Possible changes in the habitats of zonal phytocenoses for the plain territories of Russia under a 1 degrees C increase in the annual mean global surface temperature are estimated by simulation with the atmosphere-ocean general circulation models ECHAM4/OPYC3 and HadCM3 and the intermediate-complexity climate model of the Institute of Atmospheric Physics for anthropogenic scenarios of greenhouse gas changes. The response of the phytocenotic habitats to possible climate changes is estimated from the changes in net primary production for the considered climatic scenarios. The obtained data allowed us to recognize the zonal phytocenoses most sensitive to climate changes.