Revised estimates of atmospheric CO/sub 2/ variations based on the tree ring /sup 13/C record
The composite mean /sup 13/C record for the Northern Hemisphere was revised. The overall decrease of delta /sup 13/C from 1800 to 1980 was estimated to be about -1.5/sup 0///sub 00/, which is 0.5/sup 0///sub 00/ less than the previous estimate. Therefore, the contribution of /sup 13/C-depleted CO/sub 2/ to the atmosphere from the forest and soil source was reevaluated, using the modified box-diffusion ocean model and Freyer's revised /sup 13/C record. On the basis of the assumption that this revised tree ring /sup 13/C record represents changes in the /sup 13/C//sup 12/C ratio induced in atmospheric CO/sub 2/ due to deforestation and soil manipulation and combustion of fossil fuels, the following results are obtained: (1) the magnitude of the integrated CO/sub 2/ release from the terrestrial biosphere since 1800 is about 90% of that from fossil fuel; (2) over the two-decade period covered by the Mauna Loa atmospheric CO/sub 2/ record, the input from the forest plus soil source is about 15% of that from fossil fuels; (3) the /sup 13/C//sup 12/C trend over the last two decades has been dominated by the input of fossil fuel CO/sub 2/; and (4) the pre-1850 atmospheric CO/sub 2/ content is estimated to be about 266 x 10/sup -6/ atm. 15 references, 5 figures, 1 table.
- Research Organization:
- Oak Ridge National Lab., TN (USA); Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6358597
- Report Number(s):
- CONF-831048-5; ON: DE85005273
- Resource Relation:
- Conference: Global carbon cycle - analysis of the natural cycle and implications of anthropogenic alterations for the next century, Knoxville, TN, USA, 31 Oct 1983
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON DIOXIDE
ECOLOGICAL CONCENTRATION
TREE RINGS
ISOTOPE RATIO
CARBON 12
CARBON 13
COMBUSTION PRODUCTS
DEFORESTATION
FOSSIL FUELS
GLOBAL ASPECTS
NORTHERN HEMISPHERE
POLLUTION SOURCES
SOILS
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON OXIDES
CHALCOGENIDES
EARTH PLANET
ENERGY SOURCES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FUELS
ISOTOPES
LIGHT NUCLEI
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PLANETS
STABLE ISOTOPES
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)
510200 - Environment
Terrestrial- Chemicals Monitoring & Transport- (-1989)