Since 2008, Menahem has also participated in the "Forum for Alternative Indicators of Riches" (FAIR more known according its French acronym) which was founded in order to monitor the activities of the "Commission on the Measurement of Economic Performance and Social Progress" chaired by Joseph Stiglitz. Following this path, he has contributed to elaborate the critical analysis of the final report of this commission. In 2011, he published on the web-site of the UNCSD "Rio + 20 Conférence" a paper arguing to enlarge well-being indicators that the United Nations general secretary will have to implement after the Rio+20 Conference. In June 2012, he participated in the Rio+20 Summit, holding a side-event and two self-organized activities in the World People Summit with two other members of FAIR, the Belgium professor Isabelle Cassiers and the French-Indian accountant Muttiah Yogananthan. Their critics were mainly devoted to criticize on environmental grounds the monetization of the sustainability approach by the World Bank and the United Nations Environment Programme (Unep). According to Georges Menahem, "the Inclusive Wealth Index (IWI), a measure introduced by the UNEP and the UN University, would make the world's environmental situation worse: if it is adopted and widely used, it could be very dangerous. It underestimates the depletion of natural resources and overestimates the monetized outcome of GDP, such as GDP and human capital".