Is drastic action against global warming essential to avoid impoverishing our descendants? Or does it mean robbing the poor to give to the rich? We do not yet know. Yet most of us can agree on the importance of minimising expected deprivation. Because of the vast number of future generations, if there is any significant risk of catastrophe, this implies drastic and expensive carbon abatement unless we discount the future. I argue that we should not discount. Instead, the rich countries should stump up the funds to support abatement both for themselves and the poor states of the world. Yet to ask the present generation to assume all the costs of drastic mitigation.is unfair. Worse still, it is politically unrealistic. We can square the circle by shifting part of the burden to our descendants. Even if we divert investment from other parts of the economy or increase public debt, future people should be richer, so long as we avert catastrophe. If so, it is fair for them to assume much of the cost of abatement. What we must not do is to expose them to the threat of disaster by not doing enough.