This work is devoted to the numerical study of characteristics of dielectric barrier discharge maintained in a coaxial reactor in atmospheric pressure CO2. The numerical model is based on the drift-diffusion theory of gas discharges, and takes into account the gas heating in a self-consistent manner. The effect of incorporating gas heating into the discharge properties, specifically, on CO2 decomposition, is investigated for wide range of amplitude and frequency of the applied voltage. Calculations revealed a significant effect of gas heating on CO2 conversion. Calculations with a constant (room) gas temperature led to a strong overestimation of CO2 conversion level.