Challenges of the 21st Century - Science For Environmental Protection: The Road Ahead - page 16

Increased demand for bioenergy, wind, and solar-power plants may also
place additional pressure on land resources. Beyond ethanol-based biofuels,
much of the bioenergy used in power generation is likely to come from forest
biomass through increased use of harvesting residues and (potentially) increased
harvesting. Forest ownership patterns have shifted over the last 20 years as a
result of the large-scale disaggregation of the forest-products industry. That shift
has increased land-use decisions that are based on maximizing shorter-term eco-
nomic returns rather than long-term production of forest products (USDA 2006).
When combined with more intensive use of forests to meet the demand for a
shifting basket of products (largely bioenergy), shifts in forest ownership may
have increasing effects on the environment. Thus, to pursue its environmental-
protection mission effectively in coming years, EPA will need to expand its ef-
forts to monitor and understand land-use changes.
Energy Choices
Energy choices in the United States—including bioenergy, conventional
and unconventional oil and gas production, coal, and nuclear power—all have
important implications for the environment through the effects of resource ex-
traction or production, fuel combustion, and waste discharge or disposal. The
April 2010 blowout of British Petroleum's Macondo deepwater oil well illus-
trated how devastating the unintended consequences of energy development can
be; the accident killed 11 workers and led to the largest oil spill in US history
and the closure of some fisheries in more than 80,000 square miles of the Gulf
of Mexico (NOAA 2012a). The rapid but less dramatic expansion of natural-gas
production across the United States has raised concerns about effects on local
water and air quality. There are also concerns about greenhouse-gas emissions
associated with methane leakage during production and transport, although natu-
ral gas is recognized as a fuel that inherently emits less greenhouse gas (about
half) than coal when combusted (Jaramillo et al. 2007). The comparative advan-
tages are lost at higher leak rates (that is, the rate at which methane, the primary
constituent of natural gas, is lost to the atmosphere during the production, trans-
portation, and use of natural gas) (Alvarez et al. 2012).
Another example is the production of ethanol for use as a biofuel, which
has increased rapidly in the last decade because of the desire for energy security
and renewable transportation fuels. In 2010, about 40% of US corn production
was used as feedstock for biofuel production (NRC 2011). Such agricultural and
energy choice practices can have negative environmental effects; increased pro-
duction of corn as an ethanol feedstock has resulted in increased nutrient runoff
and corresponding eutrophication of coastal waters, including the Gulf of Mex-
ico (NRC 2008, 2011). Given current water-use efficiencies, large quantities of
water are also required for irrigation and the intensification of agricultural prac-
tices can increase erosion (NRC 2008, 2011). Further research is required to
develop new perennial feedstocks that would require less tillage and have high