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April 30, 2007
NASA MODELS SHOW TREES CAN SLOW
INCREASE OF ATMOSPHERIC CARBON
Converting
marginal agricultural land to forests may help slow the increase of
carbon in
the atmosphere, according to model-based results obtained by NASA
scientists
using space-based Earth observations and a state-of-the-art ecosystem
model.
Researchers
found that on a national basis, converting marginal agricultural lands
into
forests has the potential to remove hundreds of millions of tons of
carbon
dioxide from the atmosphere every year. This conversion, known as
afforestation,
could be used to partially off-set carbon emissions produced by burning
fossil
fuels.
“In
this
study, we primarily wanted to know how much atmospheric carbon dioxide
can be
absorbed by plant growth over the next 20 to 30 years, if 25 percent or
less of
the Unites States croplands and rangelands was planted with native tree
species,”
said Christopher Potter, lead author of the paper in Climatic Change,
published
by Springer Science+Business Media, and a scientist from NASA Ames
Research
Center, in California's Silicon Valley. “Our findings showed
that at least
one-fifth of annual fossil fuel emission of carbon in the United States
can be offset by planting new forests,” added Potter.
Using plants and soil to store atmospheric carbon dioxide could become
part of
our country’s enhanced land use management. Generalized
global estimates of
stored carbon in afforested areas vary between temperate and tropical
regions,
but range as high as 4.5 billion tons of carbon per year, say
scientists. These
estimates are from model results, not actual measurements, and many
questions,
scientific and economic, must be answered before such land use
practices are
adopted.
Researchers collected ‘greenness’ data from the
Advanced Very High Resolution
Radiometer (AVHRR) sensor on the NOAA Polar Operational Environmental
Satellite
(POES) and entered it into the NASA-Carnegie, Ames, Stanford
Approach (CASA) carbon model
at 8-kilometers' spatial resolution. The model generated three
different
national maps that showed estimates of the amount of carbon absorbed by
plants
growing in current forests, croplands and rangelands.
When the research was analyzed, the top five states identified as
having a high
carbon storage potential by converting croplands to newly developed
forests
were Texas, Minnesota,
Iowa, Illinois
and Missouri.
The top five states with potential for converting rangelands or
pastures were Texas,
California, Montana, New
Mexico and Colorado.
Research suggested that the southeast region of the United States
has the most
favorable conditions for afforestation due to its subtropical climate.
In
addition, model results suggested that large areas of croplands in South Dakota, Minnesota
and Wisconsin
showed potential for carbon management and shouldn’t be
underestimated.
Past studies show that managed land use practices can be very
productive in
removing carbon from the air, but variability in forest growth
conditions
across diverse climate, soil, water and elevation zones make it
difficult to
predict outcomes. “If rainfall patterns change, for whatever
reason, the risk
of losing plants can go up in drought-stricken areas,” noted
Potter.
This work was made possible through funding by NASA as part of the
long-term
USDA Northern Global Change Research Program, which is dedicated to
understanding how human-induced and natural changes affect our global
environment.
These and related studies appeared in the Springer Science+Business
Media
issues of Climatic Change, 2007.
For
more information and images,
visit:
http://www.nasa.gov/vision/earth/environment/afforestation.html
##
Contact:
Ruth Marlaire
NASA Ames
Research Center
650-604-4709
This text is
derived from:
http://www.nasa.gov/vision/earth/environment/afforestation.html
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