The global carbon cycle and climate change: responses and feedbacks from below-ground systems.
According to most global climate models, a continued build-up of CO2 and other greenhouse gases will lead to significant changes in temperature and precipitation patterns over large parts of the Earth. Below-ground processes will strongly influence the response of the biosphere to climate change and are likely to contribute to positive or negative biospheric feedbacks to climate change. Current global carbon budgets suggest that as much as 2000 Pg of carbon exists in soil systems. There is considerable disagreement, however, over pool sizes and flux (e.g. CO2, CH4) for various ecosystems. An equilibrium analysis of changes in global below-ground carbon storage due to a doubled-CO2 climate suggests a range from a possible sink of 41 Pg to a possible source of 101 Pg. Components of the terrestrial biosphere could be managed to sequester or conserve carbon and mitigate accumulation of greenhouse gases in the atmosphere.
Dixon
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Environmental Research Laboratory, US Environmental Protection Agency, 200 SW 35th Street, Corvallis, Oregon 97333, USA.
Turner
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