Sustainability Column: The Importance of Soil as a Carbon Sink

One of the most prominent environmental issues today is climate change and the amount of carbon that is being released into the atmosphere. Most of the conversations on climate change revolve around the carbon that is released by large corporations, as well as the carbon that is released from our vehicles throughout the day. However, there are other sources of carbon that can be just as important and just as easily affected by human behavior.

One of the most overlooked sources of increased carbon is from carbon that is stored in soils around the planet. In the past, greenhouse gases that were released from soils due to agricultural or other reasons were often offset by the sequestration of CO2 by grasslands and forests, making the carbon flux from soils roughly neutral. However, in recent years and in the future, more invasive and aggressive agricultural processes and other anthropogenic actions will likely turn soils into a significant source of carbon and other greenhouse gases, further contributing to climate change.

A study by Corneilus Oertel et al. has found that the number of greenhouse gases that are emitted from soils far outweighs the amount that is emitted from fossil fuel consumption. Land use and land cover changes are the most influential on greenhouse gas emissions from soils, such as forest land being converted into agricultural land. Within the first 30 years of this convergence, 30 to 35 percent of the carbon that is stored in the top seven centimeters of the soil is emitted into the atmosphere.

Not only do our land use practices affect the emissions from soils, but the entire process of climate change creates a positive feedback loop for an increase in soil emissions. Colder soils are able to store more carbon, and permafrost soils in particular store a great amount. However, as the world becomes warmer due to climate change, these permafrost soils are warming, thawing and emitting their stored carbon into the atmosphere. Because of this, soil emissions will act as positive feedback for climate change, as the warmer the planet gets due to climate change, the more carbon will be released from warming soils. This carbon will then contribute even further to climate change.

While it is true that natural processes such as erosion and weathering can affect soil emissions, the large majority of recent emissions and future emissions will be due to anthropogenic activities. In order to prevent a greater increase in soil emissions, which would only increase the effects and amount of warming, we must be more wary of converting forest and grassland ecosystems into agricultural areas, as these processes influence soil emissions. We must also be more conscious of all of the ways in which we are influencing the health of the planet, and not only in the most prominent ways. Factors such as soil emissions may not be the leading causes of climate change, but they are still important issues that contribute to it and that we influence every day.

Contact Ethan Reiser at [email protected].