You are here:
PLANETARY METABOLISM: UNDERSTANDING THE CARBON CYCLE
Citation:
III, B. AND B. Braswell, Jr. PLANETARY METABOLISM: UNDERSTANDING THE CARBON CYCLE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/458.
Description:
Biological systems are intimately involved in the transfers of energy and materials around our planet, affecting the geochemistry and other physical properties of the atmosphere, the land surface, ant the oceans and their sediments. ossil-fuel combustion, land use, and other human activities are, increasingly, disrupting these natural biogeochemical cycles and processes, with the potential for far-reaching consequences; for example, changes in atmospheric composition affecting the global heat balance. he carbon, nitrogen and sulfur cycles are of particular importance to the functioning of the biosphere, and are also closely linked to the physical climate system. ithin IGBP, the global-scale modeling effort is initially focused on the car-bon cycle: this is poorly understood--yet is critical to estimating future levels of carbon dioxide and other greenhouse gases, and their direct and indirect interactions with the biosphere. o assist in determining the factors that influence the atmospheric lifetime of carbon dioxide, the concept of a single half-life is applied to three simple ocean carbon-cycle models and a model of global terrestrial carbon cycling. e find significant differences due to the inclusion of the terrestrial model and the nature of the assumptions made about the possible terrestrial fertilization response: halflife estimates vary between 92 years (no allowance for terrestrial effects) to 27 years (with both terrestrial regrowth plus fertilization).