The Clean Development Mechanism (CDM) of the Kyoto Protocol is the first global attempt to address a global environmental public goods problem with a market-based mechanism. The CDM is a carbon credit market where sellers, located exclusively in developing countries, can generate and certify emissions reductions that can be sold to buyers located in developed countries. Since 2004 it has grown rapidly and is now a critical component of developed-country government and private-firm compliance strategies for the Kyoto Protocol. This Article presents an overview of the development and current shape of the market, then examines two important classes of emission reduction projects within the CDM and argues that they both point to the need for reform of the international climate regime in the post-Kyoto era, albeit in different ways. Potential options for reforming the CDM and an alternative mechanism for financing emissions reductions in developing countries are then presented and discussed.