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Global deforestation: contribution to atmospheric carbon dioxide
Science (New York, N.Y.)
|December 9, 1983
Summary
Deforestation significantly impacts atmospheric carbon dioxide levels, releasing more carbon than fossil fuels until 1960. This study highlights deforestation as the primary biotic driver, with implications for climate change mitigation strategies.
Area of Science:
- Environmental Science
- Atmospheric Chemistry
- Ecology
Background:
- Terrestrial biota play a crucial role in atmospheric carbon dioxide (CO2) regulation.
- Historical data indicate significant carbon release from land-use changes, particularly deforestation.
Purpose of the Study:
- To quantify the net release of carbon from forest clearing between 1860 and 1980.
- To assess the relative contribution of biotic sources versus fossil fuels to atmospheric CO2.
- To evaluate the impact of deforestation on the airborne fraction of CO2.
Main Methods:
- Analysis of historical data on forest clearing and carbon release.
- Comparison of carbon release from biota and soils with fossil fuel emissions.
- Modeling of future biotic carbon release based on population growth.
Main Results:
- Global net carbon release from forest clearing (1860-1980) estimated at 135-228 x 10^15 grams.
- In 1980, deforestation accounted for nearly 80% of the 1.8-4.7 x 10^15 grams of carbon released.
- Biotic carbon release exceeded fossil fuel release until approximately 1960.
- The airborne fraction of total carbon release in 1980 was likely between 22-43%, not the commonly assumed 50% of fossil fuel release.
Conclusions:
- Deforestation is the dominant biotic factor influencing atmospheric CO2, contrary to theories of increased forest carbon storage offsetting releases.
- Projected biotic carbon release may reach 9 x 10^15 grams annually before forest exhaustion.
- Opportunities for limiting atmospheric CO2 accumulation through fossil fuel reduction and forest management may be underestimated.
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