Jointly with the University of Liege, the KNOMAD Thematic Working Group on Environmental Change and Migration will be hosting a workshop entitled “Quantitative Assessment of Environmentally-induced Migration” on 9-10 May 2015 at the World Bank headquarters in Washington, DC. The Global Knowledge Partnership on Migration and Development (KNOMAD) is a global hub of knowledge and policy expertise on migration and development issues (for more information see www.knomad.org) The need for this workshop1 arises from the a) lack of quantitative comprehension of the environment-migration nexus, and b) the difficulty in comparing that data which does exist on the topic. Despite the burgeoning research on the relationship between human migration and adverse environmental conditions – from sudden-onset natural disasters and extreme weather events to more gradual variations in climate and progressive environmental deterioration – there is still a relative dearth of rigorous estimates and projections of those displaced by environmental changes and a quantification of the impacts of voluntary and forced movements on migrants, destination, transit and sending zones. While a considerable number of datasets documents the environment-migration nexus, methodological and data-related limitations render cross-study comparability difficult Major constraints concern insufficiently detailed data on various socioeconomic and demographic characteristics, the definition of migrants, the choice and definition of proxy variables for environmental factors, the empirical methodology, and the geographic level of representation of data sources. Furthermore, the literature lacks a sufficient number of rigorous studies to perform a meta-analysis in the spirit of Hsiang, Burke, and Miguel (2013) for conflict.