Despite all the science and summits, leading capitalist states have not managed to mitigate anything close to an adequate level of carbon emissions. There is no way the world will warm less than the critical 2C threshold. What are the likely political–economic outcomes? Where is our warming world headed? Possibilities in the struggle for climate justice depend on our capacity to anticipate where the existing global order is likely to go. Climate Leviathan provides a radical way of thinking about how environmental change will intensify existing challenges to the global order, unearthing the forces for a planetary variation on existing forms of sovereignty.