This article examines the claim that global warming may significantly affect power relationships between North and South. It accepts that such a claim cannot be inferred from the outcome of the recent negotiations which produced a convention on climate change at the UN Conference on Environment and Development signed in Rio in June 1992. However, it argues that since some developing countries at least are projected to account for a significant and increasing proportion of greenhouse gas emissions in the future, this gives them potential leverage, which could be used in future negotiations. The article outlines this argument and objections to it, concluding that while it is by no means clear that developing countries can exercise such leverage effectively, such a potential does exist.