An online interactive method and system for trading emission reduction credits (ERC) representing a calculated value for the reduction of a given quantity of emissions from a carbon sink is provided. The method and system include (a) receiving from a seller having a seller's account data representative of a carbon sink including data representative of the type of carbon sink and the location of the carbon sink; (b) calculating a value representative of the carbon sink of the seller; (c) creating a tradable emission reduction credit (ERC) based on the value; (d) assigning an ERC identification to the emission reduction credit (ERC) for tracking purposes; (e) associating the emission reduction credit (ERC) with the seller's account using the ERC identification; (f) making the emission reduction credit (ERC) available for purchase; (g) receiving a purchase request from a purchaser having a purchaser's account for the emission reduction credit (ERC); and (h) moving the emission reduction credit (ERC) from the seller's account to the purchaser's account using the ERC identification.