Transportation's Role in Reducing U.S. Greenhouse Gas Emissions ...

Transportation's Role in Reducing U.S. Greenhouse Gas Emissions: Volume 1
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anywhere from 25 to 90 percent between the years 2000 and 2030, with CO2
emissions from energy use growing between 40 and 110 percent over the same
period.
According to the Intergovernmental Panel, “Warming of the climate system is
unequivocal, as is now evident from observations of increases in global average
air and ocean temperatures, widespread melting of snow and ice, and rising
global average sea level.” 19 The panel projects that global temperatures will rise
2-to-11.5°F by 2100, and global sea level will rise 7-to-23 inches (the range of
results represents uncertainty in both future anthropogenic emissions and
climate modeling). More recent research, including the effects of polar ice sheet
melting, suggest that sea levels could rise 3-to-4 feet by the end of this century. 20
The IPCC’s report also describes the anticipated consequences of climate change
along the range of potential temperature increases, showing severe impacts
above 2°C (3.6°F). According to the IPCC, global GHGs must be reduced to 50to-85
percent below year 2000 levels by 2050 to keep warming to 2.0-to-2.4°C
(3.6-to-4.3°F).
Changes in global temperature, and associated changes in weather patterns, have
a broad impact on ecosystems, food production, coastlines, human settlements,
health, and water supply. In North America, the impact of climate change is felt
as drought in areas of the West, because of the reduced mountain snowpack;
deteriorating forest health from the increased spread of pests, diseases, and
forest fires; changes in agricultural productivity; an increase in the frequency and
severity of heat waves, which create adverse health issues for people and
animals; and an increase in the risk of flooding in coastal communities.
According to USGCRP, widespread climate-related impacts are occurring now
and are expected to increase. However, the extent of climate change, and its
impacts, depends on the choices made today to mitigate human-caused
emissions of GHGs. 22
Climate change also impacts transportation systems. Rising sea levels and more
intense storms can cause increased flooding of coastal transportation facilities
such as roads, rail lines, airports, and ports. A DOT study of the central U.S.
19 IPCC Synthesis, 2007 (cited).
20 USGCRP, 2009 (cited).
21 Intergovernmental Panel on Climate Change (IPCC) (2007). Climate Change 2007:
Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Third
Assessment Report of the Intergovernmental Panel on Climate Change [Parry, Martin L.,
Canziani, Osvaldo F., Palutikof, Jean P., van der Linden, Paul J., and Hanson, Clair E.
(eds.)]. Cambridge University Press, Cambridge, United Kingdom.
22 U.S. Global Change Research Program (2009). Global Climate Change Impacts in the
United States. Thomas R. Karl, Jerry M. Melillo, and Thomas C. Peterson, (eds.).
Cambridge University Press, p.12.
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