The effort to reduce the amount of carbon in the atmosphere is primarily focused on the sources of carbon, such as emissions from the burning of fossil fuels. This can be called a supply-side approach. However, there is also the important issue of carbon sinks, which are termed demand-side approaches to the problem.
The greatest sink for carbon is soil. Estimates are that 2,500 billion tons of carbon resides in soil, compared with 800 billion tons in the atmosphere and 560 billion tons in living things. However, the dramatic reduction of carbon-rich environments such as the vast North American tall grass prairie has greatly changed how much carbon is stored in the soil. In all, the world’s cultivated soils have lost between 50 and 70 percent of their original carbon content, most of which has oxidized to form CO2.
There are many reasons to want to restore carbon to our soil. Apart from offsetting the effects of fossil fuel emissions, carbon-rich soils are the soils that sustain crops and support living things. There are many strategies for increasing the carbon content of soil. These include replanting degraded areas, increased use of mulching instead of burning biomass, erosion control, and restoration of mangroves, salt marshes, and sea grasses.
The battle to reduce carbon in the atmosphere must be fought on multiple fronts. Restoring the soils of degraded and desertified ecosystems has the potential to a store a significant fraction of our carbon emissions. Soil should be part of any agenda to address climate change.
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Soil as Carbon Storehouse: New Weapon in Climate Fight?
Photo, taken May 24, 2013, courtesy of the United Soybean Board via Flickr.
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Earth Wise is a production of WAMC Northeast Public Radio.