|
|
Printer-friendly
format
Download PDF version
Email this page
Is Carbon Sequestration in Agriculture Economically Feasible?
Comstock
|
Increased atmospheric concentrations of carbon dioxide and other “greenhouse” gases
have contributed to the gradual rise in global temperatures over
the last 50 years. Two options for reducing the amount of carbon
in the atmosphere are to increase the amount of land planted with
permanent grassland or forest vegetation and to reduce the frequency
or intensity of tillage operations. Either option would store—or
sequester—additional carbon on the affected lands. In February
2002, the White House announced a plan to reduce the growth of
U.S. greenhouse gas emissions, in part by developing incentives
for farm and forestland owners and operators to adopt land uses
and management practices that extract carbon from the air and sequester
it in soils and vegetation.
U.S. agricultural soils have lost, on average, about one-third of the carbon
they contained before wide-scale cultivation began in the 1800s. Soil science
studies suggest that changes in land use and land management practices could
increase the carbon content of crop and grazing land soils by 104-318 million
metric tons per year. Forestry studies suggest that afforestation of cropland
and pasture could add another 91-203 million metric tons per year.
While the U.S. farm sector’s technical potential to store carbon is
important to know, it is really the economic potential for storing carbon
that is most
directly relevant to policymakers. Using different incentive payment structures,
ERS researchers analyzed the economic feasibility of increasing carbon levels
in soils and vegetation by providing various levels of payments to convert
croplands and pasture to trees, shift cropland to permanent grasses, and/or
increase the
use of conservation tillage systems.
At payment levels below $10 per metric ton of additional permanently stored carbon,
landowners find it more cost-effective to adopt conservation tillage practices,
as compared with other changes to land use and management practices. At higher
payment levels, converting cropland to trees becomes more cost effective. For
payments equal to $125 per metric ton of additional permanently stored carbon,
farmer adoption of conservation tillage and afforestation of crop or grazing
land could yield 72-160 million metric tons of carbon, enough to offset 4-8 percent
of gross U.S. emissions of greenhouse gases in 2001. Converting cropland to grass
did not prove to be a cost-effective option at any payment level analyzed.
The economic potential, even at the $125-payment level, is much less than the
technical potential suggested by soil science and forestry studies because
activities that are technically feasible are not always economically feasible.
Furthermore,
the share of the technical potential that is economically feasible varies greatly
across activities because of the wide variation in the costs farmers would
incur in adopting different carbon-sequestering land uses and practices.
|
|
This article is drawn from...
|
|
Economics of Sequestering Carbon in the U.S. Agricultural Sector,
by Jan Lewandrowski, Mark Peters, Carol Jones, Robert House, Mark Sperow, Marlen
Eve, and Keith Paustian, TB-1909, USDA/ERS, April 2004.
|