February 28, 2007
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A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 6, NUMBER 5, MAY 1993
section: "Evolution of Atmospheres," Science, 259(5097),
Feb. 12, 1993. Contains the following research reviews, as well
as several perspective articles.
"The Global Carbon Dioxide Budget," E.T. Sundquist
(U.S. Geol. Surv., Quissett Campus, Woods Hole MA 02543),
934-941. Although the increase in atmospheric CO2
during the last deglaciation was comparable in magnitude to the
recent historical increase, mechanisms differ for the two
intervals. For instance, the modern oceans are a rapid net CO2
sink, while they were a gradual source during the deglaciation.
Unidentified terrestrial CO2 sinks are important
uncertainties in both the deglacial and recent CO2
budgets; the deglacial budget is inadequately addressed by
current models used to forecast future atmospheric CO2
"The Ice Record of Greenhouse Gases," D. Raynaud
(Lab. Glac. & Geophys. de l'Environ., BP 96, F-38402
St.-Martin-d'Heres Cedex, France), J. Jouzel et al., 926-934. The
best-documented trace-gas records from polar ice are for CO2
and CH4. Measurements corresponding to the industrial
period document the recent changes in growth rate, and the
variability observed over the last 1000 years constrains the
possible feedbacks of a climate change on the trace gases under
similar conditions as today's. Other characteristics of the ice
record suggest that greenhouse gases are important in amplifying
the initial orbital forcing of Earth's climate, and help to
assess the feedbacks on the biogeochemical cycles in a climate
system in which the components are changing at different rates.
"Earth's Early Atmosphere," J.F. Kasting (Dept.
Geosci., Pennsylvania State Univ., Univ. Pk. PA 16802), 920-926.
"Atmospheric Evolution of the Terrestrial Planets,"
D.M. Hunten (Lunar & Planet. Lab., Univ. Arizona, Tuscon AZ
"Global Warming from Chlorofluorocarbons and Their
Alternatives: Time Scales of Chemistry and Climate," M.K.W.
Ko (Atmos. & Environ. Res. Inc., 840 Memorial Dr., Cambridge
MA 02139), N.D. Sze, G. Molnar, Atmos. Environ., 27A(4),
581-587, Mar. 1993.
Applies a simple model to illustrate a method for determining
the time variations of the radiative forcing and temperature
changes attributable to the direct greenhouse effect from
potential emissions of halocarbons. Despite uncertainties
inherent in the analysis, it illustrates an important aspect of
the greenhouse warming issue beyond what is provided by various
greenhouse warming indices. Calculations show that the warming
due to halocarbons will correspond to 4-10% of the total expected
greenhouse warming in the year 2100. However, uncontrolled growth
of substitutes could cause an eight-fold increase in halocarbon
production and a doubling of the halocarbon contribution by then.
"Large-Scale Dynamics and Global Warming," I.M. Held
(GFDL, Princeton Univ., POB 308, Princeton NJ 08542), Bull.
Amer. Meteor. Soc., 74(2), 228-241, Feb. 1993.
This review of a variety of issues in large-scale atmospheric
and oceanic dynamics concludes that we cannot expect a
theoretical (necessarily computational) approach to climate, in
isolation, to yield a totally convincing prediction of climatic
sensitivity in the near future.
"Using a Closed Ecological System to Study Earth's
Biosphere: Initial Results from Biosphere 2," M. Nelson
(Space Biosphere Ventures, Oracle AZ 85623), T.L. Burgess et al., BioScience, 43(4),
225-236, Apr. 1993.
Biosphere 2 has operated successfully since September 1991 as
a closed microbiosphere including humans, maintaining the overall
health of its diversity of internal ecosystems and a large
proportion of its species. Biogeochemical cycles are operating,
at least on the short term, with strong daily and seasonal fluxes
of atmospheric CO2, although oxygen concentration is
declining. Overall system biomass continues to increase, with
woodland canopies rapidly developing in rainforest, savannah, and
marsh. Although there are, as yet, no other natural biospheres
known for comparison to Earth, synthetic biospheres open
prospects for comparative biospherics and better understanding of
the Earth system. (See related item in Research News.)
"Velocity Structure of a Gas Hydrate Reflector," S.C.
Singh (Bullard Labs., Madingley Rd., Cambridge CB3 0EZ, UK), T.A.
Minshull, G.D. Spence, Science, 260(5105), 204-207,
Apr. 9, 1993.
Presents a method for measuring the amount of methane trapped
beneath methane hydrate layers along continental margins, using
seismic reflection profiles. Results from a site of the Ocean
Drilling Program suggest that methane hydrate and the underlying
gas represent a large global reservoir of methane, which may have
economic importance and may influence global climate.
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