Roberts is absolutely right in responding to Manzi on the issue of efficiency that massive public utility monopolies/regulation stands in the way; and both are right that policies that unblock these markets and created more freedom wqould generate more wealthy than the status quo.

Manzi also misses other regulatory favors that are provided for coal, which is tremendously environmentally costly. Taxing and rebating carbon would push us away from this resource to nuclear, and we`d be tremendously better off in the future even if climate sensitivity fortunately turns out to be very low.

Finally, arguments about GDP are not libertarian (impossible to aggregate preferences) and measurements of GDP are themselves flawed, by ignoring damage to capital and treating expenses to adapt and repair damages as a contribution to GDP. GDP embodies the broken window fallacy.
 

Also, if we focus on human preferences here, one cannot deny the value that many place on mitigating possible temperature increases, and Elinor Ostrom in a recent piece points out (like Gene Callahan has) the legitimacy and need for action by society on the individual, group and community level.