Iowa emits 2 percent of the United States’ greenhouse gas emissions, or 108 MtCO2e*. About three-quarters of Iowa’s GHGs are CO2, primarily emitted from electric generation, motor vehicle use, and industrial energy use. Agriculturally based emissions make up the other quarter of Iowa’s GHG: 11 percent is methane, emissions produced principally by the ruminant digestive processes of livestock; and 14 percent is nitrous oxide, emissions produced as a byproduct of nitrogen-based fertilizers. The fact that 88 percent of Iowa’s land is used for crop and livestock production explains why Iowa produces nearly 60 percent higher greenhouse gas emissions per capita than the national average.

Carbon Sequestration
Forests can either store (sequester) or emit CO2. It is difficult to measure this in units of carbon, but when forests are cleared or burned, CO2 is emitted into the air with the same result as any other source of greenhouse gases. “Sink” is the term used to describe when carbon sequestered by forests exceeds released carbon. Between 1990 and 2003 Iowa increased its sink by 59 percent.*

Land surveys in 1846 estimated Iowa’s forests covered 6.7 million acres. In 1974 that number was reduced to 1.5 million acres. In 1999 that number rose to 2.0 million acres. Today’s estimates are at 2.7 million acres.

*World Resources Institute, Washington D.C., http://www.wri.org/about/

To view the World Resources Institute Report Charting the Midwest: An Inventory and Analysis of Greenhouse Gas Emissions in America's Heartland go to:
www.iowacleanair.com/prof/ghg/ghg.html