The first major part of this paperfocuses on tracking, monitoring, and reporting various typesof flows, primarily from ODA (Official DevelopmentAssistance) and other public sources but also from privatesources. It briefly reviews available information on variouscurrent and upcoming financial and investment flows tosupport climate action in developing countries as a firststep in assessing the challenges associated with monitoringsuch flows. It considers both climate finance (the amount ofadditional resources required to catalyze the shift of amuch larger volume of public and private developmentinvestments to climate friendlier options) and underlyingfinance (the almost 10 to 20 times larger amount offinancial and investment flows in developing countries thatmust increasingly focus on climate action). The next part ofthe paper focuses on possible ways of tracking additionalityin ODA flows, with the aim of stimulating a discussionwithin the World Bank Group (WBG) and its partners on thisissue. It describes the various perceptions of differentgroups of countries as well as possible baselines,benchmarks, and tools for tracking progress. Increasinglyreliable, comprehensive, and transparent reporting is neededto demonstrate that new climate finance instruments are notintroduced at the expense of those targeting otherobjectives. The final section provides proposals for furtheraction by industrial and developing countries, the U.N.system and multilateral development banks (MDBs).