Derived from the soil database, FAO has produced a global Carbon Gap Map that allows for the identification of areas where soil carbon storage is greatest and the physical potential for billions of tons of additional carbon to be sequestrated in degraded or nutrient-poor soils. Because of their enormous potential to store carbon, soils can become the key to mitigating climate change. Soil information has often been the one missing information layer, the absence of which has added to the uncertainties of predicting the potential for and constraints to food and fibre production as well as the capacity of soils to hold carbon and to act as a sink.
Until now, most efforts to use agriculture to manage greenhouse gases have involved above-ground sequestration, primarily through planting trees, since the amount of carbon that can be sequestered in this way is substantial. However, planting trees entails risks, because the carbon stored in them can be destroyed by fires or natural degradation processes.
This is why there is a growing interest in finding ways to increase carbon sequestration in soils, most notably biochar. Biochar, also known as agrichar, aims to cure degraded and nutrient-poor soils by adding recalcitrant char to them, which acts as a stable and permanent carbon sink. Biochar offers one of the most drastic solutions to mitigating climate change because the char can be sequestered safely and easily for centuries, possibly millennia.
Caked dried mud at Toadstool Geologic Park (Nebraska), photo by Brian Kell, who has generously released the image into the public domain via Wikimedia Commons