Excerpt
Reducing anthropogenic greenhouse gas (GHG) emissions is the greatest environmental challenge facing society over the coming decades (NAS 2005). Although the largest global source of emission stems from the use of fossil fuels, land use, including agriculture, is the second greatest contributor to increasing GHG concentrations in the atmosphere, accounting for about 30% of total net emissions (IPCC 2007). The majority of these land use emissions are associated with deforestation and land conversion, mainly in the tropics; however, in the United States, agriculture contributes around 7% of total emissions (EPA 2007). The three main GHGs of concern—carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)—are all emitted through various agricultural activities, with the CH4 and N2O dominating agricultural emissions in the United States. However, agriculture has the capacity to not only significantly reduce its own emissions, but also to offset CO2 emissions from other sectors of the economy via carbon sequestration (CAST 2004; Paustian et al. 2006). By employing practices that increase organic matter content (about half of which is carbon) of soils, it is estimated that as much as 50 to 200 million t C per year of carbon offsets could be produced by US agriculture (Lal et al.…
Footnotes
Keith Paustian is a professor in the Department of Soil and Crop Sciences and the Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado. John Brenner is a natural resources consultant for the USDA Natural Resources Conservation Service, Lakewood, Colorado. Mark Easter is a research associate, Kendrick Killian is a research associate, and Stephen Ogle is a research scientist at the Natural Resource Ecology Laboratory, Colorado State University. Carolyn Olson is a national leader for climate change for the USDA Natural Resources Conservation Service, Washington, DC. Jill Schuler is a GIS specialist/programmer for the USDA Natural Resources Conservation Service, Fort Collins, Colorado. Roel Vining is on the National Air Quality Team, USDA Natural Resources Conservation Service, Portland, Oregon. Steve Williams is a research associate at the Natural Resource Ecology Laboratory, Colorado State University.
- © 2009 by the Soil and Water Conservation Society
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