New Software Measures Agriculture’s Carbon Footprint

Taylor Hillman Energy, Environment

Carbon Footprint
Agriculture is one human activity that must be factored in to climate change, both as an emitter and an absorber of greenhouse gas.

But how can farmers know their farm’s carbon footprint? Not just a qualitative idea, mind you, but the actual shoe size?

USDA’s COMET-Farm and its more recent and high-cut cousin, COMET-Planner, can help. The free, online tools allow farmers and ranchers to quantify their atmospheric outputs (emissions) and carbon benefits (sequestration) based on site-specific soils, crops, and management practices.

Farms have frequently been seen as sources of carbon emissions traced to operations such as tillage, fertilizing and methane from livestock. But farms also grow prodigious amounts of plant life–and that pulls carbon dioxide out of the atmosphere.

Balancing agriculture’s net emissions and sequestrations has been a question mark. That’s where the COMET tools come in, says Adam Chambers, one member of the team that developed the online tools. Chambers is with the Energy and Environmental Markets Team of USDA’s Natural Resources Conservation Service (NRCS). NRCS joined forces with Colorado State University to build the tools. California’s Department of Food and Agriculture, Marin Carbon Project and the California Farm Bureau lent their expertise to make the tools more user-friendly.

According to Chambers, farms improve their atmospheric benefits by implementing conservation practices such as reduced or no-tillage, cover crops, riparian buffers, hedgerows and more than 30 NRCS conservation practices that are “climate-smart,” and can be calculated using the COMET tools. “The practices have long been recognized as good for soil, water and habitat,” says Chambers, “now they are getting credit for keeping carbon (a.k.a. soil organic matter) underground too.”

The COMET tools allow farmers to play with “what if” scenarios, says Chambers. “What if you change from conventional tillage to reduced till? What if you add a quarter mile windbreak–or a buffer strip along a field or stream? What if you change your form of fertilizer or the way you apply it? You can get a quantitative idea of how these can create atmospheric benefits on your farm or ranch,” he says.

“Some farmers may be merely curious about their carbon footprint while others may be interested in tapping into carbon markets,” says Chambers. While current prices are quite low, future conditions could change this, Chambers says. “This could be a further incentive to ‘farm for carbon’.”

Carbon sequestration not only helps the atmosphere, it also aids fertility and water holding capacity. Restoring carbon to the underground ecosystem feeds the busy microbial community that recycles old plant matter into nutrients and builds water-holding capacity. Nowhere is such vital activity more important than in an arid state like California,” says Chambers.

Farmers who use the COMET tools will end up with a report that uses the same quantification methodologies as the US Greenhouse Gas Inventory–a report submitted to the United Nations on an annual basis. The report contains individual chapters on agriculture and land uses, says Chambers.

The most common greenhouse gases emitted by agriculture are carbon dioxide, nitrous oxide, and methane, says Chambers. “We know that healthy soils and healthy biomass are very capable of removing large amounts carbon from the atmosphere and storing (or sequestering) that carbon.”

For more information or to play with the online Comet tools see Comet-Farm for a complete greenhouse gas analysis, or go to Comet-Planner for a quicker, big-picture evaluation.

Since its inception in 1935, NRCS has worked in partnership with private landowners and a variety of local, state and federal conservation partners to deliver conservation based on specific, local needs. Please visit for more information about NRCS.