Sunday, February 08, 2015

Journal of Economic Perspectives Editor Tries Once More

The winter 2015 issue of the Journal of Economic Perspectives has what the editor hope is a final word on “The Economic Effects of Climate Change” by Richard S. J. Tol and the several errors therein.

In early 2014, the editors received a complaint pointing out errors in the paper: specifically, several estimates had not been accurately transferred from the original studies. In the Spring 2014 issue, we published a “Correction and Update: The Economic Effects of Climate Change” (vol. 28, no. 2, pp. 221–26) by Richard Tol. However, this version also contained errors that were soon pointed out by various researchers. The editors discussed the situation with Richard Tol and with outside reviewers at some length.
Now followers of that little back and forth might want to do a bit of reading here at Rabett Run
Tol's Demon
A Statistical Analysis of Tol's Demon

and then there's physics
Tol's corrections

over there at Retraction Watch
Gremlins” caused errors in climate change paper showing gains from global warming

and whoa, certainly at Andrew Gelman's
Richard Tol's Gremlins Drive Iffy Policy Recommendations
A Whole Fleet of Gremlins

As Frank Ackerman pointed out in a scholarly matter, there is not much there in that figure with multiple numbers of the few points coming from the same models over a couple of decades.

Eli would have enjoyed listening in to the exchange of views at JEP, but the JEP editor has settled on using the figure appearing in the AR5

A point of continuing discussion, here at RR has been is whether the several cited studies have any coherent message, for example, can a responsible economist fit the data.  JEP thinks not
The original figure in the 2009 JEP article estimated a best-fit line passing through the points on this kind of figure, along with confidence intervals for that Figure 1 estimate. Given the differences across the studies as mentioned in the IPCC report, several outside reviewers involved in our editorial process expressed a concern that such estimates were not meaningful. As shown, the figure in the IPCC report does not seek to estimate a best-fit line or confidence intervals, but only offers a summary of the results from existing studies. Tol offers further discussion of the curve-fitting issues with this kind of data in “Bootstraps for Meta-Analysis with an Applicationto the Impact of Climate Change,” forthcoming in Computational Economics (doi: 10.1007/s10614-014-9448-5).
Of course, Richard Tol's original correction included a rather forced fit

Which Richard defended vociferously as being even more or less (who remember, who cares) pessimistic than the original.  If anybunny is interested the Computational Economics paper looks like a great pinata.  As far as Eli can see, JEP is washing its hands of the embarrassment.


Hank Roberts said...

Perhaps reading something else .....

Where once a healthy skepticism of science was a progressive impulse, more recently a radical, dangerous and insanely unhealthy skepticism of science has become very much a fact on the conservative side of the ledger. Which is the balance that Riordan is striving for in his book: the need to really understand the biases and unspoken politics of science — the relationship between nature, power and science — but at the same time we need to respect and understand the process of science. Scientific consensus has a value in helping us understand the world. In particular for many environmental issues such as climate change and resource exploitation, scientific evidence is the best bet we have to help us understand the past, present and future of our fragile planet. Riordan sees a need to be honest with ourselves about what science is good for. We need to have an honest perspective about the place of humankind in nature. We need a science in the public interest. ...
I would recommend this book to any library that collects about science and society or science policy. This book would also be appropriate for any public library and perhaps even high school libraries where young minds could be inspired to be fearless, speak truth to power and change the world.
Riordan, Michael. Bold Scientists: Dispatches From The Battle For Honest Science. Toronto: Between the Lines, 2014. 256 pp. ISBN 9781771131247.

Fernando Leanme said...

I find the lack of data points in the 1.8 to 2.2 deg C range to be quite puzzling. One would think this area would be the subject of intense study, given the 2 degree C limit they claim to have.

The lack of focus on this region tells me the scientific and economics communities are missing a few nuts and bolts. I spent quite a few years assembling and judging complex integrated analyses for a large corporation, and I would give the IPCC, the politicians behind them, and anybody who has any influence in this field a fat ZERO. I realize the models are fuzzy and will have a lot of scatter, but the avoidance of the critical target temperature in these studies is a disgrace. Every time I look at these stupid plots I feel like taking a ruler and smacking the iPCC members on the head.

Anonymous said...

@-Fernando Leanme
"I find the lack of data points in the 1.8 to 2.2 deg C range to be quite puzzling. One would think this area would be the subject of intense study, given the 2 degree C limit they claim to have. "

I agree, given the intense debate (?!) about the decimal excpansion of climate sensitivity in just this range, the lack of economic projections over the same range is unfortunate.

I wonder if it represents a split in method between projections of small changes, that can be derived from existing measured change and limited extrapolation from that; with longer-term modeling of the bigger changes implied by larger climate/sea level alterations.

For small increases, the current response to warming in agricultural production and adaption can for econometricians look like a net positive, although as others have pointed out, the climate signal of harm/benefit of extreme weather incidence can be overlaid by changinging technology and infrastructure. Extrapolating those effects much beyond a degree C or so would not look credible from present conditions because of the impact of other changes that are inevitable with a larger increase. The shift of climate/rainfall zones and sea level rise.

So as with the issue of climate sensitivity, the values derived from current data look better than the impacts implied by modeling of a more uncertain future. Giving some the opportunity to claim it isn't as bad as we might fear. And other to claim it could be worse than we think.

Meanwhile the details of what DOES happen to a climate 2.05degC warmer than the 20thC average, and to the world agricultural economy, seems to be lost in the middle.


Unknown said...

Of course, the IPCC reports are based on the literature: they don't do their own studies. Therefore, chastising them for missing studies is an illogical strategy. Is it desirable for the IPCC to push specific lines of research? That would really give the deniers a field day.