(Which was funded and commissioned by the Copenhagen Consensus Center, but that's by-the-by.)
Tol's model is selective to a worrying degree; it takes only the most conservative benefit analyses (e.g. Nordhaus), assumes that nothing ultimately changes until 2100, and then plumps for a CO2 target that is generally associated with a probable global mean surface temperature rise of ~3 deg C; and says effectively 'well, yes, there may be additional effects to deal with (as opposed to the 450 ppm ~2 deg C raise) plans, but I don't think they'll be terribly significant' (See section 2.3: Missing Impacts).
Does the WSJ article mention the revised 550ppm atmospheric CO2 level?
No.
Nor does the Reuters article covering the same press release.
So what it is actually saying is that limiting atmospheric CO2 to 450 ppm is likely to cost more than limiting it to 550 ppm. Which is hardly news; but neither is it a fair comparison to the likes of the Stern Report.
But this is where Tol's pick-and-choose approach to the analyses comes in; by choosing the models with the lowest benefits (i.e. the most optimistic models in terms of possible climate change impacts on humanity) he is playing down the potential negative costs of a given temperature scenario - whilst at the same time talking up the hypothetical fiscal efficiency of spending a given sum of money his way.
And yes, if nothing really bad will happen anyway, it makes sense to spend the money as efficiently as possible; but if there is a genuine risk of seriously Bad Stuff happening, then you pay out double if you don't budget for it.
For all of the scenarios outlined, there is a non-zero chance that climate change will cause one or more catastrophic results; I'm talking about (for example) rainfall patterns and the presence of nuclear-armed nations in water-poor areas (such as the Pakistan/India border or the Golan Heights); I'm talking about population pressure on land that is not capable of supporting the level of use humans make of it (like Rwanda).
These are potential costs that Tol does nothing to describe - bar dismissing them as 'relatively small'.
(The Red Cross World Disasters Report 1999 discusses climate-related human costs; alas, it's no longer available online.)
So, to recap: Lomborg is quoting the result from a somewhat selective study that he commissioned and using them to make an apples-to-oranges comparison to policy recommendations coming from Stern and the UN Environment Programme.
Again, Lomborg and Tol are both recommending limiting atmospheric CO2 to 550 ppm. The IPCC recommends a maximum of 450 ppm; and there are a number of scientists such as Hansen arguing for a reduction to 350 ppm to minimise risk to the biosphere.
Now, as you have agreed, Lomborg (and Tol) are not physical scientists. On what basis are they advocating a level of atmospheric CO2 that is a) greater than the IPCC recommendation and b) significantly greater than the stated opinion of James Hansen, who is a physical scientist in the relevant field?
It's getting a bit long; I'll post the Simon reply below.
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branchandroot
no subject
Date: 2010-01-07 02:14 am (UTC)Let's take an easy example from the WSJ article; the model Lomborg cites as costing 12.9% of GDP is by Richard Tol (The Analysis of Mitigation as a Response to Climate Change)
(Which was funded and commissioned by the Copenhagen Consensus Center, but that's by-the-by.)
Tol's model is selective to a worrying degree; it takes only the most conservative benefit analyses (e.g. Nordhaus), assumes that nothing ultimately changes until 2100, and then plumps for a CO2 target that is generally associated with a probable global mean surface temperature rise of ~3 deg C; and says effectively 'well, yes, there may be additional effects to deal with (as opposed to the 450 ppm ~2 deg C raise) plans, but I don't think they'll be terribly significant' (See section 2.3: Missing Impacts).
Does the WSJ article mention the revised 550ppm atmospheric CO2 level?
No.
Nor does the Reuters article covering the same press release.
So what it is actually saying is that limiting atmospheric CO2 to 450 ppm is likely to cost more than limiting it to 550 ppm. Which is hardly news; but neither is it a fair comparison to the likes of the Stern Report.
But this is where Tol's pick-and-choose approach to the analyses comes in; by choosing the models with the lowest benefits (i.e. the most optimistic models in terms of possible climate change impacts on humanity) he is playing down the potential negative costs of a given temperature scenario - whilst at the same time talking up the hypothetical fiscal efficiency of spending a given sum of money his way.
And yes, if nothing really bad will happen anyway, it makes sense to spend the money as efficiently as possible; but if there is a genuine risk of seriously Bad Stuff happening, then you pay out double if you don't budget for it.
For all of the scenarios outlined, there is a non-zero chance that climate change will cause one or more catastrophic results; I'm talking about (for example) rainfall patterns and the presence of nuclear-armed nations in water-poor areas (such as the Pakistan/India border or the Golan Heights); I'm talking about population pressure on land that is not capable of supporting the level of use humans make of it (like Rwanda).
These are potential costs that Tol does nothing to describe - bar dismissing them as 'relatively small'.
(The Red Cross World Disasters Report 1999 discusses climate-related human costs; alas, it's no longer available online.)
So, to recap: Lomborg is quoting the result from a somewhat selective study that he commissioned and using them to make an apples-to-oranges comparison to policy recommendations coming from Stern and the UN Environment Programme.
Again, Lomborg and Tol are both recommending limiting atmospheric CO2 to 550 ppm. The IPCC recommends a maximum of 450 ppm; and there are a number of scientists such as Hansen arguing for a reduction to 350 ppm to minimise risk to the biosphere.
Now, as you have agreed, Lomborg (and Tol) are not physical scientists. On what basis are they advocating a level of atmospheric CO2 that is a) greater than the IPCC recommendation and b) significantly greater than the stated opinion of James Hansen, who is a physical scientist in the relevant field?
It's getting a bit long; I'll post the Simon reply below.