And it's also important to keep a longer term perspective when
considering Earth's "typical" state. The world we line in today is a
rather peculiar one, from the perspective of the last 500 million
years. The dominant state of Earth throughout this history is one
lacking glaciers altogether, with sea levels typically 50-100 m
higher, and in a deeply greenhouse climate/oceanographic
system. Consider that the majority of the US midcontinent is covered
in sedimentary rocks of marine origin. Unfortunately (for us),
humans did not evolve in such a world, and, until now, have never
needed to live in one. Note that I'm not arguing as a skeptic
against anthropogenic climate change--indeed, that the current
geological state is in opposition to a natural greenhouse state is
all the more worrisome that it's occurring, and at an exceedingly
fast rate geologically. But that it's important to be cognizant of
the rather unusual condition of our current earth on which we're
lucky enough to live.
Useful references:
Miller KG, Kominz MA, Browning JV, Wright JD, Mountain GS, Katz ME,
Sugarman PJ, Cramer BS, Christie-Blick N, Pekar SF. 2005. The
Phanerozoic record of global sea-level change. Science 310:1293-1298.
Stanley, S.M. 2009. Earth System History. 3nd ed. W.H. Freeman
and Co., New York.
Phil .
At 11:44 AM 5/24/2009, Paul E. Reyerson wrote:
I agree. There are many false statements. For example, there is strong
evidence that anthropogenic-induced climate change will lead to sea level
rise. See the recent article by Bamber et al in the May 15 issue of Science
and the references therein for more information. It is true that sea levels
are naturally higher now than in the last glacial period, but that certainly
doesn't mean they couldn't go higher.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Phil
Novack-Gottshall pnova...@westga.edu
Assistant Professor
Department of Geosciences
University of West Georgia
Carrollton, GA 30118-3100
Phone: 678-839-4061
Fax: 678-839-4071
http://www.westga.edu/~pnovackg
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