We study the consequences of multiplicative temperature noise (MTN) on the kinetics of the reaction CO + O-2 --> CO2 on an Ir(111) single-crystal surface. Without applied MTN, the CO2 kinetics exhibits bistability and hysteresis, apparently through low and high reactivity branches that can be accessed by proper variation of the O-2/CO ratio in the feed gas. In the theoretical description of the kinetics the hysteresis in the CO2 rate R as a function of the CO fraction Y in the total reactant input gas flux enters through nonlinearity of the oxygen sticking probability as a function of the CO and O coverages on the surface. We measured R(Y, T,DeltaT) in the Y range 0 to 0.3, for sample temperatures T between 400 K and 600 K, and DeltaT as Gaussian noise components imposed on T with half widths between 0.1 K and 50 K. We demonstrate experimentally as well as theoretically that the noise imposed on T affects the CO2 rate via the rate determining step, CO desorption at and above 450 K and the CO + O reaction at 420 K. Therefore, at 500 K, the long transients for the approach of equilibrium rates on the high and low reactivity branches are only affected by temperature noise if the CO desorption step is significant.