Manzi writes,

think that Weitzman has seriously engaged on the AGW issue at a unique level of depth. I admire his tenacity, seriousness and intellectual creativity in refusing to shrink from the issue. But he has tried to cross a bridge too far. We can not (yet) reliably quantify these alternative risks, and must (for now) live with uncertainty.

Read the whole thing. I wrote about Weitzman here.

Pointer from Tyler Cowen, who concludes

The most serious critique of Weitzman, in my view, is simply that governments are bad at getting people to bear large costs to insure against low probability events, especially when the costs accumulate each year and there is little positive feedback in the interim. (“Reelect me, our costly tax held back global warming for yet another four years! Things didn’t get worse!” does not thrill.) …As a general rule of thumb, when it comes to risk the alternative is public overworry or public underworry, don’t ever expect to hit that sweet spot in between or even get close.