Is the city good or bad for climate? You would think we would know. Stories abound in newspaper op-eds, policymaker commentaries and climate reports about the presumed environmental benefits of cities. For critical urban theorists the goodness and greenness of the city is not always so evident, but so far critical urban theory seems unable to shift the emerging consensus about the state of the city at the possible end of the planet. I examine urban theory in a space and time of planetary boundaries. Bringing critical urban theory into dialog with ideas from ecological economics and land change science about urbanization and a not-boundless planet, I show that foundational ideas about cities have been externalizing, not only as processes but also as concepts. Paying closer attention to the nature of socionatural change and critical urban theorists’ own theoretical precepts, I probe the limitations and possibilities of particular urban theoretical frameworks to take on problems of planetary nature. I end with a proposition for a meshwork of urban frameworks—interfaces between urban frameworks and other ways of seeing processes of planetary significance—and a view on the political stakes of a better way to see city and planet.