---
title: "Criticism of the IPCC Fourth Assessment Report"
chunk: 4/5
source: "https://en.wikipedia.org/wiki/Criticism_of_the_IPCC_Fourth_Assessment_Report"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:22:45.688900+00:00"
instance: "kb-cron"
---

=== Proportion of Netherlands below sea level ===
The Working Group II: Impacts, Adaption and Vulnerability report states that "The Netherlands is an example of a country highly susceptible to both sea-level rise and river flooding because 55% of its territory is below sea level". This was based on data it had received from the Netherlands Environmental Assessment Agency (the PBL). When the Dutch government raised questions, the PBL acknowledged in a statement that it had supplied the incorrect wording to the IPCC, "This should have read that 55 per cent of the Netherlands is at risk of flooding; 26 per cent of the country is below sea level, and 29 per cent is susceptible to river flooding." It used Normaal Amsterdams Peil as the datum for sea level. Martin Parry, climate expert and co-chair of the IPCC working group II, said that various different figures could have been used, depending on how the issue was defined. A figure of 60%, for land that lies below high water level during storms, is used by the Dutch Ministry of Transport, while a figure of 30%, referring to land below mean sea level, is used by others.
De Volkskrant reported Mary Jean Burer, a spokesperson for the Netherlands Environmental Assessment Agency (PBL) as saying that the confusion can partly be blamed on several EU articles by the Transport Ministry in which numbers like 55 and 60 percent land area are mixed up. "Sometimes it refers to floods, sometimes the sea level".  PBL employee Oude Lohuis added that the IPCC cannot be blamed for the fact that the statement of 55% being below sea level was not noticed. "The ministry says in some brochures that during spring tides the Netherlands is 60 % below sea level", he said, "So for outsiders it's not a strange number"

== Process issues ==
Richard Black, an environmental reporter for the BBC, once observed that the IPCC is an unusual organisation in that the evidence is supplied by scientists, but the summaries of its reports are agreed between scientists and representatives of governments.

=== Dismissal of concerns ===
In January 2005, Chris Landsea who had been an author on the 2001 report (TAR), withdrew his participation in the Fourth Assessment Report claiming that the portion of the IPCC to which he contributed had become "politicized" and that the IPCC leadership simply dismissed his concerns. He published an open letter explaining why he was resigning and to "bring awareness to what I view as a problem in the IPCC process".
Landsea alleged that lead author Kevin Trenberth had told a press conference that global warming was contributing to "recent hurricane activity", which Landsea described as a "misrepresentation of climate science while invoking the authority of the IPCC". He said that the process of producing the Fourth Assessment Report is "motivated by pre-conceived agendas" and "scientifically unsound". Landsea wrote that "the IPCC leadership said that Dr. Trenberth was speaking as an individual even though he was introduced in the press conference as an IPCC lead author."

=== Aerosol forcing uncertainty ===
The 2007 IPCC Working Group I Report quantified the effect of anthropogenic aerosols on the climate in terms of their radiative forcing. Radiative forcing measures the influence a particular factor has on changing the Earth-atmosphere-system energy balance. The effect of aerosols was assessed to be the dominant uncertainty in radiative forcing.
A 2008 Report for the US Climate Change Science Program (CCSP) suggested that the IPCC report may have been 'overconfident' with its uncertainty estimate for the total aerosol forcing. This was based on an earlier 2006 paper that elicitated the judgment of twenty-four experts on aerosol forcing. The CCSP Report went on to say:

... expert judgment is not a substitute for definitive scientific research. Nor is it a substitute for careful deliberative expert reviews of the literature of the sort undertaken by the IPCC. However, its use within such review processes could enable a better expression of the diversity of expert judgment and allow more formal expression of expert judgments, which are not adequately reflected, in the existing literature. It can also provide insights for policy makers and research planners while research to produce more definitive results is ongoing. It is for these reasons that Moss and Schneider have argued that such elicitations should become a standard input to the IPCC assessment process

=== Recommended procedural change ===
In 2007, economist and former IPCC author Richard Tol wrote a paper on the IPCC Working Group III Report. Tol said that the quality of the Working Group III Report had declined. He made several criticisms of the Report's content, and suggested changes in procedure that could improve the quality of future IPCC assessments:

It would be much better to shift the IPCC from UNEP and the environment ministries to ICSU and the ministries of research and higher education. Academic quality should be guiding principle in selecting authors. As a check, the committees that nominate and select authors should publish their proceedings. The review editors should become more independent, and gain the right to reject chapters that are not properly revised. The alternative is a gradual erosion of the quality, prestige and, eventually, influence of the IPCC.In February 2010, in response to controversies regarding claims in the Fourth Assessment Report, five climate scientists – all contributing or lead IPCC report authors – wrote in the journal Nature calling for changes to the IPCC. They suggested a range of new organizational options, from tightening the selection of lead authors and contributors, to dumping it in favor of a small permanent body, or even turning the whole climate science assessment process into a moderated "living" Wikipedia-IPCC. Other recommendations included that the panel employ a full-time staff and remove government oversight from its processes to avoid political interference.