The Dirt on CO2

Carbon is an element found in all living things on earth. It is in plants, animals, micro-organisms, people, and soils. Most often, however, we hear about carbon in its oxidized form (CO₂) because there has been a drastic increase in the emission of carbon dioxide over recent decades. Some of the carbon released into the atmosphere is taken up by plants, some of it gets stored in the oceans, while the rest stays in the atmosphere. When carbon is stored in one of these forms it is called “carbon sequestration.”  There is, however, another place where carbon is stored, and it is right beneath your feet.

There is more carbon stored in the world’s soils than there is in the earth’s atmosphere and plant-life combined. How does carbon get into the soil? Well, it starts with photosynthesis. Photosynthesis is the process where plants use sunlight and CO₂ to produce their own food source (the by-product of this is oxygen). The excess carbon that plants don’t use passes through the root system and is then used to help feed soil organisms. Here, the carbon becomes stored in the soil organic matter. Soil organic matter is what turns “dirt” into soil. High soil organic matter means better water-holding capacity, better soil structure, and better fertility for plants. In order to make this entire cycle function, however, you’ve got to have a healthy soil and plant-life to start with.

Researchers have found that cultivated soils around the world have lost upwards of 70% of the carbon they once stored. When soil is turned over, the carbon stored in the soil organic matter is oxidized and returned back to the atmosphere as CO₂. When you consider that only 3% of North America’s tallgrass prairies remain intact, you can begin to imagine how much carbon has been lost from soils in the U.S. alone.

This trend, however, can be reversed. Restoring soil can provide an opportunity to restore this great carbon sink, while also improving productivity to help feed our growing population. Researchers believe that restoring the world’s degraded soil ecosystems can have the potential to store up to 3 billion tons of carbon each year. When translated into CO₂ emissions, this equates to about 34% of the carbon dioxide released from fossil fuel emissions each year.

A few examples of practices that can improve soil health and increase carbon storage include: replanting and restoring degraded areas, planting cover crops, pasture management, conservation tillage, and erosion control. These practices have been used locally with great success, and they are becoming more widespread throughout the country due to the many benefits they provide to the landscape and the landowner.

Restoring the world’s soils is not a small undertaking, but soil is arguably one of our most important resources, and is therefore worth managing carefully. Furthermore, as CO_s emissions continue increasing in coming decades, restoring our landscapes to help carbon sequestration might be one of the most viable and sensible solutions to help mitigate the amount of this gas that is released into the atmosphere. We have an opportunity to take advantage of the billions of tons of carbon being emitted around the world, and we can put it back into the ground where it’s of better use to us all.

Written by: Ethan Kunard