We investigated the impact of GCM-projected climate change on dryland crop rotations of wheat-fallow and wheat-corn-fallow in the Central Great Plains (Akron in Colorado, USA) using the CERES 4.0 crop modules in RZWQM2. The climate change scenarios for $CO_2$, temperature, and precipitation were produced by 22 GCM projections for Colorado based on the A1B scenario. The climate change for years 2050 and 2075 was super-imposed on measured 30-year-baseline climate data (1989-2008). For all the cropping rotations and projection years, simulated yields of wheat and corn decreased significantly (P < 0.05) with increasing temperatures. The yield declines due to the elevated temperatures should be attributable to the shortening of crop maturity duration and concurrent decreases in soil water and evapotranspiration. The model was also projected to decrease crop yields for the combined climate change scenarios of $CO_2$, temperature, and precipitation in the dryland cropping rotations.