| 1 | Simulating global soil-CO_2 flux and its response to climate change显示文摘It has been argued that increased soil respiration would become a major atmospheric source of CO\-2 in the event of global warming. The simple statistical models were developed based on a georeferenced database with 0 5°×0 5° longitude/latitude resolution to simulate global soil\|CO\-2 fluxes, to investigate climatic effects on these fluxes using sensitivity experiments, and to assess possible responses of soil\|CO\-2 fluxes to various climate change scenarios. The statistical models yield a value of 69 PgC/a of global soil\|CO\-2 fluxes for current condition. Sensitivity experiments confirm that the fluxes are responsive to changes in temperature, precipitation and actual evapotranspiration, but increases in temperature and actual evapotranspiration affect soil\|CO 2 fluxes more than increases in precipitation. Using climatic change projections from four global circulation models, each corresponding to an equilibrium doubling of CO 2, it can be found that the largest increases in soil\|CO 2 fluxes were associated with the boreal and tundra regions. The globally averaged soil\|CO 2 fluxes were estimated to increase by about 35% above current values, providing a positive feedback to the greenhouse effect. | PENG Chang\|hui 1* , Michael J. Apps\+2 (1 Ontario Forest Research Institute, Ministry of Natural Resources, 1235 Queen Street East, Sault Ste. Marie, ON P6A 2E5,Canada. E\|mail: pengc@gov.on.ca 2 Morthern Forestry Center, Canadian Forest Serv | 2000 | Journal of Environmental Sciences2000，12，3： | 2 |
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