Developing Greenhouse Gas Emissions Offsets By Reducing Nitrous Oxide (N2O) Emissions in Agricultural Crop Production: Experience Validating New GHG Emissions Offset Protocols.

Nitrous oxide (N₂O) is a significant greenhouse gas (GHG) that contributes to global climate change. Each ton of N₂O emitted to the atmosphere is equivalent to emitting approximately 300 metric tons of CO₂ (ton CO₂e) because of N₂O’s high Global Warming Impact (GWI). Consequently, GHG emission offset projects that reduce emissions of even small amounts of N₂O can have a disproportionately large effect on climate change. This sensitivity to small changes provides a strong impetus for including N₂O in the development of effective GHG mitigation strategies.

Nitrous oxide emissions reductions from crop production offers an approach that can generate large-scale, cost-effective GHG emissions offsets that could be implemented across broad geographic areas of the U.S. and internationally. Economic analysis of “economy-wide” legislative proposals have concluded that GHG emissions offsets are likely to play a key role in reducing the economic cost ($/ton CO₂e) of achieving GHG emissions reductions, and have identified the agricultural sector to provide a key source of potential domestic GHG offsets.

Since 2006, Michigan State University (MSU) has been collaborating with the Electric Power Research Institute (EPRI) on a research project to explore the potential to reduce N₂O emissions by improving nitrogen (N) management practices on croplands in the U.S. Between 2007 and 2009, MSU researchers conducted fundamental research on commercial farm fields and research plots in Michigan to improve the scientific understanding of N₂O emissions based on the amount of N fertilizer applied to corn.

Between 2010 and 2013, MSU researchers developed an N₂O Offsets Methodology that has been approved by the American Carbon Registry (ACR), and the Verified Carbon Standard (VCS) for use in their voluntary GHG emissions offsets programs. Major components of the MSU-EPRI Methodology also underpin the Nitrogen Management Project Protocol adopted by the Climate Action Reserve (CAR-NMPP).

The approval of the MSU-EPRI Methodology by these three primary voluntary offset standards organizations is expected to provide impetus for the California Air Resources Board (ARB), United States Department of Agriculture (USDA), and other organizations to adopt a similar approach for developing future compliance offset methodologies and programs to reduce N₂O emissions in agricultural crop production.

A small-scale pilot project that uses the MSU-EPRI Methodology also has been completed, and has been submitted to the ACR for verification and issuance of offset credits. Carbon offset credits generated by this Michigan-based, project are expected to be issued, sold and retired during 2013, and will to our knowledge represent the world’s first trade of offsets derived from agricultural N₂O emissions reductions.