Page:The Cost of Delaying Action to Stem Climate Change.pdf/19

 the outliers in different ways and include other control variables give per-decade delay estimates both larger and smaller than the regression in column (3). We therefore adopt the estimate in regression (3) of 41 percent per decade as the overall annual estimate of delay costs.

One caveat concerning this analysis is that it only considers cases in which model solutions exist. The omitted, infeasible cases tend to be ones with ambitious targets that cannot be met when there is long delay, given the model’s technology assumptions. For this reason, omitting these cases arguably understates the costs of delay reported in Table 1. Additionally, we note that estimates of the effect of a partial delay (when some developed nations act now and other nations delay action) are imprecisely estimated, perhaps reflecting the heterogeneity of partial delay scenarios examined in the studies.