Back in the late 1800s when John Wesley Powell was navigating the unknown Colorado River his agency, the US Geological Service, did vital work filling in many blank spaces on the map of the nation. One of the original federal science agencies, USGS, is doing a new mapping of vital importance to the 21st century. The agency is surveying the potential of natural ecosystems to absorb and store carbon released by human activities.
Ordered by Congress in the 2007 Energy Act to map carbon sequestration potential across the nation, USGS on December 5 announced results of the first regional survey. That was for the Great Plains. Scientists looked at lands and waters across the 2.17-million-square-kilometer region and found it stores around 7,500 terragrams of carbon. (A terragram equals one million metric tons. U.S. annual fossil fuel emissions are around 1,500 terragrams.) By 2050, carbon storage could grow to 9,665-10,228 terragrams. That represents annual storage growth of 48-61 terragrams.
“This is truly groundbreaking research that, for the first time, takes a landscape-level look at how our lands naturally store carbon and explores how we can encourage this capability in ways that enhance our stewardship of natural resources,” said Deputy Secretary of the Interior David J. Hayes. “Our landscapes are helping us to absorb carbon emissions that would otherwise contribute to atmospheric warming.
Added Hayes, “This report will give tools to the policymakers, land managers and the public to make sound decisions, such as whether to restore wetlands, harvest trees, develop agricultural lands, or consider no-till farming practices.”
The full national survey is slated for completion by 2013. Between now and then USGS will issue regional studies covering the west, east, Alaska and Hawaii.
Agricultural lands are 42 percent of the Great Plains and account for 47 percent of 2050 carbon storage. Grass and shrub lands cover 48 percent but take up only 29 percent of 2050 carbon. Forests at five percent of the plains hold 20 percent of 2050 carbon. The remainder is in wetlands and other lands. The greater level of farm lands storage is due to favorable conditions of fertility and climate which lead to high carbon storage. Increased forest carbon storage is also projected due to fertilization from increased atmospheric carbon and low cutting rates.
Crop lands are projected to cover an additional 1.4-9.2 percent of the total region by 2050. Carbon releases from converting grass/shrub lands and forests could reduce the overall amount of carbon sequestered by 26-157 terragrams by 2050. The study suggests increased conservation of natural ecosystems to build carbon storage.