[en] A common paradigm when the reduction of emissions from deforestations is estimated for the purpose of promoting it as a mitigation option in the context of the United Nations Framework Convention on Climate Change (UNFCCC) is that high uncertainties in input data-i.e., area change and C stock change/area-may seriously undermine the credibility of the estimates and therefore of reduced deforestation as a mitigation option. In this paper, we show how a series of concepts and methodological tools-already existing in UNFCCC decisions and IPCC guidance documents-may greatly help to deal with the uncertainties of the estimates of reduced emissions from deforestation