A transaction that transfers carbon credits between two parties under the Kyoto Protocol. The buyer pays the seller cash in exchange for carbon credits, thereby allowing the purchaser to emit more carbon dioxide into the atmosphere. The standards for this agreements are outlined by the International Emissions Trading Association.

|||This agreement usually involves two countries; however, it may occur between a country and a large corporation. Buyers expect their carbon emissions to be above the level allocated to them by the Kyoto Protocol, while the seller expects to produce less. Often, the seller has implemented new technology or is developing a new project that is expected to lower its greenhouse gas emissions.