Present scientific understanding of the problem is outlined, as are the uncertainties and the potential impacts of global warming. The technical and political scope of measures to limit greenhouse gas emissions are then examined, in relation to the industrialized market economies, the Soviet Union and Eastern Europe, and the developing world. This leads, in the concluding section, to a discussion of the major hurdles and structural constraints involved in any global strategy to limit climatic change. A postscript analyzes recent progress towards an international agreement to limit global warming (up to and including the 2nd World Climate Conference in November 1990) and discusses the key international policy issues for the early 1990s.