Policy Implications of Greenhouse Warming Mitigation, Adaptation, and the Science Base (1992) / Chapter Skim
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11 Emission Rates and Concentrations Of Greenhouse Gases
11 Emission Rates and Concentrations Of Greenhouse Gases
Pages 91-99
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From page 91... ...
This enhancement of the greenhouse effect is called "greenhouse warming." Table 11.1 presents key attributes of the principal greenhouse gases deriving, in part or entirely, from human activities. CARBON DIOXIDE The increase from 280 ppmv (parts per million by volume)
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From page 92... ...
The 1990 total of emissions resulting from other human activities, even with the present rate of tropical deforestation, is about one-quarter the rate from burning fossil fuels alone.
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From page 93... ...
, nor are there as yet any observations to suggest that it might have become incorporated into the soil and/or biomass of the continents. Although there are substantial uncertainties in our understanding of the components of the carbon cycle, the atmospheric concentration of CO2 has been steadily increasing because of human activities2 in a manner that can be described by using a simple empirical relationship; e.g., increment in atmospheric CO2 at time t = 60% of accumulated fossil fuel emissions.
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From page 94... ...
The principal phenomena involved include biological processes in natural wetlands and rice paddies, burning of plant material in tropical and subtropical regions, consumption of biomass by termites, anaerobic decay of organic waste in landfills, and ventilation of coal mines. Additional sources include enteric fermentation by ruminant animals, leakage from natural gas pipelines, and venting from oil and gas wells.
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From page 95... ...
Future climatic changes could thus significantly affect the fluxes of CH4 from both natural wetlands and rice paddies. A highly uncertain but potentially large source of CH4 is the methane hydrates stored in permafrost sediments, CH4 trapped in permafrost, and decomposable organic matter frozen in the permafrost (Cicerone and Oremland, 1988~.
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From page 96... ...
The oceans also are a significant, although probably not dominant, source of N2O (McElroy and Wofsy, 19861. An accurate determination of the global annual ocean flux is difficult because of uncertainties associated with quantifying the gas exchange coefficient and because the partial pressure of N2O in the surface waters varies considerably, ranging from being supersaturated by up to 40 percent In upwelling regions to being undersaturated by a few percent In areas around Antarctica and in upwelling
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From page 97... ...
2. That human activities are causing the increasing atmospheric concentration of CO2 is known from carbon isotope studies.
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From page 98... ...
Journal of Geophysical Research 92:3098-3104. Intergovernmental Panel on Climate Change.
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From page 99... ...
1991. Primer on Greenhouse Gases.
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