On Apr 23, 7:36 pm, Cato



wrote:http://www.sciencemag.org/cgi/conten.../306/5702/1686

The scientific consensus is clearly expressed in the reports of the
Intergovernmental Panel on Climate Change (IPCC). Created in 1988 by
the World Meteorological Organization and the United Nations
Environmental Programme, IPCC's purpose is to evaluate the state of
climate science as a basis for informed policy action, primarily on
the basis of peer-reviewed and published scientific literature (3). In
its most recent assessment, IPCC states unequivocally that

the consensus of scientific opinion is that Earth's climate is being
affected by human activities: "Human activities ... are modifying the
concentration of atmospheric constituents ... that absorb or scatter
radiant energy. ... [M]ost of the observed warming over the last 50
years is likely to have been due to the increase in greenhouse gas
concentrations" [p. 21 in (4)].

IPCC is not alone in its conclusions. In recent years, all major
scientific bodies in the United States whose members' expertise bears
directly on the matter have issued similar statements.

For example, the National Academy of Sciences report, Climate Change
Science: An Analysis of Some Key Questions, begins: "Greenhouse gases
are accumulating in Earth's atmosphere as a result of human
activities, causing surface air temperatures and subsurface ocean
temperatures to rise" [p. 1 in (5)]. The report explicitly asks
whether the IPCC assessment is a fair summary of professional
scientific thinking, and answers yes: "The IPCC's conclusion that most
of the observed warming of the last 50 years is likely to have been
due to the increase in greenhouse gas concentrations accurately
reflects the current thinking of the scientific community on this
issue" [p. 3 in (5)].

Others agree. The American Meteorological Society (6), the American
Geophysical Union (7), and the American Association for the
Advancement of Science (AAAS) all have issued statements in recent
years concluding that the evidence for human modification of climate
is compelling (8).