Countries with commitments under the Kyoto Protocol to limit or reduce greenhouse gas emissions must meet their targets primarily through national measures. As an additional means of meeting these targets, the Kyoto Protocol introduced three market-based mechanisms (Emissions Trading, Clean Development Mechanisms, Joint Implementation), thereby creating what is now known as the “carbon market.”
Source: UNFCCC Website, 2014
Under the Clean Development Mechanism, emission-reduction projects in developing countries can earn certified emission reduction credits.
Under Joint Implementation, countries with commitments under the Kyoto Protocol are eligible to transfer and/or acquire emission reduction units (ERUs) and use them to meet part of their emission reduction target.