Carbon dioxide added to the atmosphere from the burning of fossil fuels and cement production has several possible pathways in the global carbon cycle. Understanding these pathways is key to understanding how much will remain in the atmosphere, and for how long, to contribute to global warming. Takahashi (2004) summarizes recent articles by Sabine et al (2004) and Feely (2004) that review current accepted views on what happens to industrial (anthropogenic) carbon dioxide. Sabine points out that about half of the carbon dioxide emitted to the atmosphere is absorbed by the oceans. Reduction of vegetation coverage in the terrestrial biosphere since 1800 due to deforestation and other land conversion has reduced the capacity for biospheric uptake of excess atmospheric carbon dioxide. However this loss is balanced by an almost equal magnitude of increased biospheric absorption of carbon dioxide due to increased plant growth due to higher atmospheric CO2 levels. The Feely et al. (2204) report discusses the role of CaCO3 in transporting CO2 from the surface to ocean layers not having contact with the surface and hence the acidic level of deep layers of ocean water.
References
Feely, R. A., and Co-Authors, 2004: Impact of anthropogenic CO2 on
the CaCO3 system in the oceans. Science, 305, 362-367.
Sabine, C. L., and Co-Authors, 2004: The oceanic sink for anthropogenic
CO2. Science, 305, 367-371.
Takahashi, T., 2004: The fate of industrial carbon dioxide. Science,
305, 352-353.