“The could question is very different from the question of “What should we do?” Any discussion of how the world should respond to a changing climate is best informed by scientific certainties and uncertainties. But it’s ultimately a discussion of values—one that weighs development, environment, and intergenerational and geographical equities in light of imperfect projections of future climates. And the could and should questions are different still from asking “What will we do?” Answering that involves assessing the realities of politics, economics, and technology development. Indeed, the simple truth is that there are many things the world could do and perhaps even should do—such as eliminating poverty—but which it will not do for various reasons. Importantly, making a judgment about will is not at all the same as stating an opinion about should.”