The principles that ought to guide our one-way relations with future generations depend profoundly on the precise nature of what is being provided to or - in this case, inflicted on - them. Most discussions of intergenerational justice assume that some benefit is being provided to the future. In the case of the accelerating rate of climate change, we face a dilemma. Business-as-usual on our part will make the environment for future generations less hospitable to human enterprises, especially agriculture, than the environment is for us and has been for previous generations, leaving the situation worse than it is now and worse than it would need to be. On the other hand, rapid climate change can be stopped only if emissions of greenhouse gases in general, and carbon dioxide in particular, are limited. Any firm limit will make remaining cumulative emissions zero-sum, so that we will be competing with our own descendants for the limited remaining budget of allowed emissions. This dilemma gives responsibility to future generations a radically different shape in this case.