Zach, you seem to be implying that the Dasgupta criticism is about this kinds of claim: "the Stern estimation is that doing nothing and suffering the consequences will cost between 5-20% of GDP, so sacrificing 1% clearly makes sense." As framed, that "makes sense" is a practical, technocratic kind of "makes sense", not entirely dissimilar ot the way in which it makes sense if you have any sort of future horizon to take measures to pay off your most expensive debts, rather than letting them accrue. But Dasgupta is concerned with an _ethical_ parameter of Stern's argument, not a practical one; in particular, he is concerned that there's an incongruity between how Stern views synchronic as opposed to diachronic distributional inequalities.

(Or, um, that's what it looks like to me, anyway. Me no expert neither!)

Actually, it is DeLong's penultimate paragraph to which I was refering. And besides, the exact nature of the quibble is beyond the scope of this post, since the rest of the argument proceeds from taking the Stern numbers as given.

I agree that it doesn't impact the latter two paragraphs of the post. But regarding the first paragraph, this isn't just a quibble -- I believe that you are significantly misrepresenting DeLong (in his agreement with Dasgupta about eta, and thus misrepresenting Dasgupta as well) as raising problems for the non-normative parts of the Stern report. But the debate about the ethically appropriate value of eta is a normative one.

I'm sure you can find some other non-libertarian economists out there to support your point in the last part of your first paragraph. But as near as I can tell, your link to this particular argument by this particular economist, fails to do so.

I wonder what costs will be incurred by rapidly melting ice sheets that would put most of the city I live in (NYC) under water, prolonged droughts and heat waves, powerful hurricanes in new areas, and the likely extinction of 50 percent of species. That's what we'll be facing according to climate researcher and NASA scientist James Hansen if we don't limit the increase in global temperatures to 1.8 degrees Fahrenheit within the next 10 years.
And once climate change occurs, it will be irreversible.

Zach,
http://www.theotherjournal.com/print.php?id=171

That post describes one Christian perspective on environmentalism.

It certainly is an interesting take on why environmentalism resonates so well with modern man.

JohnS--Not that I buy into it, but it would be interesting to know if Hansen's hypothesis is his most likely scenario or the worst case amongst a group of more likely ones. Also, what does Hansen suggest we do to avoid his scenario? Would changing all lightbulbs to flourescent do the trick or would we all have go back to candles and whale oil for lighting?

ucfengr

It's the scenario. Period.

An increase of 1.8 degrees Fahrenheit (about 1 degree Celsius) over the next decade would probably be catastrophic. The question, I think, is how likely that is to occur, given that the temperature has increased by that much in the last century