The Intergovernmental Panel on Climate Change (IPCC) is a group of scientists chosen by governments and other large groups from around the world who study the way that humans are making the Earth heat up unnaturally. The group was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), two organizations of the United Nations.

The IPCC shared the 2007 Nobel Peace Prize with former Vice President of the United States Al Gore who won for working on the same problems.

A lot of IPCC work is publishing reports about the United Nations Framework Convention on Climate Change (UNFCCC),  an international agreement that human inventions and chemistry may make the Earth too hot to live on. The UNFCCC was the beginning of the Kyoto Protocol. Members of the IPCC read, write, and calculate as much as they can. Only member states of the WMO and UNEP may be members of IPCC.
A lot of professors trust the IPCC work.

IPCC Reports 
The first IPCC report was published in 1990. More was added to that report in 1992. The second report was published in 1995, the third was published in 2001, and a fourth in 2007. Each report is in three books called Working Groups 1, 2 and 3. Most times "the IPCC report" means the Working Group I report, which is about basic climate change.

IPCC Fourth Assessment Report: Climate Change 2007 
The Fourth Assessment Report (AR4) was completed in early 2007. Like earlier IPCC reports, it contains four reports, three of them from its working groups.

Working Group 1 was about the "Physical Science Basis of Climate Change."
The Working Group 1 report was published on February 2 2007 and revised on February 2007. There was also a February 2 2007 press release.  The full Working Group 1 report was published in March. The main report says:
 Warming of the climate system is unequivocal.
 Most of the increase in globally averaged temperatures since the middle of the 20th century is very likely to be caused by humans using gases such as carbon dioxide, methane, and CFCs.
 Warming and sea level rise will continue for centuries, even if greenhouse gas was not used any more, the amount of warming and sea level rise depends on how much fossil fuel is burnt for the next 100 years (pages 14 and 18).
 The chance that global warming and rising sea levels is natural is less than 5%.
 World temperatures could rise by between 1.1 and 6.4 °C (2.0 and 11.5 °F) during the 21st century (table 3) and:
 Sea levels may rise by 18 to 59 cm (7.08 to 23.22 in) [table 3].
 Both past and future carbon dioxide production will continue to make global warming and sea level rise for more than a thousand years.
 Carbon dioxide, methane, and nitrous oxide in the atmosphere have increased a lot because of human activities since 1750

The Summary for Policymakers for the Working Group 2 (IPCC wg2 ) report was published on April 6, 2007.
The Summary for Policymakers for the Working Group 3 report  was published on May 4, 2007.

IPCC Third Assessment Report: Climate Change 2001 

The Third Assessment Report (TAR) contains four reports, three of them from its working groups:
 Working Group 1: The Scientific Basis
 Working Group 2: Impacts, Adaptation and Vulnerability
 Working Group 3: Mitigation
 Synthesis Report

The "headlines" from the Summary for Policymakers in The Scientific Basis were:

 More scientists are believing in a warming world and other changes in climate (The average global temperature has increased during the 20th century by about 0.6 °C; Temperatures have risen during the past four decades in the lowest 8 kilometers of the atmosphere; Snow and ice have decreased)
 Emissions of greenhouse gases and aerosols due to human activities continue to change the atmosphere in ways that are expected to affect the climate
 More scientists believe future climate change can be predicted. Climate prediction has improved but not enough
 There is new and stronger evidence that most of the warming over the past 50 years was caused by humans
 Humans will continue to change atmosphere in the 21st century
 Global average temperature and sea level are projected to rise by the IPCC SRES scenarios

The estimate for the climate sensitivity was 1.5 to 4.5 °C; and the average temperature was predicted to increase by 1.4 to 5.8 Celsius degrees between 1990 and 2100, and the sea level was predicted to rise between 0.1 and 0.9 meters.  The range of predictions is based on different levels of human carbon dioxide production. Each perdiction has different possible outcomes.

Changing scientists reports 

MIT professor Richard Lindzen, who works for the IPCC Working Group 1, claims some of the IPCC reports are wrong. He told the U.S. Senate Committee on Commerce, Science and Transportation that he was unhappy about the Executive Summary based on his work in May 2001. He said that he told the IPCC they were making mistakes and the Working Group 1 report said that meant they were "making improvements".

Professor Lindzen said:

The summary does not reflect the full document... For example, I worked on Chapter 7, Physical Processes. This chapter dealt with the nature of the basic processes which determine the response of climate, and found numerous problems with model treatments – including those of clouds and water vapor. The chapter was summarized with the following sentence: 'Understanding of climate processes and their incorporation in climate models have improved, including water vapor, sea-ice dynamics, and ocean heat transport.'

The Working Group 1 report said:
  Coupled models can provide credible simulations of both the present annual mean climate and the climatological seasonal cycle over broad continental scales for most variables of interest for climate change. Clouds and humidity remain sources of significant uncertainty but there have been incremental improvements in simulations of these quantities.
 Confidence in the ability of models to project future climates is increased by the ability of several models to reproduce the warming trend in 20th century surface air temperature when driven by radiative forcing due to increasing greenhouse gases and sulphate aerosols. However, only idealised scenarios of only sulphate aerosols have been used.

IPCC Second Assessment Report: Climate Change 1995 

Climate Change 1995, the IPCC Second Assessment Report (SAR), was finished in 1996. It was made in four parts:
 A synthesis to help interpret UNFCCC article 2.
 The Science of Climate Change (Working Group 1)
 Impacts, Adaptations and Mitigation of Climate Change (Working Group 2)
 Economic and Social Dimensions of Climate Change (Working Group 3)

Each of the working groups was made by its own working group, and each has a Summary for Policymakers (SPM) that is a list of agreements by governments. The Summary for Policy Makers of the Working Group 1 report says:

 Greenhouse gas has continued to increase
 CFC aerosols make radiation in the atmposphere
 Climate has changed over the past century (air temperature has increased by between 0.3 and 0.6 °C since the late 19th century; this is almost the same as the 1990 report).
 The evidence is that humans are changing the Earths climate (a lot of extra work was done since the 1990 report to see the difference between natural climate change and human changes, for example: the effects of aerosol gases)
 Climate is will continue to change in the future
 We cannot be sure of how much human effects will happen in future

Changing what the scientists say 

Three scientists involved in climate research believe that the IPCC reports do not accurately summarize the state of knowledge.

On December 20, 1995, Reuters news agency claimed a British scientist Keith Shine, one of IPCC's most important authors, talking about the Policymakers' Summary, said: "We produce a draft, and then the policymakers go through it line by line and change the way it is presented.... It's peculiar that they have the final say in what goes into a scientists' report". Keith Shine did not say what differences the changes make.

Frederick Seitz, a physicist of Rockefeller University, said the IPCC report was not good, writing "I have never witnessed a more disturbing corruption of the peer-review process than the events that led to this IPCC report". He opposed it in the Leipzig Declaration of S. Fred Singer's Science and Environmental Policy Project.

Professor Seitzs comments were opposed by the presidents of the American Meteorological Society and University Corporation for Atmospheric Research, who wrote about an effort by some people make it seem that humans had not changed the climate. Special insert .

S. Fred Singer said that :
 Chapter 8 was changed;
 Three important parts — the views of the authors, contributors, and reviewers —  should have been put in the Summary but they were deleted;

Benjamin D. Santer, Lead Author of Chapter 8 of 1995 IPCC Working Group 1 report, said :
 The purpose was to produce the best possible and most clear report of the science, and was under his full control.
 None of the changes were politically motivated.

Economic report 

The Second Assessment Report was the only one with a chapter on the economic effect of climate change. This part of the report was thought to be unfair because the value of life in poorer countries was less.

IPCC Supplementary Report: 1992 
The 1992 supplementary report was an update of the 1990 report, requested for the Framework Convention on Climate Change at the Earth Summit (United Nations Conference on Environment and Development) in Rio de Janeiro in 1992.

It did not make any important changes to the 1990 report. It claimed the prediction methods in the First Assessment Report, were now improved, but did not include aerosol or ozone changes.

IPCC First Assessment Report: 1990 
The IPCC first assessment report was completed in 1990, and used to make the United Nations Framework Convention on Climate Change (UNFCCC).

The Working Group 1 report says:
 We are certain there is a natural greenhouse effect...; humans are making the greenhouse effect stronger by releasing these gases: carbon dioxide (CO2), methane, CFC gases and nitrous oxide gas. These gases trap heat on the Earth.
 We calculate that: ...CO2 has been responsible for over half the stronger greenhouse effect; gases that stay in the air for a long time need to be used 60% less to stop making the greenhouse effect even stronger
 We predict: global temperature during the [21st] century will rise by 0.3 oC per decade (but possibly between 0.2 to 0.5 oC per decade); this is more warming than the past 10,000 years; Some other sudies predict that temperature will rise between 0.2 oC and 0.1 oC per decade.
 The predictions are not exact because we do not yet understand the effects of clouds, ice sheets, oceans and other important parts.
 We believe that world temperature has increased by 0.3 to 0.6 oC over the last 100 years...; This warming does not appear to be caused by humans but it is possible that humans have caused this warming. We will not be sure how much of the warming has been caused by humans for a decade or more.

IPCC structure 
The Chairperson of the IPCC is Rajendra K. Pachauri, elected in May 2002; before that Robert Watson headed the IPCC. The chairperson is helped by an elected Bureau including vice-chairpersons, Working Group co-chairpersons and a Secretariat (see below).

The IPCC Panel is made of people from governments and other groups.  Scientific experts are preferred. Meetings of the IPCC and IPCC Working Groups are held by members of governments. Non-Governmental and Intergovernmenta Organizations may be allowed to attend as observers. Meetings of the IPCC Bureau, workshops, experts and lead authors are by invitation only. 350 government officials and climate change experts visited the 2003 meeting. The meeting report  says there were 322 persons in attendance at meetings with about seven-eighths of visitors being from governments.

Major groups 

There are several major groups:
 IPCC Panel: Meets about once a year and controls the organization. The Panel is the IPCC corporate entity.
 Chairperson: Elected by the Panel.
 Secretariat: Controls all activities.  Supported by UNEP and WMO.
 Bureau: Elected by the Panel.  Chaired by the Chair.  30 members include IPCC Vice-Chairpersons, Co-Chairpersons and Vice-Chairpersons of Working Groups and Task Force.
 Working Groups: Each has two Co-Chairpersons, one from a richer country and one from a poorer country, and a technical support unit.
 Working Group 1: Studies the science of the climate system and climate change.
 Working Group 2: Studies the effects and dangers of human activity in relation to climate change and gives ideas for how to change human activity.
 Working Group 3: Studies options for limiting greenhouse gas and other ways to reduce climate change.
 Task Force on National Greenhouse Gas Inventories

The IPCC receives funding from UNEP, WMO, and its own Trust Fund which gets money from governments.

Contributors 
People from over 130 countries contributed to the IPCC Fourth Assessment Report over 6 years.  These people included more than 2500 scientific expert reviewers, more than 800 contributing authors, and more than 450 lead authors.

The Working Group 1 report of 2007 (including the summary for policy makers) included contributions by 600 authors from 40 countries, over 620 expert reviewers, a large number of government reviewers, and representatives from 113 governments.

Activities 
The IPCC activities are controlled by the WMO Executive Council and UNEP Governing Council to support the UN Framework Convention on Climate Change.

In April 2006, the IPCC released the IPCC Fourth Assessment Report or AR4. Reports of the workshops held so far are available at the IPCC website.
 Working Group 1  :
 Report was finished during February of 2007  .
 By May 2005, there had been 3 AR4 meetings, the only public information was the meeting locations, an author list, one invitation, one agenda, and one list of presentation titles.
 By December 2006, governments were reviewing the Summary for Policy Makers.
 Working Group 2  :
 Report was finished in mid-2007.
 In May 2005, there had been 2 AR4 meetings, with no public information released.
 One meeting with Working Group 3 workers had taken place, with a published report.
 Working Group 3  :
 Report was to be finished in mid-2007.
 In May 2005, there had been 1 AR4 meeting, with no public information released.

The AR4 Synthesis Report (SYR) was finalized in November 2007. Documentation on the meetings for the AR4 are available  , the outlines for the Working Group 1 report  and a provisional author list .

The IPCC also supports other activities, such as the Data Distribution Centre Welcome to the IPCC Data Distribution Centre and the National Greenhouse Gas Inventories Programme IPCC - Task Force on National Greenhouse Gas Inventories. This involves estimating greenhouse gas based on the levels of fuel used, industrial production and so on.

The IPCC also answers questions from the UNFCCC Subsidiary Body for Scientific and Technological Advice (SBSTA).

Publications

Preparation of the reports 
The IPCC reports are a collection of peer reviewed and published science.  Each IPCC report explains improvements to the previous report and also explains where more research is needed.

There are usually three stages in the review :
 Expert review (6–8 weeks)
 Government/expert review
 Government review of: Summaries for Policymakers, Overview Chapters, and Synthesis Report
Review comments are open to the public for at least five years.

There are several ways to agree what goes into the reports:
 approval: Line by line agreement.
 Working Group Summaries for Policymakers are approved by their Working Groups.
 Synthesis Report Summary for Policymakers is approved by Panel.
 adoption: Section by section (and not line by line) agreement.
 Panel adopts Overview Chapters of Methodology Reports.
 Panel adopts IPCC Synthesis Report.
 acceptance: No line by line discussion. Most people agree.
 Working Groups accept their reports.
 Task Force Reports are accepted by the Panel.
 Working Group Summaries for Policymakers are accepted by the Panel after group approval.

The Panel controls what the IPCC agrees on to meet standards. The Panel's approval process has been criticized for changing what the experts put in the Reports.

Authors 
Each chapter has a lot of authors who are responsible for writing and editing the material. A chapter usually has two "Coordinating" Lead Authors who control what words go in their chapter, ten to fifteen Lead Authors, and a larger number of Contributing Authors. The Lead Authors put together the work of the other authors and report to the Working Group chairs. Lead Authors write sections of chapters. Contributing Authors prepare text, graphs and data.

Authors are chosen from a list of researchers prepared by governments, other important groups, the Working Group/Task Force Bureaux, and other experts (, 4.2.1,2). The group of Coordinating Lead Authors and Lead Authors for a section or chapter of a Report is expected to have many different views and to have people from different parts of the world.

Nobel Peace Prize 2007 
In December 2007, the IPCC was awarded The Nobel Peace Prize 2007 "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change."  The award is shared with Former U.S. Vice-President Al Gore for his work on climate change and the documentary An Inconvenient Truth.

Criticism of IPCC

Christopher Landsea resignation 
In January 2005 Christopher Landsea resigned from work on the IPCC AR4, saying that it was "both being motivated by pre-conceived agendas and being scientifically unsound" because of Kevin Trenberth of the National Center for Atmospheric Research's idea that global warming was contributing to recent hurricane activity.  Roger A. Pielke who published Landsea's letter writes: "How anyone can deny that political factors were everpresent in the negotiations isn't paying attention", but says that "Despite the pressures, on tropical cyclones they figured out a way to maintain consistency with the actual balance of opinion(s) in the community of relevant experts." He continues "So there might be a human contribution (and presumably this is just to the observed upwards trends observed in some basins, and not to downward trends observed in others, but this is unclear) but the human contribution itself has not been quantitatively assessed, yet the experts, using their judgment, expect it to be there. In plain English this is what is called a 'hypothesis' and not a 'conclusion.' And it is a fair representation of the issue."

"Hockey stick" graph 

The IPCC Third Assessment Report showed a graph labeled "Millennial Northern Hemisphere temperature reconstruction" from a paper by Mann, Bradley and Hughes (MBH98) often called the "Hockey Stick Graph". This graph was different to the IPCC First assessment report which showed global temperature for the past 1000 years, and higher temperatures during the Medieval Warm Period. The graph was thought to show that temperatures between 1000 and 1900 were very different. This was criticized in an article by Stephen McIntyre and Ross McKitrick. In a 2006 letter to Nature, Bradley, Hughes and Mann claimed the original article had said that they could not be exact.

Risks 
Some critics say the IPCC reports underestimate dangers, understate risks, and report only the lowest risks.

On February 1, 2007, the night before publication of IPCCs report on climate, a study was published saying that temperatures and sea levels have been rising at or above the speed the IPCC reported in 2001.  The study compared IPCC 2001 predictions of temperature and sea level change with what actually happened.  Over the six years, the actual temperature rise was near the top end of the range given by IPCC's 2001 prediction and the actual rise was more than the top of the range the IPCC predicted.

An example of scientific research which has indicated that predictions by the IPCC have uderstated risks is a study on rises in sea levels.

Political influence on the IPCC has been shown by the release of a memo by ExxonMobil to the Bush administration, and its effects on the IPCCs leadership. The Bush administration, at the request of ExxonMobil, wanted rid of Robert Watson, a climate scientist and IPCC chairperson, and to have him replaced by Pachauri, who was seen at the time as more friendly to industry.

IPCC process 

In 2005, the UK House of Lords Select Committee on Economic Affairs produced a report on the economics of climate change. It commented on the IPCC process:

"We have some concerns about the objectivity of the IPCC process, with some of its emissions scenarios and summary documentation apparently influenced by political considerations.  There are significant doubts about some aspects of the IPCCs emissions scenario exercise, in particular, the high emissions scenarios.  The Government should press the IPCC to change their approach. There are some positive aspects to global warming and these appear to have been played down in the IPCC reports; the Government should press the IPCC to reflect in a more balanced way the costs and benefits of climate change.  The Government should press the IPCC for better estimates of the monetary costs of global warming damage and for explicit monetary comparisons between the costs of measures to control warming and their benefits. Since warming will continue, regardless of action now, due to the lengthy time lags.

Related pages
 Global warming

Notes and references

Other websites 
 The IPCC website
 IPCC Organisation 
 
 IPCC publications 
 IPCC AR4 WG1 Report Available for Purchase 
 Summaries for Policymakers (SPMs) of the IPCC Fourth Assessment Report:
 ,
 
 
 A summary of the Fourth Assessment Report SPMs by GreenFacts.
 IPCC article  at the Encyclopedia of Earth - General overview of the IPCC
 Climate Change - What Is the IPCC by Jean-Marc Jancovici
 Climate Change Freeview Video Interview 2006 - Sherwood Rowland, Nobel Laureate (1995) for work on ozone depletion discusses climate change. Provided by the Vega Science Trust.
 «UN scientist backs '350' target for CO2 reduction», AFP, August 25 2009

1988 establishments
International environmental organizations
United Nations specialized agencies
Climate change