Dr. Paul's Research Perspectives
Measuring soil carbon changes would allow farms to offset excess emissions of other enterprises
Cap-and-trade approach, used wisely, could drive carbon-sequestering activities on-farm and beyond.

By Paul Reed Hepperly, Ph.D.

November 16, 2007: In our atmosphere, carbon dioxide gas absorbs warmth and acts like a planetary blanket. When gasoline, oil, natural gas and/or coal are burnt, oxygen from our atmosphere combines with carbon in the fuel source to create carbon dioxide as a waste product. Since the Industrial Revolution, the intensified burning of fossil fuels has led to continually increasing carbon dioxide concentrations in the earth’s atmosphere. These have now surpassed all geologically recorded concentrations. How will this overabundance of greenhouse gas impact our climate? And what will be our fate on a much warmer planet?

One way to reduce carbon dioxide is the so-called “cap-and-trade” regulatory approach.

Advantages of cap-and-trade

Cap-and-trade is an administrative protocol for regulating air emissions and meeting environmental goals. This framework is based on methods developed for the reduction of sulfur dioxide emissions governed under the 1990 U.S. Clean Air Act. Under this approach, businesses were given reduction targets, such as a reduction of 50 percent emissions by 2010, and then were allowed to buy excessive reductions, or credits, from leaders in the field who had exceeded their overall targets.

This new free-trade approach has been effective in reducing emissions at a fraction of the cost of traditional non-market regulatory approaches. It rewards innovation and flexibility for businesses in their efforts to achieve the requirements using different approaches and at lessened cost. Because firms can choose ways to comply with regulatory goals—by cutting emissions, buying offsets or some combination—incentives develop to reduce costs while achieving the goal of reducing total emissions within the regulated area. This approach has been more effective than the rigid attempts to regulate emissions as previously practiced.

Most observers believe regulatory schemes for dealing with carbon emissions in the near future are as inevitable as the Clean Air Act was for reducing atmospheric sulfur. Corporations in the United States are voluntarily joining up in efforts to trade carbon and reduce its emissions despite a current lack of political leadership at the federal level. In addition, although there is no clear federal policy, many states, including Pennsylvania, are advancing strategies for dealing with greenhouse gases and energy issues.

Carbon as a commodity

Carbon credits are the heart of a cap-and-trade approach for reducing carbon dioxide emissions. By offering a way to quantify carbon sequestered from the atmosphere, carbon credits gain a monetary value to offset a given amount of carbon dioxide releases. Whether through cap-and-trade, or through other policies that incentivize reductions in greenhouse gas emissions, being able to scientifically document the impact of practices which pull carbon out of the atmosphere will increase confidence in offset schemes in general.

For instance, a coal-fired electrical generation plant can meet its greenhouse gas reduction requirements by paying another business to make the amount of emission reduction they need, but cannot do immediately or as practically. This is particularly useful when the emission reduction is urgently needed and the large capital investment needed for a change at the plant site is not feasible.

Another example would be a business in a highly industrialized country, setting up forest development and preservation in a developing country where costs are relatively lower. In this scheme a market is created where businesses in need of carbon credits can buy them on a free and open market from legitimate approved sellers. Carbon credits are measured on the acquired right to emit one ton of carbon dioxide which is equivalent to burning about 600 pounds of carbon. Cap-and-trade works best when the results of a release are generalized, as in climate change. Other mechanisms are needed to effect improvements when emissions have a negative local impact that will not be mitigated by an offset elsewhere.

Agriculture as a carbon sink

Agriculture is a major potential seller of carbon credits. Plants serve as a sink, or reservoir, of carbon dioxide and the amount of soil carbon in organic matter is about two times that of the total atmospheric carbon as carbon dioxide.

The National Farmers Union (NFU) is aggregating carbon credits from farm acreage to be traded on the Chicago Climate Exchange www.chicagoclimatex.com. On the NFU website, rates for different regions of the country are shown.

Another exchange exists in Europe for the same purpose. No-till crop production can add about 300 pounds of carbon per acre each year.

Pennsylvania farmers are already engaging in practices that could be factored into a carbon credit program. Livestock farmers who are converting manure to renewable energy through biodigesters can aggregate carbon credits. The application of organic materials to the soil and no-till crop production can also be sources of carbon sequestration. Farmers with wind access could make carbon credits available through wind farm development.

The same soil at 1% (left) and 5% (right) soil carbon

In our work here at The Rodale Institute in Berks County, we have shown that growing winter crop covers is even more effective than no-till alone in increasing soil carbon. Cover crops have shown two to four times the values cited by the NFU. This suggests that our first attempts at carbon crediting are just scratching the surface. For carbon credits to be most effective, greater effort will be needed in their identification and verification so the benefit of local, regional and national farmers can be maximized.

Measuring soil carbon change

One of the biggest problems of assigning carbon credits is dealing with the inherent variability of natural field soil. We have approached this issue by taking many measurements for the 27 years that we have been tracking soil carbon. A rapid, precise and cost-effective means of carbon measurement will need to be developed in order to be able to credit farmers for their beneficial inputs in improving both our air and soil.

No Till, Biologically Based Production, and Compost Work Together to Increase Carbon Sequestration

Pennsylvania government officials have been trying to find economic opportunities in our current environmental challenges, including global warming. Since 2003, the secretaries of agriculture and environmental protection, Dennis Wolff and Kathleen McGinty, respectively, have sought to work with the Rodale Institute to better understand agricultural carbon sequestration and its potential to help the state meet its carbon emission goals. Validating new technology that will give farmers accurate measurements of carbon levels in their fields will help to implement offset programs in the Commonwealth and beyond.

To read more about state-funded research scheduled to commence in early 2008 at The Rodale Institute on new soil-testing technology that could make assessment of soil carbon levels much quicker, more practical and less expensive, click here.