Jonathan Adler and Ronald Bailey are to be applauded for writing essays that work to convince the libertarian community that climate change is real and man-made.They argue that accepting the reality of man-made climate change does not mean that one is necessarily signing on to a particular set of policies, but on this point, I have to take issue. The best way to deal with man-made climate change is to institute a tax on carbon emissions that is revenue-neutral, and can go back to taxpayers in the form of a payroll tax refund. Back in 2007, I argued in favor of using the carbon tax and futures markets to settle the debate over whether the planet is warming. But that debate is indeed settled, and now, the carbon tax is needed in order to stop or reverse warming. And if we don’t act quickly enough, we will need to add geo-engineering to the list of policy options. Indeed, employing geo-engineering may already be necessary.