US agriculture has much to offer as a participant in efforts to mitigate the buildup of GHGs in the atmosphere, and, in most cases, the adoption of practices that mitigate GHGs will provide additional environmental services and improved resource use efficiency on America's farms. Whether agriculture will reap the financial benefits possible as a provider of GHG offsets within the framework of a cap-and-trade market or other regulatory framework will depend to a large extenton the quantification, monitoring, andverification of these offsets.