The current unsustainable growth of the world economy is largely a consequence of the crisis of social capital experienced by much of the world’s population. Declining social capital leads economies towards excessive growth, because people seek, in economic affluence, compensation for emotional distress and loss of resources caused by scarce social and affective relationships. To slow down economic growth requires an increase in social capital that is a fundamental contributor to happiness. From a wide range of possible approaches to increasing present happiness, this article suggests policies that would shift the economy to a more sustainable path. It focuses on a more politically sustainable set of proposals for a green ‘new deal’ than some of those currently under discussion.