IPCC Second Assessment Report

Overview

The Second Assessment Report, titled Climate Change 1995, consists of reports from each of the three Working Groups, and a Synthesis Report:

• Report of Working Group I: The Science of Climate Change .
• Report of Working Group II: Impacts, Adaptations and Mitigation of Climate Change: Scientific-Technical Analyses .
• Report of Working Group III: Economic and Social Dimensions of Climate Change .
• The "Full Report", consisting of Synthesis of Scientific-Technical Information Relevant to Interpreting Article 2 of the UN Framework Convention on Climate Change, and the Summaries for Policymakers from the three Working Group reports .

These reports were prepared by over two thousand experts, and "contain the factual basis of the issue of climate change, gleaned from available expert literature and further carefully reviewed by experts and governments."

The Synthesis Report gave its purpose as providing the scientific, technical and socio-economic information for determining

Conclusions

Working Group I, dealing with the scientific aspects of climate, stated that

Working Group I subsequently characterized its reports in the First and Second Assessments as progressing from an understanding that the [greenhouse effect is well understood, greenhouse gases are increasing (due largely to human activity), and therefore should lead to significant global warming (though lack of understanding limited specific regional predictions), to a greater understanding (despite continuing uncertainties) that global warming continues and is most likely due to human activity, and that very substantial cuts in emissions would be required to stabilize greenhouse gas concentrations.

1. Greenhouse gas concentrations have continued to increase
2. Anthropogenic aerosols tend to produce negative radiative forcings
3. Climate has changed over the past century
4. The balance of evidence suggests a discernible human influence on global climate
5. Climate is expected to continue to change in the future
6. There are still many uncertainties

Its eighth chapter noted "these results indicate that the observed trend in global mean temperature over the past 100 years is unlikely to be entirely natural in origin. More importantly, there is evidence of an emerging pattern of climate response to forcings by greenhouse gases and sulphate aerosols in the observed climate record. Taken together, these results point towards a human influence on global climate." [ch 8, summary, p 412].

Working Group II assessed whether the range of plausible impacts of global warming constitutes dangerous anthropogenic interference with the climate system, while Working Group III provided information to help countries "take decisions they believe are most appropriate for their specific circumstances".

Chapter 8: Detection of Climate Change and Attribution of Causes

In the IPCC process, a "convening lead author" for each chapter worked with other lead authors and contributing authors to agree the structure of the chapter, and assign teams of scientists to write each section of the chapter, producing a draft which was subject to acceptance by the whole author group. Participating governments then provided review comments on the draft, incorporated into the assessment which was presented to seek acceptance at a plenary session of the IPCC.

The IPCC chairman Bert Bolin had difficulty finding a convening lead author for Chapter 8. After delays, Benjamin D. Santer who was doing postdoctoral research on the topic was persuaded to take on the task. Twenty participants from various countries met at the initial meeting in Livermore, California, in August 1994 to identify the scientific topic areas, and discussion continued by email. At the first drafting session (in Sigtuna, Sweden, in October) Santer persuaded the others that the chapter should discuss observational and model uncertainties, though these were also covered in other chapters. The "zeroth" draft was then sent out for peer review to scientific topic experts, all the chapter authors and lead authors of other chapters. Their responses were incorporated in the second drafting session in March 1995 at Brighton. In May the entire draft Working Group I report as well as the summary for policymakers was submitted for full "country review" by participating governments, to provide comments for incorporation at the third drafting session at Asheville, North Carolina, in July. Because of the delayed timing, Santer did not receive government comments for this meeting, some did not arrive until the plenary meeting in November.

The Chapter 8 draft report put together on 5 October had an Executive Summary of the evidence, and after various qualifications, said "Taken together, these results point towards a human influence on climate." Governments at the November plenary meeting in Madrid demanded changes to how this was worded in the Summary for Policymakers, after extended discussions Bolin suggested the adjective "discernible" and this was agreed. The approved Summary for Policymakers includes a section headed "The balance of evidence suggests a discernible human influence on global climate", setting out progress in detection and attribution studies, cautioning that "Our ability to quantify the human influence on global climate is currently limited because the expected signal is still emerging from the noise of natural variability, and because there are uncertainties in key factors." Santer was subsequently required by the IPCC to bring the rest of the chapter into compliance with this wording. The summary at the start of the accepted version of the chapter stated that "these results indicate that the observed trend in global mean temperature over the past 100 years is unlikely to be entirely natural in origin. More importantly, there is evidence of an emerging pattern of climate response to forcings by greenhouse gases and sulphate aerosols in the observed climate record. Taken together, these results point towards a human influence on global climate." The final paragraph in the chapter stated "The body of statistical evidence in Chapter 8, when examined in the context of our physical understanding of the climate system, now points to a discernible human influence on global climate." An introductory preface to the SAR written by IPCC chairman Bolin and his co-chairs John T. Houghton and L. Gylvan Meira Filho highlighted "that observations suggest 'a discernible human influence on global climate', one of the key findings of this report, adds an important new dimension to discussion of the climate issue."

Prior to the publication of the Second Assessment Report, the industry group Global Climate Coalition distributed a report entitled "The IPCC: Institutionalized Scientific Cleansing" to reporters, US Congressmen, and scientists, which said that Santer had altered the text, after acceptance by the Working Group, and without approval of the authors, to strike content characterizing the uncertainty of the science. Three weeks later, and a week after the Second Assessment Report was released, the Global Climate Coalition was echoed in a letter published in The Wall Street Journal from the retired condensed matter physicist and former president of the US National Academy of Sciences, Frederick Seitz, chair of the George C. Marshall Institute and Science and Environmental Policy Project, but not a climatologist. In this letter, Seitz alleged that Santer had perpetrated "a disturbing corruption of the peer-review process." Seitz criticized the conclusions of Chapter 8, and wrote that "key changes were made after the scientists had met and accepted what they thought was the final peer-reviewed version", deleting "hints of the skepticism" he attributed to other unnamed scientists.

The position of the lead author of Chapter 8, Benjamin D. Santer, was supported by fellow IPCC authors and senior figures of the American Meteorological Society (AMS) and University Corporation for Atmospheric Research (UCAR). The presidents of the AMS and UCAR stated that there was a "systematic effort by some individuals to undermine and discredit the scientific process that has led many scientists working on understanding climate to conclude that there is a very real possibility that humans are modifying Earth's climate on a global scale."

Other rebuttals of Seitz's comments include a 1997 paper by Paul Edwards and IPCC author Stephen Schneider, and a 2007 complaint to the UK broadcast regulator Ofcom about the television programme, "The Great Global Warming Swindle". The 2007 complaint includes a rebuttal of Seitz's claims by the former IPCC chairman, Bert Bolin.

Debate over value of a statistical life

One of the controversies of the Second Assessment Working Group III report is the economic valuation of human life, which is used in monetized (i.e., converted into US dollar values) estimates of climate change impacts.This has been documented in a number of sources:

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Often in these monetized estimates, the health risks of climate change are valued so that they are "consistent" with valuations of other health risks. |display-authors=etal}}, in (p.194 of PDF) | access-date=2 January 2014 | archive-date=6 June 2013 | archive-url=https://web.archive.org/web/20130606030656/http://www.paecon.net/PAEReview/issue25/Ackerman25.htm | url-status=live For example:

• {{Cite book |chapter-url = |url-status = dead |archive-url = https://web.archive.org/web/20080910214411/http://nordhaus.econ.yale.edu/Balance_2nd_proofs.pdf |archive-date = 2008-09-10
• {{Cite web |url-status = dead |archive-url = https://web.archive.org/web/20070614024612/http://www.clivespash.org/Final_EPW_10Feb07.pdf |archive-date = 14 June 2007
• {{Cite book |url-status = dead |archive-url = https://web.archive.org/web/20130502230715/http://www.hm-treasury.gov.uk/d/Chapter_6_Economic_modelling_of_climate-change_impacts.pdf |archive-date = 2013-05-02
• {{Cite book |url-status = dead |archive-url = https://web.archive.org/web/20130516151957/http://www.hm-treasury.gov.uk/d/Chapter_2_Economics_Ethics_and_Climate_Change.pdf |archive-date = 2013-05-16
• {{Cite book |chapter-url = http://www.climatescience.gov/Library/sap/sap4-6/final-report/ |display-authors = etal |url-status = dead |archive-url = https://web.archive.org/web/20091130094759/http://www.climatescience.gov/Library/sap/sap4-6/final-report/ |archive-date = 2009-11-30 The strengths and weaknesses of monetized estimates are discussed in the SARChapter 5 of the SAR Working Group III report discusses how cost-benefit analysis (which extensively uses monetized estimates) can be applied to climate change. Other chapters (1–4, 6, and 10) also contain relevant information. and later IPCC assessments.For example:
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In the preparation of the SAR, disagreement arose over the Working Group III Summary for Policymakers (SPM). The SPM is written by a group of IPCC authors, who then discuss the draft with government delegates from all of the UNFCCC Parties (i.e., delegates from most of the world's governments). |chapter-url=http://www.nap.edu/openbook.php?record_id=10139&page=23 | archive-url= https://web.archive.org/web/20110605132107/http://www.nap.edu/openbook.php?record_id=10139&page=1| archive-date= 5 June 2011| url-status= live|bibcode=2001ccsa.book.....N The economic valuation of human life (referred to by economists as the "value of statistical life") was viewed by some governments (such as India) as suggesting that people living in poor countries are worth less than people living in rich countries. David Pearce, who was a lead author of the relevant chapter of the SAR, officially dissented on the SPM. According to Pearce: |access-date=20 May 2009 |archive-url=https://web.archive.org/web/20080716203426/http://yosemite.epa.gov/ee/epalib/nwlet.nsf/434d5673ac53b154852564cd007a8a0d/716e9f1d6b29a006852564d600141f3a%21OpenDocument |archive-date=16 July 2008 |url-status=dead

In other words, a few government delegates wanted "statistical lives" in poor countries to be valued at the same level as "statistical lives" in rich countries. IPCC author Michael Grubb |access-date = 12 December 2012 |url-status = dead |archive-url = https://web.archive.org/web/20130703201045/http://www.econ.cam.ac.uk/rstaff/grubb/SelectAct.htm |archive-date = 3 July 2013 |url-status = dead |archive-url = https://web.archive.org/web/20130703200940/http://www.econ.cam.ac.uk/rstaff/grubb/publications/GA09.pdf |archive-date = 2013-07-03

References

Sources

The Second Assessment Report consists of the following reports from each of the three Working Groups, and a Synthesis Report. The WG2 report has on-line text; all are available in PDF format at the IPCC's documents web page.

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References

1. {{Harvnb. IPCC SAR SYR. 1995, p. vii, and see [http://www.ipcc.ch/publications_and_data/publications_and_data_reports.shtml IPCC website] {{Webarchive. link. (2018-11-30 .)
2. {{Harvnb. IPCC SAR SYR. 1995, p. viii.
3. {{Harvnb. IPCC SAR SYR. 1995, Section 1.5, [http://www.ipcc.ch/ipccreports/sar/wg_I/ipcc_sar_wg_I_full_report.pdf p. 3] {{Webarchive. link. (2011-10-15 . The "dangerous anthropogenic interference with the climate system" language is from Article 2 of the [[UNFCCC). UN Framework Convention on Climate Change]] (UNFCCC).
4. {{Harvnb. IPCC SAR SYR. 1995, Preface, [http://www.ipcc.ch/ipccreports/sar/wg_I/ipcc_sar_wg_I_full_report.pdf p. xi] {{Webarchive. link. (2011-10-15 .)
5. {{Harvnb. IPCC TAR WG1. 2001, Technical Summary, Section A.2, [http://www.ipcc.ch/ipccreports/sar/wg_I/ipcc_sar_wg_I_full_report.pdf pp. 22–3] {{Webarchive. link. (2011-10-15)
6. {{Harvnb. IPCC SAR SYR. 1995, [http://www.ipcc.ch/pdf/climate-changes-1995/ipcc-2nd-assessment/2nd-assessment-en.pdf p. 27] {{Webarchive. link. (2018-09-13 .)
7. {{Harvnb. IPCC SAR SYR. 1995, [http://www.ipcc.ch/pdf/climate-changes-1995/ipcc-2nd-assessment/2nd-assessment-en.pdf p. 45] {{Webarchive. link. (2018-09-13 .)
8. (2010). "Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming". [[Bloomsbury Publishing]].
9. IPCC Second Assessment Report: [http://www.ipcc.ch/ipccreports/sar/wg_I/ipcc_sar_wg_I_full_report.pdf Climate Change 1995, WG1] {{Webarchive. link. (2011-10-15 . Summary for Policymakers, pp. 4–5)
10. IPCC Second Assessment Report: Climate Change 1995, WG1. ch 8, summary, pp. 412, 439, xi
11. Seitz, F. (12 June 1996). [http://stephenschneider.stanford.edu/Publications/PDF_Papers/WSJ_June12.pdf Major deception on global warming] {{Webarchive. link. (2013-05-30 , ''Wall Street Journal''. p. A16.)
12. Lahsen, M. (1999). The Detection and Attribution of Conspiracies: The Controversy Over Chapter 8. In [[George E. Marcus. G. E. Marcus]] (Ed.), ''Paranoia Within Reason: A Casebook on Conspiracy as Explanation'' (pp. 111–136). Chicago, IL: University of Chicago Press. {{ISBN. 0-226-50458-1.
13. Helvarg, David. (December 16, 1996). "The greenhouse spin".
14. (25 July 1996). "Special insert—An open letter to Ben Santer". UCAR Quarterly.
15. (1997). "The 1995 IPCC Report: Broad Consensus or "Scientific Cleansing"?". Ecofable/Ecoscience, 1:1 (1997), pp. 3–9.