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 3, NUMBER 10, OCTOBER 1990
GLOBAL CO2 CYCLES
"The Sensitivity of Terrestrial Carbon Storage to Climate Change,"
K.C. Prentice (NASA Goddard Space Flight Ctr., 2880 Broadway, New York NY
10025), I.Y. Fung, Nature, 346(6279), 48-51, July 5, 1990.
Estimates the role of the terrestrial biosphere in controlling atmospheric
CO2 levels during climatic perturbations by simulating the global geographical
distribution of vegetation during the last glacial maximum, 18 kyr ago. Results
show that although the biosphere may have contributed to the decrease in
atmospheric CO2 of 80 ppm known to have occurred at 18 kyr, that does not seem
to have been a dominant factor. For simulations with twice present-day CO2
levels, strong negative feedbacks appear which remove 235 Gt of carbon from the
"El Niño and Atmospheric CO2," U. Siegenthaler (Phys.
Inst., Univ. Bern, Sidlerstr. 5, CH-3012, Bern, Switz.), Nature, 345(6273),
295-296, May 24, 1990. A comment on the apparent link between El Niño
Southern Oscillation events and fluctuations in atmospheric carbon dioxide
"Model Estimation of Excess CO2 Distribution in Biosphere Structure,"
V.F. Krapivin (Inst. Radio Eng. & Electronics, USSR Acad. Sci., Moscow
103907 USSR), L.P. Vilkova, Ecol. Model., 50(1-3), 57-58, Mar.
The model represents terrestrial biota by 30 types of ecosystems and uses a
two-layer ocean. The predicted contribution of the ocean and terrestrial biota
to excess CO2 absorption by the year 2000 will be 25% and 13%, respectively. Of
the total amount of carbon absorbed by the terrestrial biota by the year 2030,
temperate zone forests will absorb 28% of excess CO2 and tropical forests 49%.
"13C/12C of Atmospheric CO2 in the Amazon Basin: Forest and River
Sources," P. Quay (Sch. Oceanog., Univ. Washington, Seattle WA 98105), S.
King et al., J. Geophys. Res., 94(D15), 18,327-18,336, Dec. 20,
Concentrations and the delta 13C values of CO2 in the lower atmospheric
boundary layer were measured. Three major trends were observed: a diurnal cycle,
a vertical gradient, and different 13C composition for CO2 in air over the river
and in the forest. Results indicate that soil and plant respiration were the
primary sources of CO2 input to air in the forest, while degassing of CO2 from
the Amazon River is the likely source of CO2 input to air over the river.
"A Model to Estimate Carbon Dioxide Recycling in Forests Using
13C/12C Ratios and Concentrations of Ambient Carbon Dioxide," L. da S.L.
O'R. Sternberg, Agric. For. Meteor., 48(1-2), 163-173, Oct.
Investigates whether respired CO2 is largely refixed by photosynthesis of
forest vegetation, or released to the global atmospheric system. Uses a
steady-state model to predict the relationship between ambient forest CO2
concentrations and delta 13C values, as a function of the proportion of the
respired CO2 reabsorbed by photosynthesis. Comparisons of model predictions with
data collected in Panama show that about 7-8% of respired CO2 is recycled via
"Climatic Change and CaCO3 Preservation: An 800,000 Year Bathymetric
Reconstruction from the Central Equatorial Pacific Ocean," J.W. Farrell
(Dept. Geol. Sci., Brown Univ., Providence RI), W.L. Prell, Paleoceanog.,
4(4), 447-466, Aug. 1989. Investigated processes that promote the
cycling of carbon among several reservoirs and serve as important controls of
both oceanic carbon chemistry and atmospheric CO2 content over orbital time
scales (104 to 105 years).
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