 From 1988, Lopes held various positions with the United Nations.He has been a representative in Brazil and in Zimbabwe, he was director of political affairs in the office of the Secretary-General, he was director for development policy at the United Nations Development Programme, he was director of the United Nations System Staff College and an executive director of the United Nations Institute for Training and Research.From 2012 to 2016 he was executive secretary of the United Nations Economic Commission for Africa.