We confront daunting twenty-first century challenges hobbled by twentieth century institutions. In a world ever more interdependent, deepening global-scale risks—climate change, financial instability, terrorism, to name a few—threaten the planetary commonweal, even the continuity of civilization. Yet coherent and timely responses lie beyond the grasp of our myopic and disputatious state-centric political order. Closing this perilous gap between obsolete geo-politics and emerging geo-realities delineates an urgent political endeavor: constructing a legitimate and effective system of world governance. Key steps on that path involve reforming the United Nations and nurturing new venues for the meaningful exercise of global citizenship.

Adequate mitigation of the risks of climate change requires rapid displacement of fossil fuels with carbon-free energy sources. This imperative has prompted a growing chorus of energy analysts, policy makers, and industry advocates to press for a resurgence of nuclear energy. Even some environmentalists are urging reconsideration of the nuclear option, so long anathema to their own movement. Yet, with critical problems unsolved—safety and cost, waste storage, and nuclear weapons proliferation—nuclear power remains a deeply problematic response to the climate challenge, and to the wider challenge of global sustainability. Therefore, the transformative energy strategy of a Great Transition relies on three major prongs: renewable resources, deep efficiency, and a model of development based on environment-sparing consumption and production patterns.

Orion Kriegman examines the potential for a global citizens movement by drawing on relevant lessons from past and current social movements. He argues that, although the emergence of such a movement might not be probable, it is nonetheless possible at this historical moment of growing interdependence and collective risk. He addresses the missing ingredients for the development of such a movement and points to further avenues for assessing its possibilities.