Model estimates of climate change impact on the vegetation cover and atmospheric carbon sink

The vegetation cover of terrestrial ecosystems plays an important role in the regulation of energy and mass exchange in the atmosphere-land surface system. In particular, plants actively absorb atmospheric carbon dioxide, thereby reducing the greenhouse effect. An important quantitative characteristic of the vegetation cover is its net primary production. Changes in the terrestrial net primary production under possible climate changes in the 21 st century are estimated. The computations are based on the dependence of net primary production on the surface radiation balance and evaporation. This dependence is derived using the relationship between the thermal conditions (annual total of effective daily mean surface temperature) and the radiation balance. Possible changes in the net primary production over Russia under a I degreesC increase in the annual mean global surface temperature are estimated by using the atmosphere-ocean general circulation models ECHAM4/OPYC3 and HadCM3 and the intermediate-complexity IAP RAS climate model for anthropogenic scenarios of greenhouse gas changes. The results obtained are used to estimate the atmospheric carbon sink associated with changes in the vegetation cover.