Table 4.

Comparison of principal assumptions and recommendations by economic analysts.

Assumption/Analyst	Krugman [65]	Lomborg [58]	Government Reports [63,64]	Carlin	Most Others [66–78]
Ultra-low discount rate	No	No	Yes (0.1% [63], 0.05% [64])	No	No
Optimistic technology costs	Assumes low costs—so yes	No	Yes	No (Sec. 3.2)	Yes
Energy efficiency research effective	Not discussed	Yes	Yes	No (Sec. 3.2)	Not discussed
Catastrophic threat high	Yes	No	Presumably	No (Sec. 2.5)	Varies
High CSF	Presumably	Yes	Yes	No (Sec. 2.3)	Yes
CO2 residence time in atmosphere	Presumably long	Presumably long	Presumably long	Short (Sec. 2.2 & 2.6.1)	Presumably long
Critical examination of scientific validity	No	No	No	Yes (Sec. 2)	No
Geoengineering valid alternative	Not discussed	Yes	Not discussed	Yes (Sec. 3.3)	Not discussed
Principal policy recommendation and basis	“Big bang” to reduce threat of CAGW	Energy efficiency research to reduce costs	“Big bang” to avoid “dangerous” CO2 levels	No action; geoengineering research (Sec. 3.3 & 4)	“Policy ramp” to reduce discounted costs