February 28, 2007
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Global Climate Change Digest
A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 11, NUMBER 1-2, JANUARY-FEBRUARY 1998
OF GENERAL INTEREST
"Thermohaline Circulation, The Achilles Heel of Our Climate System:
Will Man-Made CO2 Upset the Current Balance?" W.S.
Broecker (Lamont-Doherty Earth Observ., Rte. 9W, Palisades NY 10964), Science,
278(5343), 1582-1588, Nov. 28, 1997.
Surveys extensive paleoclimatic evidence that changes in deep ocean
circulation are the key to rapid changes in climate, and discusses
implications for climate research and policy. Coupled ocean-atmosphere
models suggest that a large buildup of greenhouse gases might cause the
ocean's thermohaline to collapse, an outcome that would inflict sudden and
severe climatic stress on society. Until an improved next generation of
models comes along, we must take this prediction seriously.
Scientifically, this means greatly improving our knowledge of the deep
water formation process. As insurance, we must rapidly develop an energy
supply that does not load the atmosphere with CO2. Extraction
of hydrogen from fossil fuels (for use in fuel cells) and sequestration of
the remaining CO2 is a promising option.
"Keeping Watch on the Earth: An Integrated Global Observing Strategy,"
C.F. Kennel (Vice Chancellor, Univ. California at Los Angeles; e-mail:
firstname.lastname@example.org), P. Morel, G.J. Williams,Consequences,
3(2), 21-29, 1997. The text is also available on the World Wide
Web at: http://www.gcrio.org/CONSEQUENCES/introCON.html.
Although forty years have passed since the launch of the first orbiting
satellite, we have yet to put in place the integrated, international
observing system that is needed to track significant global changes, to
identify the marks of man on the natural environment, and to help separate
real concerns from false alarms. A permanent archive of what is changing
where, and by how much, would be invaluable information on climate and
many other aspects of the global environment. It would help our own and
future generations sort out human-induced perturbations from natural
"A Pervasive Millennial-Scale Cycle in North Atlantic Holocene and
Glacial Climates," G. Bond (Lamont-Doherty Earth Observ., Rte. 9W,
Palisades NY 10964; e-mail: email@example.com), W. Showers et
al.,Science, 278(5341), 1257-1266, Nov. 14, 1997.
Evidence from North Atlantic deep sea cores reveals abrupt climatic
shifts during the Holocene, the period since the last ice age
conventionally thought to have been quiescent. These and similar but
stronger fluctuations that occurred during the last ice age have a
cyclicity of 1470 (plus or minus 500) years. The Little Ice age appears to
be the most recent cold phase in the series of such cycles. However,
whether the climatic amelioration since the Little Ice Age marks the onset
of a warming phase of this natural cycle is unclear; brief warmings often
punctuated the cold phases of the millenial-scale fluctuations.
Two related items in Nature, 388(6645), Aug. 28, 1997:
"Influence of CO2 Emission Rates on the Stability of
the Thermohaline Circulation," T.F. Stocker (Phys. Inst., Univ. Bern,
Switz.; e-mail: firstname.lastname@example.org), A. Schmittner, 862-865. The
thermohaline circulation of the North Atlantic Ocean, which has a large
influence on climate and CO2 uptake, is sensitive to the level
of atmospheric CO2. This study uses a simple coupled
atmosphere-ocean model to show that the circulation also depends on the
rate of change of CO2. A modeled increase to 750 parts
per million by volume over the next 100 years, corresponding roughly to
today's growth rate, leads to a permanent shutdown of the thermohaline
circulation. But if CO2 increases more slowly, the circulation
merely slows down. This sensitivity to the rate of change of CO2
has potentially important implications for the choice of future CO2-emission
"Risk of Sea-Change in the Atlantic," S. Rahmstorf (Potsdam
Inst. for Clim. Impact Res. [PIK], POB 60 12 03, D-14412 Potsdam, Ger.;
e-mail: email@example.com), 825-826. A research comment on the
previous article, which serves as a reminder that swift action is needed
to reduce the risk of unwelcome climatic surprises.
"A 200-Year Record of Gale Frequency, Edinburgh, Scotland: Possible
Link with High-Magnitude Volcanic Eruptions," A.G. Dawson (Ctr.
Quaternary Sci., Coventry Univ., Coventry CV1 5FB, UK), K. Hickey et al.,The
Holocene, 7(3), 337-341, Sep. 1997.
Examination of what is believed to be the longest historical record of
gales in Europe shows three clear peaks in storminess that follow the
volcanic eruptions of Tambora (1815), Krakatoa (1833), and El Chichon
(1982). If this correlation has physical validity, the processes that link
large volcanic eruptions to storminess in the North Atlantic need to be
included in IPCC research that presently focuses on the effects of global
warming on storm frequency.
"Research Education," J. Hansen (NASA Goddard Inst. Space
Studies, 2880 Broadway, New York NY 10025; e-mail: firstname.lastname@example.org),
C. Harris et al.,J. Geophys. Res., 102(D22),
25,677-25,678, Nov. 27, 1997.
Describes a new program at NASA-Goddard that involves students and
educators working with scientists on problems at the top of their research
agenda. The students and faculty are responsible for producing research
results as well as educational materials that allow them to share the
research experience with their peers. Research teams have been formed on
several climate-related topics, and one team has coauthored a paper on
climatic fluctuations (published in this same issue of J. Geophys.
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