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 6, NUMBER 10, OCTOBER 1993
GLOBAL CARBON BUDGET
"Rainforest Burning and the Global Carbon Budget: Biomass,
Combustion Efficiency, and Charcoal Formation in the Brazilian
Amazon," P.M. Fearnside (Dept. Ecol., Nat. Inst. Res.
Amazon, CP 478, 69011-970, Manaus, Amazonas, Brazil), N. Leal
Jr., F.M. Fernandes, J. Geophys. Res., 98(D9),
16,733-16,743, Sep. 20, 1993.
Biomass present before and after burning was measured in
forest cleared for a cattle ranch. Only about 2.7% of the preburn
aboveground carbon stock was converted to charcoal, substantially
less than is generally assumed in global carbon models. The high
values for biomass found suggest the significant potential
contribution of forest burning to climate change from CO2
and trace gases.
"Atmospheric Carbon Dioxide and the Ocean," U.
Siegenthaler (Phys. Inst., Univ. Bern, 3012 Bern, Switz.), J.L.
Sarmiento, Nature, 365(6442), 119-125, Sep. 9,
Evaluates the various recent estimates of the carbon budget,
concluding that the ocean takes up about a third of the CO2
emissions arising from fossil-fuel use and tropical
deforestation. This implies that there is a "missing
sink" of carbon which may be located in the terrestrial
biosphere. Details research needed on the carbon cycle if we are
to predict future changes of atmospheric CO2.
items from Global Biogeochem. Cycles, 7(3), Sep.
"Carbon Remineralization in a North Florida Swamp Forest:
Effects of Water Level on the Pathways and Rates of Soil Organic
Matter Decomposition," J.D. Happell (Dept. Appl. Sci.,
Brookhaven Nat. Lab, Upton NY 11973), J.P. Chanton, 475-490.
Extensive measurements describe how water level controls CO2
and CH4 emissions from North Florida swamp forests.
Develops a carbon budget for the site under flooded and dry
"Can Climate Variability Contribute to the 'Missing' CO2
Sink?" A. Dai (Dept. Geol. Sci., Columbia Univ., 2880
Broadway, New York NY 10025), I.Y. Fung, 599-610. A study
involving empirical models and global temperature and
precipitation data shows that climatic variability could have
accounted for half the missing CO2 sink for the period
1950-1984. Climate variations have unequal impacts on biospheric
carbon fluxes, and caution is needed in generalizing in situ
observations to the globe.
"Is Carbon Accumulating in the Northern Temperate
Zone?" R.A. Houghton (Woods Hole Res. Ctr., POB 296, Woods
Hole MA 02543), 611-618. Based on recent studies showing an
accumulation of carbon in Northern Hemisphere temperate forests,
one might conclude that the missing carbon sink has been
explained. However, when the fate of wood previously removed from
these regrowing forests is considered, the imbalance remains, and
is apparently too large to be accommodated in aboveground
"Evaluation of the 13C Constraint on the Uptake of Fossil
Fuel CO2 by the Ocean," W.S. Broecker
(Lamont-Doherty Earth Observ., Palisades NY 10964), T.-H. Peng,
619-626. Examines this proposal by Quay et al. (1992) and finds
that the data base is too inaccurate to permit a distinction to
be made among the carbon budgets currently proposed by this
method. Tracer-verified ocean GCMs offer much better estimates
than those based on the 13C budget.
"Constraints on the Alkalinity and Circulation of Glacial
Circumpolar Deep Water from Benthic Foramniferal Barium,"
D.W. Lea (Dept. Geol. Sci., Univ. California, Santa Barbara CA
93106), 695-710. Redistribution of ocean alkalinity has been
suggested as a possible cause of glacial-to-interglacial CO2
change. This analysis concludes that such redistribution could
account for about a third of the observed p-CO2
Issue: "Ocean Carbon Cycle and Climate Change," Global
& Planetary Change, H.J.W. de Baar, E. Suess, Eds., 8(1-2),
July 1993 (Elsevier Sci. Publishers).
Contains a selection of eight papers presented at the
Interdisciplinary Union Symposium during the April 1993 meeting
of the European Union of Geosciences (Strasbourg). The papers
provide a mix of original research findings with overviews of the
topic, and deal with the carbon cycle on various time scales.
"Response of the Biosphere to the Changing Global
Environment: Evidence from Historic Record of Biotic
Metabolism," C.A.S. Hall (Coll. Environ. Sci. Forestry,
State Univ. N.Y., Syracuse NY 13210), World Resour. Rev., 5(2),
207-213, June 1993. (See Global Climate Change Digest,
items from Global Biogeochem. Cycles, 7(2), June
"Comparison of Carbon Dynamics in Tropical and Temperate
Soils Using Radiocarbon Measurements," S.E. Trumbore (Dept.
Geosci., Univ. California, Irvine CA 92717), 275-290. Based on
modeling the observed increase of 14C in organic matter pools
since atmospheric weapons testing ended, this analysis shows that
carbon cycle models, which treat soil carbon dynamics as a single
reservoir, underestimate the annual fluxes of organic matter,
especially in the tropics.
"CO2 and CH4 Dynamics of a Spahghum-Dominated
Peatland in West Virginia," J.B. Yavitt (Dept. Natural
Resour., Fernow Hall, Cornell Univ., Ithaca NY 14853), R.K.
Wieder, G.E. Lang, 259-274. Field measurements suggest that a
temperate climate imposed on northern peatlands could mobilize
stored carbon and increase CO2 and CH4
emission into the troposphere.
"Oceanic 13C/12C Observations: A New Window on Ocean CO2
Uptake," P.P. Tans (CMDL, NOAA, 325 Broadway, Boulder CO
80303), J.A. Berry, R.F. Keeling, 353-368. Develops equations for
the rate of change of carbon isotopic ratios in the atmosphere
and ocean in terms of d13C quantities, as a means of estimating
the fate of fossil fuel carbon. The isotopic ratio approach has
advantages but demands extremely high accuracy in the
from Nature, 363(6428), June 3, 1993:
"Heavy Carbon Dioxide," R.F. Keeling (Scripps Inst.
Oceanog., La Jolla CA 92093), 399-400. Discusses implications of
the following paper, which contributes to understanding the
behavior of oxygen isotopes in the atmosphere and eventually the
"missing carbon sink."
"Vegetation Effects on the Isotope Composition of Oxygen
in Atmospheric CO2," G.D. Farquhar (Plant
Environ. Biol. Group, Inst. Advanced Studies, Australian Nat.
Univ., GPO Box 475, Canberra, ACT 2601, Australia), J. Lloyd et
al., 439-443. Investigates how the fractionation of the oxygen
isotopes of CO2 that occurs in plants influences the
global distribution of the isotopes. Results provide an
explanation for the depletion of 18O in atmospheric CO2
at high northern latitudes.
New Optical Sensor for P-CO2 Measurements in
Sea Water," N. Lefèvre (Univ. Paris 7, Lab. Gèochim. des
Eaux, URA 196 et IPGP, F-75251 Paris Cedex 05, France), J.P.
Ciabrini et al., Marine Chem., 42(3-4), 189-198,
June 1993. The sensor can remain unattended on an ocean buoy for
a full year.
and reply on whether open ocean phytoplankton production has
remained constant since the industrial revolution, Nature, 362(6423),
795-796, Apr. 29, 1993.
Strategy for Estimating the Impact of CO2
Fertilization on Soil Carbon Storage," K. Harrison
(Lamont-Doherty Earth Observ., Palisades NY 10964), W. Broecker,
G. Bonani, Global Biogeochem. Cycles, 7(1), 69-80,
Mar. 1993. (See Global Climate Change Digest, Sep. 1993.)
"Winter Biotic Activity and Production of CO2 in
Siberian Soils: A Factor in the Greenhouse Effect," S.A.
Zimov (North-East Sci. Sta., Pacific Inst. Geog., Far East
Branch, Russian Acad Sci., Vladivostok 690022, Russia), J.
Geophys. Res., 98(D3), 5017-5023, Mar. 20, 1993.
Measurements made at 70?N in winter show that biological
activity at the bottom of the active layer above the permafrost
is sufficient to explain an observed winter maximum in
atmospheric CO2. Ecological and anthropogenic factors
may play a role in stimulating this emission.
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Index of Abbreviations