Those pushing for aggressive government intervention in the name of fighting climate change often claim that “the science is settled” and dismiss any dissenters as “deniers.” The so-called “consensus” is codified in the periodic reports issued by the Intergovernmental Panel on Climate Change (IPCC). The alarmist camp’s repeated references to “peer-review” and the number of organizations behind the IPCC are rhetorically very effective; they have done a great PR job in making it look as if their political solutions really do flow naturally from what the scientists in white lab coats are reporting. But allegations from IPCC authors show that politics and not science drive the process at the IPCC.

As we have documented countless times on these pages (here’s the latest example), the alarmists greatly exaggerate when they claim that aggressive and immediate government action is needed to prevent catastrophe. When you read the actual scientific literature, as opposed to the pithy summaries given by a few outspoken activists, then we see no cause for alarm. As we shall see, the latest findings stress a growing role for adaptation to a changing climate.

In the present post, I’ll walk through the recent statements issued by two bona fide experts on the economics of climate change: Richard Tol and Robert Stavins. Even though both of them played important roles in the latest IPCC report, they have publicly condemned the IPCC process as political, which distorts the underlying science and misleads policymakers and the public. Besides their impeccable credentials on this topic, Tol and Stavins are both supporters of a (modest) carbon tax. Therefore, their strong condemnations of the IPCC process should receive special attention from those who think “the science is settled” and that anyone challenging the alarmists is a “denier.” 

Richard Tol on the IPCC

Richard Tol is a Professor of the Economics of Climate Change in Amsterdam, and is one of the most-cited researchers in the field of climate change. Tol’s “FUND” computer model of the economy and climate system was one of the three selected by the Obama Administration’s Working Group on the Social Cost of Carbon. Moreover, Tol has been involved with the IPCC since 1994, and in the Fifth Assessment Report (AR5) which was released in installments beginning last September through the present, Tol was one of the two Coordinating Lead Authors of Chapter 10 from Working Group II (titled “Key Economic Sectors and Services”). Clearly, this guy is not some hack who doesn’t believe in science. On the contrary, Tol is an extremely distinguished expert on the economics of climate change, and is also directly involved with the latest IPCC report. Everyone should therefore listen very carefully to when Tol says the IPCC’s “message does not support the political agenda for greenhouse gas emission reduction.”

In a blog post from April 25, 2014, Tol writes:

As a Convening Lead Author of one of the chapters, I was automatically on the team to draft the Summary for Policy Makers (SPM). AR5 is a literature review of 2,600 pages long. It assesses a large body of scholarly publication….The SPM then distills the key messages into 44 pages…

In the earlier drafts of the SPM [for the latest IPCC assessment], there was a key message that was new, snappy and relevant: Many of the more worrying impacts of climate change really are symptoms of mismanagement and underdevelopment.

This message does not support the political agenda for greenhouse gas emission reduction. Later drafts put more and more emphasis on the reasons for concern about climate change…

The SPM, drafted by the scholars of the IPCC, is rewritten by delegates of the governments of the world, in this case in a week-long session in Yokohama. Some of these delegates are scholars, others are not…

Other delegations have a political agenda too. The international climate negotiations of 2013 in Warsaw concluded that poor countries might be entitled to compensation for the impacts of climate change. It stands to reason that the IPCC would be asked to assess the size of those impacts and hence the compensation package. This led to an undignified bidding war among delegations – my country is more vulnerable than yours – that descended into farce when landlocked countries vigorously protested that they too would suffer from sea level rise.

Many countries send a single person delegation. Some countries can afford to send many delegates. They work in shifts, exhausting the other delegations with endless discussions about trivia, so that all important decisions are made in the final night with only a few delegations left standing. The IPCC authors, who technically have the right to veto text that contradicts their chapter, suffer from tiredness too.

This shows. The SPM omits that better cultivars and improved irrigation increase crop yields. It shows the impact of sea level rise on the most vulnerable country, but does not mention the average. It emphasize[s] the impacts of increased heat stress but downplays reduced cold stress. It warns about poverty trapsviolent conflict and mass migration without much support in the literature. The media, of course, exaggerated further.

Alarmism feeds polarization. Climate zealots want to burn heretics of global warming on a stick…

The IPCC does not guard itself against selection bias and group think. Academics who worry about climate change are more likely to publish about it, and more likely to get into the IPCC. Groups of like-minded people reinforce their beliefs. The environment agencies that comment on the draft IPCC report will not argue that their department is obsolete. The IPCC should therefore be taken out of the hands of the climate bureaucracy and transferred to the academic authorities. [Bold added.]

Precisely because he could not abide by the transformation in the Summary for Policymakers (SPM) that the politicized process generated, Tol asked that his name be taken off of the SPM. He knew this would cause controversy and give ammunition to people who did not support a carbon tax (remember, Told does support a carbon tax), but he couldn’t in good conscience leave his name on the SPM when it distorted the actual peer-reviewed literature. As Tol explained to the BBC, the original message of the Summary for Policymakers was one of adaptation and manageable risks, but after the political vetting “[t]his has completely disappeared from the draft now, which is all about the impacts of climate change and the four horsemen of the apocalypse. This is a missed opportunity.


Robert Stavins on the IPCC

Robert Stavins is the Director of the Harvard Environmental Economics Program. His CV contains many publications in top economics journals as well as Science on technical details on the workings of cap-and-trade programs and other topics relevant to the economics of climate change. Stavins is one of the two Coordinating Lead Authors on Chapter 13 of the AR5’s Working Group III report (titled “International Cooperation: Agreements and Instruments”). As with Tol, so too with Stavins: This is not some intern for the Rush Limbaugh show. He is an extremely distinguished scholar in the economics of climate change, who was also very involved with the latest AR5 report from the IPCC. Those advocating aggressive government intervention therefore can’t dismiss his concerns as coming from a “denier.”

In an April 25, 2014 blog post, titled, “Is the IPCC Government Approval Process Broken?”, Stavins reproduced the April 17, 2014 letter he had sent (initially privately) to some big-wigs at the IPCC, expressing his problems with the procedure. Below I’ll reproduce some key excerpts from Stavins’ letter:

I am writing to you today to express my disappointment and frustration with the process and outcome of the government approval meetings in Berlin this past week, at which the assembled representatives from the world’s governments, considered and, in effect, fundamentally revised or rejected parts of the Summary for Policymakers (SPM) of IPCC Working Group 3 over a period of five long days (and nights)…

…[A]s the week progressed, I was surprised by the degree to which governments felt free to recommend and sometimes insist on detailed changes to the SPM text on purely political, as opposed to scientific bases.

The general motivations for government revisions – from most (but not all) participating delegations – appeared to be quite clear in the plenary sessions. These motivations were made explicit in the “contact groups,” which met behind closed doors in small groups with the lead authors on particularly challenging sections of the SPM. In these contact groups, government representatives worked to suppress text that might jeopardize their negotiating stances in international negotiations under the United Nations Framework Convention on Climate Change (UNFCCC).

I fully understand that the government representatives were seeking to meet their own responsibilities toward their respective governments by upholding their countries’ interests, but in some cases this turned out to be problematic for the scientific integrity of the IPCC Summary for Policymakers

…[N]early all delegates in the meeting demonstrated the same perspective and approach, namely that any text that was considered inconsistent with their interests and positions in multilateral negotiations was treated as unacceptable.  In fact, several (perhaps the majority) of the country representatives in the SPM.5.2 contact group identified themselves as negotiators in the UNFCCC negotiations.  To ask these experienced UNFCCC negotiators to approve text that critically assessed the scholarly literature on which they themselves are the interested parties, created an irreconcilable conflict of interest.  Thus, the country representatives were placed in an awkward and problematic position by the nature of the process.

Over the course of the two hours of the contact group deliberations, it became clear that the only way the assembled government representatives would approve text for SPM.5.2 was essentially to remove all “controversial” text (that is, text that was uncomfortable for any one individual government), which meant deleting almost 75% of the text, including nearly all explications and examples under the bolded headings. In more than one instance, specific examples or sentences were removed at the will of only one or two countries, because under IPCC rules, the dissent of one country is sufficient to grind the entire approval process to a halt unless and until that country can be appeased.

I understand that country representatives were only doing their job, so I do not implicate them personally; however, the process the IPCC followed resulted in a process that built political credibility by sacrificing scientific integrity… [T]he IPCC should not ask lead authors to volunteer enormous amounts of their time over multi-year periods to carry out work that will inevitably be rejected by governments in the Summary for Policymakers. [Bold added.]

For those who follow the policy debates over climate change, Stavins’ description should be quite eye-opening. For years, the alarmist camp has beaten dissenters over the head by saying, “Such-and-such scientific organizations, and so-and-so governments around the world, have all endorsed the latest consensus report from the IPCC…”

Yet as Stavins’ explanation reveals, this insistence on unanimous approval from government representatives obviously distorts and heavily politicizes the “Summary for Policymakers.” As Stavins wryly notes in his blog post, he and other Coordinating Lead Authors at the meetings joked that it would be more accurate to title it “Summary BY Policymakers.”


Richard Tol and Robert Stavins are truly world experts on the economics of climate change. Both have given first-hand accounts of how the IPCC process takes the actual scientific literature and distorts the results to achieve political ends. Coming from these two pillars in the field, let’s hope outsiders begin to take the rest of us seriously when we explain that the IPCC’s science does not support radically harming the economy in the name of carbon dioxide emission reductions.

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