Monday, May 14, 2012

Murphy vs Nordhaus vs Me summarized

It might be difficult to keep track of things in my previous post, because the lengthy discussion involves numerous claims and counterclaims. With the aim in simplifying things, here is a comment that I left on Daniel Kuehn's blog. I think that it provides a decent summary of my views:
Regarding "dancing around the issues"... Bob, my point here is that by choosing to interpret the WSJ skeptics (and Nordhaus' response) the way you do, you are either: a) Ignoring the obvious implications that they intended for their readers, or b) Rendering their specific claims as trivialities.

E.g. If you seriously believe that the skeptic claim about temperatures this decade -- i.e. "they have been flat" -- was not meant to convey any deeper message about future climate trends, do you then think that this observation is of any real use in of itself? Of course, if you think that it does say something important about long-term climate trends, which is the only thing that really matters in this debate, then you are back to the Nordhaus' response.

The Tol article is separate to the above and I do think that you highlight an important point regarding the net benefits associated with modest warming. Not many people understand this and you claim that Nordhaus badly misleads his readers by saying "Richard Tol finds a wide range of damages, particularly if warming is greater than 2 degrees"... despite the fact that Tol's own graph clearly shows net benefits up until that point. [See here - Ed.]

My response is that Tol specifically deals with this issue in his paper. He points out that these are "sunk" benefits, which we stand to accrue regardless of our policy choices today. The inertia in our climatic and economic systems will already ensure that we reach the edge of these positive gains from warming (due to increased agricultural yields, etc). Any action that we take against CO2 emissions today are solely aimed at tackling temperatures above two degrees, i.e. where things start heading into serious negative territory.

Bob, may I ask you whether you think your IER article helped readers understand this crucial point?


  1. Your still missing the point about temperature change. The skeptics said that temperatures have stayed flat for the last decade. This is true. Nordhaus can't answer them so he decides to talk about about the record since 1880 or whatever, but that is irrelevant.

    1. Your (sic) still missing the point about temperature change.

      No, my anonymous friend, you are missing the point. For the sake of the argument, however, let's assume that the WSJ skeptics really didn't imply anything beyond that statement. Again, I find this terribly unlikely, but still...

      Okay, so global temperatures have been "flat" for the last decade. Um, so what? Anyone that understands anything about climate change knows that this is a meaningless observation to make in of itself. Why do you think that climate scientists focus on 30-year averages? Answer: It's the only way to discern long-terms trend and underlying drivers. (Nevermind that this "flat" decade is easily the hottest on record.)

      This why I say that Murphy has either chosen to ignore (what I hold to be) the obvious implications of the skeptic statements... Or he only succeeds in reducing their claims to trivial points. Mind you, trivial points that are still used to sow doubt and obfuscation in a very misleading fashion. In short, textbook cherry-picking.

    2. PS- If you don't wish to take my word for it, here is the concluding statement in the Santer (2011) study that Bob Murphy chooses to reference in his own article:

      In summary, because of the effects of natural internal climate variability, we do not expect each year to be inexorably warmer than the preceding year, or each decade to be warmer than the last decade, even in the presence of strong anthropogenic forcing of the climate system. The clear message from our signal-to-noise analysis is that multi-decadal records are required for identifying human effects on tropospheric temperature. Minimal warming over a single decade does not disprove the existence of a slowly-evolving anthropogenic warming signal.

      Honestly, I don't know if it can be made clearer than that.

  2. The short termist focus of the climate skeptics reminds me of this:


No anonymous comments please. (Pseudonyms are fine.)