People following this blog (assuming there are any) know Richard Tol and I had a disagreement recently. I basically accused him of rewriting the Aggregate Impacts section of the recent Intergovernmental Panel on Climate Change's (IPCC) Fifth Assessment Report (AR5) to make it favor his own work while excluding important information and other, more modern, work.
They'll also know Tol's response when this issue was first brought up (by Bob Ward) was to tell what was aruably a lie:
In fact, that section was moved from Chapter 19 to Chapter 10. As far as I am aware, Mr Ward did not raise this concern with the IPCC. He was informed no later than 2 April 2014 that the text was moved rather than added.
The reality is the text Bob Ward referred to bears no resemblance to the text Tol claimed was moved. The text was completely rewritten, a fact Tol has since acknowledged. Unfortunately, it appears Tol has made another false claim, one which he refuses to correct or back up. Today I'll discuss that claim and what evidence is available regarding it.
When Richard Tol admitted the section in question had been completely rewritten, he defended the revisions:
The comments on the Second Order Draft called for a complete revision, so that’s what was done.
I don't believe the "comments on the Second Order Draft called for a complete revision." I examined the expert reviewers' and government comments on that draft when I first wrote about this topic. I found nothing which called for such revisions. I've since come across documentation for nearly all of the (formal) reviews of the section.
Each IPCC assessment report goes through four different versions: Zero-Order Draft (ZOD), First-Order Draft (FOD), Second-Order Draft (SOD), Final Draft (FGD). Review comments are submitted for the first three of these. Review Editors examine these submitted comments and prepare reports summarizing what corrections the comments call for. Most of these documents are publicly available. For Chapter 19, where the section in question originated, we have:
WGIIAR5-Chap19_ZODall with AR5ZODCh19_comments
WGIIAR5-Chap19_FODall with AR5FODCh19_comments
First-Order Draft Review Editor summaries (from RE_FOD_Report_Chap19_Brklacich and RE_FOD_Report_Chap19_Semenov)
WGIIAR5-Chap19_SODall with AR5SODCh19_comments
As far as I can tell, the only (formal) material not available is any Review Editor summaries created for the ZOD and SOD. Neither is essential.
The Aggregate Impacts section of the ZOD was 19.3.6 and had two subsections. A number of changes were suggested in review comments. The text was significantly changed for the FOD. The new version was 126.96.36.199, had no subsections and contained many textual changes. Even so, many key ideas were carried over. One example is the discussion of the "social cost of carbon" (SCC).
The comments on the FOD did not call for many changes. This led one review editor to praise the chapter, saying:
The majority of the reviewers clearly offer a vote of confidence to the Ch 19 writing team. Congratulations!! The FOD is thorough and builds upon the TAR and AR4. It has made substantial progress in capturing recent advances in integrating climate and non-climate factors as well as natural and human systems in order to address risks & vulnerabilities.
This praise is interesting considering some criticisms I leveled against the final version of the section. Namely, I criticized it for not referencing past IPCC reports (it doesn't build upon TAR and AR4), and I criticized it for not "capturing recent advances" (its central thrust relies upon work from 2006 and before).
As would be expected, the text of the section remained relatively unchanged. The only substantial change to the section was the addition of a couple new paragraphs. That means the core components of the chapter passed review without complaint and were included in the SOD. They passed another round of review without complaint (as discussed before).
It was only at this point, after the section had passed two rounds of review, that the section was completely rewritten. Richard Tol claims the section was rewritten in response to "comments on the Second Order Draft," yet I can find nothing in the record I've provided above to support that claim. There are a couple documents missing from the record, but I can see no way they'd support Tol's claim either.
I directly asked Tol to clarify his claim several times. I asked him to say which comments called a complete revision of the section. He responded to several comments I made trying to elicit this information, but in each case, he failed to address the issue in the slightest. It appears he is trying to avoid it.
For people who are curious, I'm also providing the documents for Chapter 10, the chapter the final version of the section was "moved" to:
WGIIAR5-Chap10_ZODall with AR5ZODCh10_comments
WGIIAR5-Chap10_FODall with AR5FODCh10_comments
First-Order Draft Review Editor summary (from RE_FOD_Report_Chap10_Kheshgi)
WGIIAR5-Chap10_SODall with AR5SODCh10_comments
There were also several drafts of outlines of the IPCC report. WG2_AR5Outline-FINAL is the final version of it. It lists the Aggregate Impacts section as belonging in Chapter 19.
With that, I've exhausted all information I have access to without finding any support for Tol's claim. It appears no comments made as part of the IPCC process called for this section to be completely rewritten. That makes Tol's claim appear to be misleading, if not completely false.
If there were any such comments, Richard Tol or the IPCC ought to provide evidence of them. Until that happens, the evidence we have suggests Richard Tol rewrote a section of the IPCC report to remove information, exclude many references and promote his own views and work. It further suggests Richard Tol has knowingly made false claims to cover this up.
In the meantime, I'm making all information I have access to available so people can check and see if I've missed something. Credit for much of that information belongs to Donna Laframboise, who made it available here.