Global climate change raises profound questions for social and political theorists. The human impacts of climate change are sufficiently broad, and will exacerbate inequalities between rich and poor countries despite the limited role of the latter in their origins. Responding to these impacts will require the implementation of environmental and social policies that are both environmentally effective and consistent with the equality and liberty of populations to which they are applied. This article considers whether global emissions trading is defensible from a liberal egalitarian perspective. After a brief review of the theory and practice of emissions trading, a number of normative objections to the international trade in emissions allowances are analysed. It is argued that instituting a global network of emissions trading schemes would be illegitimate in absence of significant procedural and consequential safeguards.