizing soil erosion in these models would make a major improvement in our ability to predict future carbon fluxes.
WHRC is an independent research institute where scientists investigate the causes and effects of climate change to identify and implement opportunities for conservation, restoration and economic development around the globe.