Piece By Piece – The AGW Side

The questions in the public sphere — which is my natural subject matter — are whether we’re facing a meltdown or whether it’s all a big hoax. I’m not claiming these are the right questions — I’m claiming these are the questions being debated. You may rightfully think they are false alternatives but the public sphere never was one for avoiding logical fallacies. Recently, I read about James Hansen’s trip to Copenhagen and how he had to have a police escort because of death threats.  Recently as well, Steven Mosher has informed us that Steven McIntyre’s safety has been in question.

I’m interested in how we got to this state of things. How is it that the questions are either “Are Deniers Misrepresenting The Science to Delay Action?” or “Are Scientific Fraudsters Perpetrating a Hoax?”

A good place to start is with what each side is saying: What is the position and arguments and evidence produced in the AGW dominant scientific paradigm? What is the position and arguments and evidence of the critics, whether they be skeptics, contrarians or denialists?

I’m going to try taking it one step at a time. A first step is to review the most recent Assessment Report of the IPCC to get an idea of what the IPCC says about the state of the climate in 2007 and then review what the critics say about it.

First, what is the IPCC? (note: all the following is adapted from the IPCC website)

ETA: Tomorrow, besides a post on the modeling forecasts, I’m going to add a post on the origins of the IPCC, which I believe is key to understanding the politicization of climate science. But I want to start with a general overview of what the main debates really are about by laying part of the framework. Since AGW is the dominant scientific paradigm, it is the focal point for debate and analysis. An analysis of the origins of the IPCC and the “discovery of global warming” will then set the stage for the politicization of the science and the development of the battle lines.

  • The IPCC was established by the UNEP and WMO to “provide the world with a clear scientific view on the current state of climate change and its potential environmental and socio-economic consequences.”
  • The Working Group selects from a list of nominations received from governments and participating organizations the IPCC authors, contributors, reviewers and other experts who will produce the assessment reports.
  • The work on the assessment reports is voluntary and the authors etc. are supposed to reflect “a range of views, expertise and geographical background”.
  • The IPCC “does not conduct any research nor does it monitor climate related data or parameters.”  The authors are expected to “assesses the most recent scientific, technical and socio-economic information produced worldwide relevant to the understanding of climate change.”
  • Each chapter in the assessment report has two coordinating lead authors (CLAs), who are responsible for coordinating the chapter, while lead authors (LAs)create the content. There are also contributing authors (CAs) who may offer specific technical information covered in the chapters.
  • According to the IPCC, there is a multi-stage review process during which scientists and governments review the documents. Hundreds of scientists and government officials review the documents for accuracy and soundness of the information contained within it. Review editors take all comments into account and review comments are kept archived for a period of 5 years.
  • Funding: “The IPCC is funded by regular contributions from its parents’organizations WMO and UNEP, the UNFCCC and voluntary contributions by its member countries.”

Next, onto the 2007 Synthesis Report, which includes the following in the Introduction:

Where uncertainty is assessed qualitatively, it is characterised by providing a relative sense of the amount and quality of evidence (that is, information from theory, observations or models indicating whether a belief or proposition is true or valid) and the degree of agreement (that is,the level of concurrence in the literature on a particular finding). This approach is used by WG III through a series of self-explanatory terms such as: high agreement, much evidence; high agreement, medium evidence; medium agreement, medium evidence; etc.

Where uncertainty is assessed more quantitatively using expert judgement of the correctness of underlying data, models or analyses, then the following scale of confidence levels is used to express the assessed chance of a finding being correct: very high confidence at least 9 out of 10; high confidence about 8 out of 10; medium confidence about 5 out of 10; low confidence about 2 out of 10; and very low confidence less than 1 out of 10. (27)

This is the guide to how the IPCC reports assess uncertainty. This is important to determine if it is under- or over-representing the data.

What does the report claim about the science of climate change?

  1. Warming is unequivocal and is evident from observations of increases in global air and ocean temperatures, widespread melting of snow and ice and rising global average sea levels.
  2. 11 of the last 12 years (1995-2006) were the hottest on record for the instrumental record of global average temperature;
  3. The 100 year linear trend is 0.73 deg C (0.56-0.92), which is larger than in the AR4  of 0.6 deg C (04-0.8), The linear trend for the last 5o years (1956-2005) is 0.13 deg C (0.10- 0.16), which is twice that of 1906 – 2005.
  4. Average arctic temperatures have increased the most, at twice that of the average rate of the last 100 years.
  5. Land regions have warmed faster than oceans. Oceans have taken up 80% of the heat added to the system.
  6. Lower to mid troposphere temperatures show similar rates of warming to the surface temperatures.
  7. Global average sea levels have risen by an average of 3.1 mm (2.4 – 3.8) per year from 1993 to 2003 and 1.8 mm (1.3-2.3) per year from 1961 to 2003.
  8. Since 1978, annual average Arctic sea ice extent has shrunk by 2.7% per decade (2.1 – 3.3) with summer decreases of 7.4% (5.0 – 9.8). Maximum areal extent of seasonally frozen ground has decreased by about 7% in the Northern Hemisphere since 1900. Temperatures in the top of the Arctic permafrost have generally increased by up to 3 deg C since 1980s.


From the chapter on Causes of Change:

  • Changes in the atmospheric concentrations of GHGs and aerosols, land cover and solar radiation alter the energy balance of the climate system and are drivers of climate change. They affect the absorption, scattering and emission of radiation within the atmosphere and at the Earth’s surface. The resulting positive or negative changes in energy balance due to these factors are expressed as radiative forcing, which is used to compare warming or cooling influences on global climate. (37)
  • The atmospheric concentrations of CO2 and CH4 in 2005 exceeded by far the natural range over the last 650,000 years.  Global increases in CO2 concentrations are due primarily to fossil fuel use, with land-use change providing another significant but smaller contribution.(37)
  • There is very high confidence that the global average net effect of human activities since 1750 has been one of warming, with a radiative forcing of +1.6 [+0.6 to +2.4] W/m2. (37)
  • The combined radiative forcing due to increases in CO2, CH4 and NO is +2.3 [+2.1 to +2.5] W/m2 and its rate of increase during industrial era is very likely to have been unprecedented in more than 10,000 years (Figures 2.3 and 2.4). The CO2 radiative forcing increased by 20% from 1995 to 2005, the largest change for any decade in at least the last 200 years.(37-38)
  • Anthropogenic contributions to aerosols (primarily sulphate, organic carbon, black carbon, nitrate and dust) together produce a cooling effect, with a total direct radiative forcing of -0.5 [-0.9 to -0.1] W/m2 and an indirect cloud albedo forcing of -0.7 [-1.8 to -0.3] W/m2. Aerosols also influence precipitation.(38)
  • In comparison, changes in solar irradiance since 1750 are estimated to have caused a small radiative forcing of +0.12 [+0.06 to +0.30] W/m2, which is less than half the estimate given in the TAR. (38)
  • The equilibrium climate sensitivity is a measure of the climate system response to sustained radiative forcing. It is defined as the equilibrium global average surface warming following a doubling of CO2 concentration. Progress since the TAR enables an assessment that climate sensitivity is likely to be in the range of 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C. Values substantially higher than 4.5°C cannot be excluded, but agreement of models with observations is not as good for those values. (38)
  • Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations. This is an advance since the TAR’s conclusion that “most of the observed warming over the last 50 years is likely to have been due to the increase in GHG concentrations” (39)
  • is likely that increases in GHG concentrations alone would have caused more warming than observed because volcanic and anthropogenic aerosols have offset some warming that would otherwise have taken place. (39)

I’ll deal with forecasts in a separate post but for now, I wanted to lay out the AGW side and then examine the critics and their response.

This is probably boring material to most readers, but I want to open it up for comments on the main points and issues. Since many of the readers here are skeptics, tips on good pages to read for the critical / skeptic take on the 2007 Synthesis Report are appreciated.

What are the main issues with the report’s findings?  What are things to consider?

I have a few issues having to do with the process itself and how the participants are selected and how the document is constructed and vetted, but that’s all for now.

The next post will be on SRES projections and then the Reviewer Comments and what they contain and how they were dealt with.


About Policy Lass

Exploring skeptic tales.

14 Responses to “Piece By Piece – The AGW Side”

  1. The IPCC has been criticized both for a faulty process (having lead authors in a position to protect their main findings against criticism from other climate scientists) and for its conclusions. It is only fair to point out some people think the IPCC is too conservative in its projections of future warming, but I take the other side. In addition to claims IPCC bias exaggerates the warming trend, the IPCC also blames CO2 to the near exclusion of other anthropogenic causes. Roger Pielke has documented the role of land use/land cover changes in peer reviewed papers, but the IPCC ignores them.

    Here are a few links to criticism of the IPCC:



    Climategate should dramatically change the next IPCC report, AR5. The paleoclimate chapter should be very different because the CRU emails show Keith Briffa thought the MWP was as warm as today, even though the IPCC chapter he authored did not say that. I think the next one will. Also, the Russians have pointed out how the CRU cherrypicked Russian temp data. I expect a new temp record, and more reliable one, will be available before AR5. See what Warwick Hughes has to say about the Russian data. http://www.warwickhughes.com/blog/?p=373

    Finally, a number of very important papers were published after the deadline for AR4. These include the climate sensitivity estimate published by Stephen Schwartz of Brookhaven National Lab, a series of papers by Petr Chylek of Los Alamos National Lab, a paper by Roy Spencer on a new observation of a negative feedback over the tropics and many other important papers which show global warming is not going to be catastrophic.

    AR4 was a very imperfect assessment of climate science. It underestimated the role of natural climate variability, neglected warming from land use/land cover changes, and was based on data which had been fudged by the CRU in the areas of paleoclimate and surface temperature data. More importantly, a great deal of research since 2007 shows the IPCC conclusions overestimated climate sensitivity to CO2.

    • Thanks Ron.

      I’m officially off my vacation today so I’m back to work and won’t be responding to anything until evening, but I will look into your links and suggestions.

  2. Crap susann you cant even get the history complete or right

    Go back to the WMO conference in 1979 and look at the conclusions there. That was the starting point which FRAMED the entire formation, prior to any investigation. The assumptions going in were A) the world had warmed as the result of human action GHGs,
    that global action was required, that the next century would be the warmest in history.

    THAT meeting set the framework. duh.

    Nice too how you cut out some elements:

    The role of the IPCC is to assess on a comprehensive, objective, open and transparent basis the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation

    BTW, interests in the SRES was what got me into this whole debate.

    • Mosh: you might be interested in this re the formation of the IPCC:


      It’s from the Environmental Defense Fund. Replete with a description of how he believes they duped the Reagan Administration.

      And you are correct about 1979. This whole thing started out as a hunch based on very flimsy evidence and has since snowballed into the monstrosity we face today which to this non-scientist seems based on very selective evidence.

      • Crap. That part of the book is already done. Lemme see what I can do.

        Its funny, I go to the IPCC literature and right away go back to 1979 and see the assumptions that drove the formation. Susann cant see the assumptions that frame and guide the subsequent science. Perhaps it has to do with my training in arguing for various sides of an issue or doing threat analysis where you are forced to see an issue from all sides, to get inside the skin of either the red side or blue side and think like the enemy.
        I don’t fault her for lacking this skill, I just note it.

      • Ok, I’ve got the 85 meeting covered in the book and the need for global action.

        Of course as a believer in getting our independence from foreign oil , that is as a support of nuclear I can only look at all this effort expended toward global action ( requiring global action is the strongest form of delay on climate issues ) and wonder how much closer the US would be to an oil free/ coal free economony if we would have started down the path to nuclear more forcefully in 1979 when we knew that GHGs were going to be a problem. The next right action usually trumps the centrally planned action. Oh well.

        Those enviromentalist were just peddling doubt about nuclear power. look at how they delayed us from saving the planet.

  3. Susann,

    Reviewing the IPCC and AR4 is an excellent place to start.
    I have a large number of detailed criticisms of AR4 on my site.
    In particular, in relation to the points 1-9 that you mention above:

    3 – the increased 100-year trend is due to two things: (a) A sharp drop in global temperature in the early 1900s, hence lower starting point. (b) warming ‘inflation’ by using different datasets in AR4 vs TAR. If you use the same dataset (Hadcrut3) you get 0.66 and 0.74 (not 0.6 and 0.74)

    3 – comparing 50 year trends with 100 year trends is just ridiculous. Obviously with any fluctuating signal, longer trends are going to be lower than shorter ones. If you compare the first 50 yrs with the whole century you get the opposite of the IPCC result! This daft comparison would not have got through the review – it was inserted into the final draft after review.

    4, 8 Let’s not mention Antarctica, where ice extent has increased.

    7 – here we see the same tricks as in 3: compare a short period with a long period, and compare one data set (tide gauges) with another (satellite altimetry).

  4. The simple English version of your long intro piece

    “We are the UN, we are here to help you.”

    If you trust the UN or any large taxpayer funded bureaucracy to have your est interests at heart then you’ll believe their message.

    If you believe the UN or any large taxpayer funded bureaucracy has as is prime directive to a) survive and b) expand its power, you’ll believe the message that AGW is a crock of hooey.

    Even a very brief examination of the IPCC operations and the latter option is the only logical choice. The Climategate letters are only the latest in a long series of scientific corruption by the IPCC leadership.

    But hey, it is free country still and you can believe what you want.

  5. PaulM, linked to your website. I love the hypocrisy. You accuse the IPCC od making misrepresentations, then you go and make misrepresentations yourself to refute their points!

    An example, you claim that the Antarctic ice sheet is thickening. Hmmm, have you read the recent papers by Velicogna and Chen? They found that:

    “The GRACE assessment of Velicogna (2009) indicates that, like Greenland, the rate of mass loss from the Antarctic ice sheet is accelerating, increasing from 104 Gt per year for 2002-2006 to 246 Gt per year for 2006-2009”. One gigaton (Gt)
    is equivalent to a cube of water 1 kilometre wide, tall, and deep.

    A new study Chen et al. (2009, Nature Geoscience) has found that the east Antarctic ice shelf, which was though to be stable, is also losing ice. They state “we estimate a total loss of 190 Gt yr-1, with 132 Gt yr-1 coming from West Antarctica. However, in contrast with previous GRACE estimates, our data suggest that East Antarctica is losing mass, mostly in coastal regions, at a rate of -57 Gt yr-1, apparently caused by increased ice loss since the year 2006.”

    That was just one example, how about another fallacious claim that tropical cyclones are not increasing. You are oblivious to the work on Kerry Emmanuel one of the leading experts in the world on tropical cyclones.

    Emanuel (2005, Nature) calculated a power dissipation index (PDI) this index to quantify the threat of tropical cyclones. The PDI is a better indicator of tropical cyclone threat than storm frequency or intensity. Emanuel’s research showed that the PDI has nearly doubled in the past 30 years. Similarly, Webster et al. (2005, Science) analyzed satellite data from the past 35 years and found a “large increase in the number and proportion of hurricanes reaching category 4 and 5. The largest increase occurred in the N. Pacific, Indian and Southwest Pacific Oceans.” Hoyos et al. (2006, Science) came to a similar conclusion.

    I’m sorry your intentions with that page are less than honorable and while they may enforce Cram’s bias and provide fodder for the layperson who has doubts, your claims do not stand up to scrutiny.

    • The problem with pulling one fact out of the mix and holding it up as proof of something larger is that when the “fact” is considered within whole, the meaning of that fact changes.

      Forex, some skeptics point to increased snowfall in the Antarctic ice sheet as refuting the claim that there is any warming. However, the theory, as I understand it, and models show, that warming ocean temperatures will lead to more precipitation, but also ice loss on the continent borders due to warmer water, etc. So in fact, it could be argued that the increase in snow mass in the interior is actually support for AGW…

  6. Susann,
    If you are truly interested in finding good skeptical science papers, and I’m not convinced at the moment, here is one for you to read.

    It was written by Nicholas Scarfetta, a physicist at Duke University, and published in Journal of Atmospheric and SolarTerrestrial Physics in Dec. 2009.


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