This lack of common definition represents a major challenge in establishing a MRV framework of climate finance because there is no agreed basis for measurement or methodology for tracking climate finance flows. Following Corfee-Morlot et al. Consistent with the terms of the Cancun Agreements, these may be either international public or private financing flows, and thus may be either concessional (public) or non-concessional flows (where the latter concerns private as well as some forms of public finance flows).