Capturing carbon

By OWEN WALSH
Posted 1/15/20

Some experts visualize the climate crisis as one of imbalance. Humans consume energy by extracting carbon from the ground, burning it and letting its emissions escape into the atmosphere. Ideally, …

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Capturing carbon

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Some experts visualize the climate crisis as one of imbalance. Humans consume energy by extracting carbon from the ground, burning it and letting its emissions escape into the atmosphere. Ideally, these emissions would be balanced out by the amount of carbon the planet sucks out of the atmosphere. However, the level of carbon that we have been emitting into the atmosphere outweighs the amount that we take out of it. 

In addition to mitigating our greenhouse gas output by switching to alternative forms of energy, another attempt to balance the equation is known as carbon sequestration, carbon capture, or carbon dioxide removal. Carbon sequestration comes in a multitude of forms; this article will provide a brief introduction into how farming and forestry practices can help remove carbon from the atmosphere.

Farming

Agriculture has the potential to either increase or mitigate greenhouse gas emissions. Clearing wooded areas for farmland, nitrogen-based fertilizers, heavy machinery that burns coal, gasoline, diesel fuel and natural gas, and livestock fermentation all contribute to greenhouse gas emissions. In 2005, the Intergovernmental Panel of Climate Change attributed 10 to 12 percent of all emissions to agriculture.

Trading conventional farming practices for more sustainable methods can reverse agriculture’s effect on climate change, however. A major determinant in a farm’s overall sustainability is below the farmer’s feet, in the soil.

By using a number of strategies known as “conservation tillage,” farmers can mitigate the amount that soil carbon gets released into the atmosphere, while also improving their soil’s carbon sequestration abilities and reducing soil erosion. The following are some conservation tillage strategies:

Increase organic-matter levels in soil through the use of composted animal manures and cover crops.

Being careful not to overgraze fields, rotational grazing and seasonal use of rangeland.

Reduce the use of nitrogen-based fertilizer with cover crops and manure.

Improve soil conditions through the use of “biochar.” Made from controlled burning of organic material (biomass), biochar enhances soil structure while sequestering billions of tons of carbon annually and storing it for thousands of years.

Forestry

Forests play an important role in the lifecycle of the planet’s carbon, which can be found in the trunks, branches, foliage and roots of the trees in the forest. Forests’ other plant matter and soil also store carbon.

According to the U.S. Forest Service, forest growth and “afforestation” (the establishing of forests) offset U.S. fossil fuel emissions by 10 to 20 percent yearly. In 2010, U.S. forests and long-lived wood products contained 251 million metric tons of carbon. Forests do not solely extract carbon from the atmosphere, however. When trees die and decompose, much of the carbon stored in the wood naturally gets released back into the atmosphere. This process is accelerated by human-influenced forest loss, like deforestation and fires. In October 2017, a severe forest fire in California emitted as much carbon dioxide in a week as the motor vehicles of California released in a year.

The best forest management practices for storing carbon have been a point of debate among researchers. Here are some of the generally agreed upon strategies:

Avoid deforestation and facilitate regeneration of areas that faced forest fires.

Manage forests sustainably; this means increasing biodiversity, improving water quality and minimizing soil erosion.

Reforest areas where forests historically occurred.

Promote long-lived wood products, which can continue to store carbon, as opposed to materials like concrete that contribute to carbon emissions.

The Rodale Institute, based in Kutztown, PA, recommends that farmers and landowners learn how to sustainably plant and maintain trees in a way that efficiently sequesters carbon from the atmosphere, while adding value to their land. The institute advises considering factors like terrain, soil conditions, what kinds of trees to plant, when to plant and how to protect and maintain trees. You can contact your local forestry service for specific advice about planting trees on your land.

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