Personal choices drive global warming nearly as much as institutional decisions. Yet, policymakers overwhelmingly target large-scale industrial facilities for reductions in carbon emissions, with individual and household emissions a mere afterthought. Recent advances in behavioral economics, cognitive psychology, and related fields have produced a veritable behavior change revolution. Subtle changes to the choice environment, or nudges, have improved stake-holder decision-making in a wide range of contexts, from healthier food choices to better retirement planning. But the vast potential of choice architecture remains largely untapped for purposes of climate policy and action. This Article explores that untapped potential and makes the case for nudges to become a cornerstone of public and private climate governance, targeting both institutional and individual decision-making. Nudges are nimbler than most conventional regulations and adapt more readily to changing climate circumstances. Climate choice architects can build on a proven track record of successful behavioral interventions in water conservation, waste management, and other domains of environmental law and policy. Bipartisan approval of other prominent nudge campaigns demonstrates the potential of choice architecture to help defuse the increasingly polarized politics of climate change. Moreover, nudges not only improve the efficacy, efficiency, and equity of public policy but also amplify the impact of private governance action on climate change. As catalysts for more informed choices, climate nudges can further alleviate concerns over climate justice by transforming previously passive stakeholders into active decision-makers in the transition to a low-carbon economy. Despite their well-documented success, nudges have produced their share of discontents. But even the most outspoken critics support nudges that mitigate information asymmetries and remedy market failures, like the disastrous externalities imposed by greenhouse gas emissions.