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Global Warming Potentials The concept of a global warming potential (GWP) was developed to compare the ability of each greenhouse gas to trap heat in the atmosphere relative to another gas. The definition of a GWP for a particular greenhouse gas is the ratio of heat trapped by one unit mass of the greenhouse gas to that of one unit mass of CO2 over a specified time period. As part of its scientific assessments of climate change, the Intergovernmental
Panel on Climate Change (IPCC) has published reference values for
GWPs of several greenhouse gases. While the most current estimates
for GWPs are listed in the IPCC's Third Assessment Report (TAR),
EPA analyses use the 100-year GWPs listed in the IPCC's Second Assessment
Report (SAR) to be consistent with the international standards under
the United Nations Framework Convention on Climate Change (UNFCCC)
(IPCC, 1996 |
Global average atmospheric concentrations of N2O have increased
from about 270 parts per billion by volume (ppbv) in 1750 to 314 ppbv
in 1998, which equates to a 16% increase for the period. In the last two
decades, atmospheric concentrations of N2O continue to increase
at a rate of 0.25% per year. There has been significant multi-year variance
in the observed growth of N2O concentrations, and the reasons for these trends are not yet fully understood (IPCC, 2001b).
http://www.ghgonline.org/humaninfluencebig.htm
The US Global Change Research Program provides access points
to atmospheric measurement data related to nitrous oxide, as well as studies
of national and world nitrous oxide emissions.
The Carbon Dioxide Information Analysis
Center (CDIAC) also provides
access points to atmospheric measurement data related to nitrous oxide.
CDIAC's data holdings include records of the concentrations of carbon dioxide
and other radiatively active gases in the atmosphere and the role of the
terrestrial biosphere and the oceans in the life cycles of greenhouse
gases.
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