New Science Estimates Carbon Storage Potential of U.S. Lands

USGS News Release, December 10, 2009

Nation's Forests and Soils Store Equivalent of 50 Years of U.S. CO2
Emissions

The first phase of a groundbreaking national assessment estimates that U.S.
forests and soils could remove additional quantities of carbon dioxide (CO2)
from the atmosphere as a means to mitigate climate change.

The lower 48 states in the U.S. hypothetically have the potential to store
an additional 3-7 billion metric tons of carbon in forests, if agricultural
lands were to be used for planting forests. This potential is equivalent to
2 to 4 years of America's current CO2 emissions from burning fossil fuels.

"Carbon pollution is putting our world-and our way of life-in peril," said
Secretary of the Interior Ken Salazar in a keynote speech at the global
conference on climate change in Copenhagen, Denmark. "By restoring
ecosystems and protecting certain areas from development, the U.S. can store
more carbon in ways that enhance our stewardship of land and natural
resources while reducing our contribution to global warming."

U.S. Geological Survey scientists also found that the conterminous U.S.
presently stores 73 billion metric tons of carbon in soils and 17 billion
metric tons in forests. This is equivalent to more than 50 years of
America's current CO2 emissions from burning fossil fuels. This shows the
need to protect existing carbon stores to prevent additional warming and
future harm to ecosystems.

America's forests and soils are currently insufficient in soaking up the
nation's accelerating pace of emissions. They currently absorb about 30
percent (0.5 billion metric tons of carbon) of the nation's fossil fuel
emissions per year (1.6 billion metric tons of carbon). Enhancing the carbon
storage capacity of America's and the world's ecosystems is an important
tool to reduce carbon emissions and help ecosystems adapt to changing
climate conditions.

"The tools the USGS is developing-and the technologies behind those
tools-will be of great use to communities around the world that are making
management decisions on carbon storage," said USGS Director Marcia McNutt.
"The USGS is conducting a national assessment of biologic carbon
sequestration, as well as an assessment of ecosystem carbon and greenhouse
gas fluxes, which will help determine how we can reduce atmospheric CO2
levels while preserving other ecological functions."

To determine how much more carbon could be stored in forests and soils, USGS
scientists analyzed maps that represent historical vegetation cover before
human alterations, as well as maps of vegetation that might occur if there
were no natural disturbances, such as fires, pests and drought. These maps
were compared to maps of current vegetation and carbon storage.

The next phase of this work will assess the additional amount of carbon
stored in Alaska's ecosystems, including its soils and forests. The USGS
plans to collaborate with U.S. Department of Agriculture and other agencies
to examine potential carbon storage in soils.

The USGS is conducting research on a number of other fronts related to
carbon sequestration. These efforts include evaluating the potential for
storing carbon dioxide in geologic formations below the Earth's surface,
potential release of greenhouse gases from Arctic soils and permafrost, and
mapping the distribution of rocks suitable for potential mineral
sequestration efforts.

For more information about this assessment, visit
http://pubs.usgs.gov/ofr/2009/1283.