A Review of the <i>Stern Review on the Economics of Climate Change</i>

The <i>Stern Review</i> calls for immediate decisive action to stabilize greenhouse gases because "the benefits of strong, early action on climate change outweighs the costs." The economic analysis supporting this conclusion consists mostly of two basic strands. The first strand is a formal aggregative model that relies for its conclusions primarily upon imposing a very low discount rate. Concerning this discount-rate aspect, I am skeptical of the <i>Review</i>'s formal analysis, but this essay points out that we are actually a lot less sure about what interest rate should be used for discounting climate change than is commonly acknowledged. The <i>Review</i>'s second basic strand is a more intuitive argument that it might be very important to avoid possibly large uncertainties that are difficult to quantify. Concerning this uncertainty aspect, I argue that it might be recast into sound analytical reasoning that might justify some of the <i>Review</i>'s conclusions. The basic issue here is that spending money to slow global warming should perhaps not be conceptualized primarily as being about consumption smoothing as much as being about how much insurance to buy to offset the small change of a ruinous catastrophe that is difficult to compensate by ordinary savings.