Under the Kyoto Protocol to the UnitedNations Framework Convention on Climate Change (UNFCCC), theindustrialized countries adopted quantified emissionreductions obligations. Marking the 10th anniversary of theestablishment of the World Bank Prototype Carbon Fund (PCF)the world's first global carbon fund, this report seeksto take stock of the World Bank's experience of workingwith the Kyoto Protocol's project-based mechanisms overthe past decade. The Clean Development Mechanism (CDM), asthe much larger system in terms of projects, emissionreductions and host countries, is the basis for much of thereport's discussion. Joint Implementation (JI) is alsodiscussed. Policy-makers and negotiators are working onadvancing the policy framework and the regulatory structuresto mitigate greenhouse gas (GHGs) at greater scale.Furthering the use of market instruments should incorporatethe lessons of the past into future designs, making full useof the experience and learning that has been gained. Thiswill mean building upon the successes of the current CDM andJI regulatory frameworks, addressing weaknesses, andabandoning what is not working. This publication seeks tomake a constructive contribution to this debate, in fullrespect of the ongoing international climate changenegotiations, by providing insights and recommendations froma practitioner's experience and perspective.