A gas sensor includes a plurality of sensing resistors that vary in resistance based on ambient temperature and the presence of certain gases, such as CO2 and H2O. The responses of each of the sensing resistors vary based on a base temperature of each of the sensing resistors. The base temperatures for each of the sensing resistors and configurations of the sensing resistors are selected to emphasize a response to a gas of interest (e.g., CO2) while de-emphasizing or canceling contributions from ambient temperature and gases that are not of interest (e.g., H2O).