Realistic economic trade-offs of policies designed to reduce carbon emission are seldom addressed by environmentalists outside the Copenhagen Consensus, so it is refreshing to see this issue brought up in this journal. Even though the authors rightly emphasis the problem of using agricultural land for biofuel (a policy that I have always strongly opposed), they also touch upon the high cost of carbon reduction technology, which in turn gives consumers less disposable income. The proponents of "full world economics" are well aware of the trade-offs of environmental policies. To address the economic cost and its disparate impact on they poor, they recommend a more progressive income tax. Despite my disdain for demagogues who rail against "income inequality" I credit these authors for their economic realism about the adverse consequences of some environmental policies. I should hope that this disparate impact can be addressed by something other than a more progressive income tax because punishing success is unsustainable.