Climate change is one, especially clear, instantiation of a profound challenge to humanity. The problem is genuinely global, dominantly intergenerational, and takes place in a setting where our theories are weak. This convergence justifies calling it a "perfect moral storm". One consequence of this storm is that, even if the other difficult ethical questions surrounding climate change could be answered, we might still find it difficult to act. For the storm makes us extremely vulnerable to moral corruption. This book explores how the perfect moral storm is manifest in climate change. It argues that despite decades of awareness, we are currently accelerating hard into the problem in a way that defies standard explanations. This suggests that our current focus on the scientific and economic dimensions of the problem is too narrow, and the tendency to see climate change as a traditional tragedy of the commons facing nation states too optimistic. The key problem is that the current generation, and especially the most affluent, are in a position to pass on most of the costs of their behavior (and especially the most serious harms) to the global poor, future generations and nonhuman nature. This diagnosis helps to explain the past failures of international climate policy, and in particular the "shadow solutions" of Kyoto and Copenhagen. It also casts light on some of the seemingly perpetual problems in our public discourse, and on the current push towards geoengineering. Finally, it suggests a need for better public ethics. We must work harder on articulating the ethical problem, and moral constraints on solutions. In the meantime, there is a role for "defensive" moral and political philosophy, aimed at preserving the quality of public discourse.