---
title: "Criticism of the IPCC Fourth Assessment Report"
chunk: 5/5
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"
---

=== Grey literature ===
The report was also criticized by The Sunday Telegraph for using grey literature. Examples they gave included the use of non-peer reviewed sources from the International Union for Conservation of Nature and the World Wildlife Fund, and student dissertations. IPCC rules permit the use of non-peer-reviewed material, subject to critical assessment and review of the quality and validity of each source. Climate expert Martin Parry, who had been co-chair of the working group on impacts for IPCC AR4, said of  "grey literature" such as reports from campaign groups and governments that "many such reports are intensively reviewed, both internally and externally. Even if not peer-reviewed, there are reports that contain valuable information."

== Response to criticisms ==
The focus by the media on errors found in the Fourth Assessment Report resulted in a number of responses from the scientific community.
In February 2010 the International Council for Science (ICSU) released a statement indicating that "in proportion to the sheer volume of the research reviewed and analyzed, these lapses of accuracy are minor and they in no way undermine the main conclusions" and "That these errors have resulted in attempts to discredit the main conclusions of the report, accusations of scientific conspiracies, and personal attacks on scientists is unacceptable".
On March 12, 2010, an open letter was released signed by Gary Yohe, Stephen Schneider and Cynthia E. Rosenzweig along with 249 other scientists, the vast majority of whom were climate change scientists working at leading U.S. universities, including both IPCC and non-IPCC authors. The opening of the letter stated:

Many in the popular press and other media, as well as some in the halls of Congress, are seizing on a few errors that have been found in the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) in an attempt to discredit the entire report. None of the handful of mis-statements (out of hundreds and hundreds of unchallenged statements) remotely undermines the conclusion that "warming of the climate system is unequivocal" and that most of the observed increase in global average temperatures since the mid-twentieth century is very likely due to observed increase in anthropogenic greenhouse gas concentrations.
Two months later on May 6, 2010, another open letter from 255 members of the U. S. National Academy of Sciences including 11 Nobel laureates stated that they were "deeply disturbed by the recent escalation of political assaults on scientists in general and on climate scientists in particular". They outlined scientific methodology and the conclusions of climate science, in contrast to "recent assaults on climate science and, more disturbingly, on climate scientists by climate change deniers." Regarding the mistakes found in the report, the letter expressed:

The Intergovernmental Panel on Climate Change (IPCC) and other scientific assessments of climate change, which involve thousands of scientists producing massive and comprehensive reports, have, quite expectedly and normally, made some mistakes. When errors are pointed out, they are corrected.
But there is nothing remotely identified in the recent events that changes the fundamental conclusions about climate change.
In July 2010, the Netherlands Environmental Assessment Agency put forward a publication stating that it had "found no errors that would undermine the main conclusions in the 2007 report of the Intergovernmental Panel on Climate Change (IPCC) on possible future regional impacts of climate change". Among the key findings the publication mentions:

Overall the summary conclusions are considered well founded, none have been found to contain any significant errors. The Working Group II contribution to the Fourth Assessment Report shows ample observational evidence of regional climate change impacts, which have been projected to pose substantial risks to most parts of the world, under increasing temperatures.

== See also ==
 Global warming portal

== References ==

== Further reading ==
"A critique of the Stern and IPCC analyses of CO2 mitigation: Consumer-capitalist society cannot solve the problem" Ted Trainer, The International Journal of Inclusive Democracy, vol 4, no 4, October 2008.
"From Inside and Out, Climate Panel Is Pushed to Change" by Andrew Revkin, New York Times "Dot Earth", January 26, 2010