Affiliations: 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 | Morthern Forestry Center, Canadian Forest Service,
5320-122 Street, Edmonton,Alberta T6H 3S5, Canada
Note: [] Corresponding author
Abstract: 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.
Keywords: climatic variable, sensitivity experiment, soil respiration, statistical model
