Soils Help to Combat and Adapt to Climate Change

2015 International Year of Soils

Healthy soils provide the largest store of terrestrial carbon. When managed sustainably, soils can play an important role in climate change mitigation by storing carbon (carbon sequestration) and decreasing greenhouse gas emissions in the atmosphere. Conversely, if soils are managed poorly or cultivated through unsustainable agricultural practices, soil carbon can be released into the atmosphere in the form of carbon dioxide, which can contribute to climate change. The steady conversion of grassland and forestland to cropland and grazing lands over the past several centuries has resulted in historic losses of soil carbon worldwide. However, by restoring degraded soils and adopting soil conservation practices, there is major potential to decrease the emission of greenhouse gases from agriculture, enhance carbon sequestration and build resilience to climate change.

The carbon cycle is the exchange of carbon (in various forms) between the atmosphere, ocean, terrestrial biosphere and geological deposits. Most of the carbon dioxide in the atmosphere comes from biological reactions that take place in the soil. Carbon sequestration occurs when carbon from the atmosphere is absorbed and stored in the soil. This is an important function because the more carbon that is stored in the soil, the less carbon dioxide there will be in the atmosphere contributing to climate change.

Climate change represents a serious threat to global food security, not least because of its effects on soils. Changes in temperature and rainfall patterns can have a great impact on the organic matter and processes that take place in our soils, as well as the plants and crops that grow from them. In order to meet the related challenges of global food security and climate change, agriculture and land management practices must undergo fundamental transformations. Improved agriculture and soil management practices that increase soil organic carbon, such as afro-ecology, organic farming, conservation agriculture and agroforestry, bring multiple benefits. They produce fertile soils that are rich in organic matter (carbon), keep soil surfaces vegetated, require fewer chemical inputs, and promote crop rotations and biodiversity. These soils are also less susceptible to erosion and desertification, and will maintain vital ecosystem services such as the hydrological and nutrient cycles, which are essential to maintaining and increasing food production. The Food and Agriculture Organization of the United Nations (FAO) also promotes a unified approach, know as Climate-Smart Agriculture (CSA), to develop the technical, policy and investment conditions that support its member countries in achieving food security under climate change. CSA practices sustainability increase productivity and resilience to climate change (adaptation), while reducing and removing greenhouse gases whenever possible (mitigation).