ИСТИНА

The approach for long-term scenario projection of river runoff changes for Russian large river basins in the first third of XXI century caused by climate warming and social-economic changes is suggested. The approach utilizes a method for scenario estimation of runoff changes with ranging possible climate warming effects. This range is chosen by generalizing calculation results obtained by using an ensemble of global climate models within CMIP 3 and CMIP 5 experiments for two contrasting scenarios (A2/RCP 8.5 and B1/RCP 2.6) of globally averaged air temperature rises. The approach also utilizes a method for alternative scenario water consumption estimation as related to socio-economic changes. The obtained scenario estimates show that expected changes in the Volga and Don annual river runoff and its intra-annual distribution in the first third of this century can be relatively small, while changes in water use characteristics may be in some scenarios extremely negative especially in the Don river basin.