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
CLIMATE MECHANISMS AND FEEDBACKS
"Climate Change and the Global Atmospheric Electrical System,"
R.G. Harrison (Dept. Meteor., Univ. Reading, POB 243, Earley Gate, Reading
RG6 6BB, UK; e-mail: firstname.lastname@example.org),Atmos. Environ., 31(20),
3483-3484, Aug. 4, 1997.
Proposes briefly that in tropical regions, an increase in lightning can
be expected from an increase in temperature, a non-linear effect that
could have consequences for global ozone and even CO2.
"Responses of Atmospheric Methane Consumption by Soils to Global
Climate Change," G.M. King (Marine Ctr., Univ. Maine, Walpole ME
04573; e-mail: email@example.com),Global Change Biology, 3(4),
351-362, Aug. 1997.
Reviews a number of analyses indicating that atmospheric methane
consumption is generally reduced by human activities such as ammonium
deposition and changes in hydrology. Future trends in the soil methane
sink are likely to increase the accumulation of atmospheric methane.
"The Potential for Feedback Effects Induced by Global Warming on
Emissions of Nitrous Oxide by Soils," K.A. Smith (Inst. Ecol., Univ.
Edinburgh, Edinburgh EH9 3JG, UK; e-mail: firstname.lastname@example.org),Global
Change Biology, 3(4), 327-338, Aug. 1997.
A review concluding that models of global and regional trends give very
conflicting predictions of the direction and magnitude of climatic impacts
on nitrous oxide fluxes, but the prediction of a positive feedback seems
to be the more soundly based.
"Predicted Reduction in Basal Melt Rates of an Antarctic Ice Shelf in
a Warmer Climate," K.W. Nicholls (Brit. Antarctic Survey, High Cross,
Madingley Rd., Cambridge CB3 0ET, UK; e-mail: email@example.com),Nature,
388(6641), 460-461, July 31, 1997.
Uses measurements of temperature in a cavity beneath the Filchner-Ronne
Ice Shelf made during springtime warming as an analog for climate warming.
Concludes that moderate warming could lead to a basal thickening
of the shelf, perhaps increasing its longevity.
"How Dry Is the Tropical Free Troposphere? Implications for Global
Warming Theory," R.W. Spencer (NASA/Marshall Space Flight Ctr., ES41,
Huntsville Al 35806), W.D. Braswell,Bull. Amer. Meteor. Soc., 78(6),
1097-1106, June 1997.
The low humidity zones of the tropical free troposphere are poorly
measured by radiosondes, leading to substantial uncertainty in GCM
simulations. The latest satellite-based, microwave humidity sounder data
suggest even drier conditions than have been previously reported. This
underscores the importance of understanding how these low humidity levels
are controlled in order to tune and validate GCMs, and to predict the
magnitude of water vapor feedback and thus global warming.
"Variations in the Tropical Greenhouse Effect During El Nińo,"
B.J. Soden (NOAA/GFDL, POB 308, Princeton NJ 08542; e-mail: firstname.lastname@example.org),J.
Clim., 10(5), 1050-1055, May 1997.
Addresses the controversy over the role of water vapor as a feedback
mechanism of greenhouse warming. Results presented here provide
observational support for a positive water vapor feedback, and show that
GCMs are capable of simulating this effect.
"Inherently Unstable Climate Behavior Due to Weak Thermohaline Ocean
Circulation," E. Tziperman (Dept. Environ. Sci., Weizmann Inst. Sci.,
Rehovot 76100, Israel; e-mail: email@example.com),Nature,
386(6625), 592-595, Apr. 10, 1997.
Simulations of greenhouse warming often predict a weakening of the
thermohaline circulation (THC). This study uses a global coupled
ocean-atmosphere-ice GCM with realistic geography to show that there is a
wide range of weak mean states of the THC that cannot be stably sustained
by the climate system (and that would lead to climate fluctuations).
Two related items in Nature, 386(6626), Apr. 17, 1997:
"From the Labrador Sea to Global Change," B. Dickson (Ctr. for
Environ., Pakefield Rd., Lowestoft, Suffolk NR33 0HT, UK), 649-650.
Comments how studies like the following are providing an understanding of
the powerful changes that have occurred in the North Atlantic, and how
those changes may relate to global shifts in climate.
"Surprisingly Rapid Spreading of Newly Formed Intermediate Waters
Across the North Atlantic Ocean," A. Sy (Bundesamt für
Seeschiffahrt und Hydrographie, Bernhard-Nocht-Str. 78, D-20359 Hamburg,
Ger.; e-mail: firstname.lastname@example.org), M. Rhein et al., 675-679. Ocean
temperature, salinity and chlorofluorocarbon concentration data show that
water masses formed by deep convection in the Labrador Sea spread three to
four times faster than previously estimated, with associated consequences
for the North Atlantic thermohaline circulation.
Two related items in Nature, 385(6618), Feb. 20, 1997:
"Cool Tropical Punch of the Ice Ages," C. Charles (Scripps
Inst. Oceanog., La Jolla CA 92093; e-mail: email@example.com), 681-683.
Comments on the following article and other recent studies describing
observations of past tropical sea surface temperatures, which imply that
the tropical oceans are dynamically involved in glacial cycles. The nature
of tropical cooling during ice ages bears on the sensitivity of the
climate system to perturbations, including possible future anthropogenic
"Influence of Ocean Heat Transport on the Climate of the
Last Glacial Maximum, R.S. Webb (NOAA-NGDC Paleoclim. Prog., 325 Broadway,
Boulder CO 80303; e-mail: firstname.lastname@example.org), D.H. Rind et al., 695-699.
Climate simulations suggest (among other things) that climate sensitivity
for increased CO2 may be higher than the IPCC "best
"The Impact of Permafrost Thawing on the Carbon Dynamics of Tundra,"
C. Waelbroeck (Ctr. Faibles Radioactiv., Lab. mixte CNRS-CEA, 91198
Gif-sur-Yvette Cedex, France; e-mail: email@example.com), P. Monfray
et al.,Geophys. Res. Lett., 24(3), 229-232, Feb. 1, 1997.
A multi-component model shows that the tundra ecosystem's response to
thawing may be a long-lasting increase in carbon accumulation, following a
temporary increase in CO2 emissions.
"Polar Snow Cover Changes and Global Warming," H. Ye (Dept.
Geog., Univ. Delaware, Newark DE 19716), J.R. Mather,Intl. J.
Climatol., 17(2), 155-162, Feb. 1997.
Studies doubled CO2 temperature and precipitation
predictions from three GCMs for all land areas poleward of 60 latitude.
Total accumulation increases poleward of 60 latitude, with a major
increase in the Antarctic and a slight decrease in the Northern
"Principles for a Climate Regulation Mechanism during the Late
Phenerozoic Era, Based on Carbon Fixation in Peat-Forming Wetlands,"
L.G. Franzén (Dept. Phys. Geog., Göteborg Univ., S-413 81
Gothenburg, Sweden; e-mail: LARS@gig.gu.se), D. Chen, L.F. Klinger,Ambio,
25(7), 435-442, Nov. 1996.
Models the climate regulating effect of peat bogs, which act as carbon
sinks. With present levels of CO2, the model shows that the
initiation of a new ice age could already have been delayed roughly
700-1000 years. Scenarios with further increases in CO2 show a
much longer delay.
"Water Vapor and Cloud Feedback over the Tropical Oceans: Can We Use
ENSO as a Surrogate for Climate Change?" K.-M. Lau (NASA-Goddard,
Greenbelt MD 20771; e-mail: firstname.lastname@example.org), C.-H. Ho, M.-D.
Chou,Geophys. Res. Lett., 23(21), 2971-2974, Oct. 15,
Global climate model experiments show that regionally based interannual
variability should not be used to infer radiative feedback sensitivity for
climate change, unless proper corrections are made for the effect of large
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