Systems and methods are provided for managing carbon emission credits at a fuel dispensing station via a portable computing device. An exemplary method comprises: receiving a request via a communications network for a transaction at a fuel dispensing station; determining a pump identifier associated with the fuel dispensing station; receiving a user selection of a carbon offset for the transaction; sending a message to a store controller associated with the pump identifier for an amount for the selected carbon offset; receiving the amount for the carbon offset; receiving a gas payment amount for the transaction; and initiating processing of a payment comprising the gas payment amount and the amount for the carbon offset.