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Presentation: climate change and the precautionary principle

September 20th, 2006

I’ve uploaded my presentation on climate change and the precautionary principle, which I gave at City Hall on Monday night. It’s here in
Powerpoint (4.9Mb)
or
PDF (1.9MB)
formats.

Finally, here’s a version Zipped Mac Keynote (4.8Mb).

Thanks to everyone who’s given helpful suggestions for the upload, and noted problems with the download.

Sorry for the accidental temporary disappearance of this post. I somehow set it to “private”, which meant that it appeared for me, but for no-one else

Categories: Environment Tags:
  1. September 20th, 2006 at 13:35 | #1

    The PDF link is wrong, but it can be found by changing the suffix on the ppt link.

  2. September 20th, 2006 at 13:40 | #2

    John, try zipping the Keynote file and uploading the zip file. I think WP might be complaining because a Keynote file is actually a folder – MacOS X just treats it like a file.

  3. econwit
    September 20th, 2006 at 15:27 | #3

    “Observed increase in global temperature 0.5 degrees in C20, mostly after 1970�

    Aberrations in global temperatures of more than this magnitude over longer time frames are a common occurrence. This temperature change could be deemed “normal�. Predictions based on temperature movements since 1970 might be found to be inaccurate.

    I read somewhere recently that research being conducted at Newcastle University (Aust) had discovered that the formations in limestone caves, which occur over many thousands of years, provided very accurate long term records of rainfall and air temperatures over the periods of their formation. Although the research was in its preliminary stages they seem to imply that a movement in average temperatures up or down of a few degrees over time was not unusual.

    Does anyone know somebody up at The University Of Newcastle’s geology department that can give us the facts on temperature movements?

  4. chrisl
    September 20th, 2006 at 16:55 | #4

    There was a particularly relevant comment from a poster at another site,commenting about the U.K….”AGW is the last respectable argument for large scale government intervention in the economy. It is no surprise that economists would develop an interest in AGW.”

  5. rog
    September 20th, 2006 at 17:08 | #5

    PFD link

    http://johnquiggin.com/wp-content/uploads/2006/09/climatechange0609.pdf

    The PPT is a big download for those still struggling with the govt owned TLS..

  6. September 21st, 2006 at 08:35 | #6

    econowit – “This temperature change could be deemed “normalâ€?. Predictions based on temperature movements since 1970 might be found to be inaccurate.”

    Sure if there was nothing else going on. However since greenhouse gases are increasing and these have been proven to trap heat then it stands to reason that THIS recent warming is caused by these greenhouse gases and is not ‘natural’. To assume that it is natural is to ignore a large body of physical evidence.

    ChrisL – “â€?AGW is the last respectable argument for large scale government intervention in the economy. It is no surprise that economists would develop an interest in AGW.â€?”

    Sure so governments invented AGW just so they could intervene. I thought I was the conspiracy theorist.

  7. jquiggin
    September 21st, 2006 at 08:42 | #7

    And of course, ChrisL’s minor premise is wrong – the failure of vigorous attempts by Thatcher, Roger Douglas and others to make substantial reductions in the ratio of public expenditure to GDP suggests that, at least as far as the political process is concerned, there is no shortage of adequate rationales for government intervention. In fact the reverse is the truth – governments everywhere find more demands than they can deliver. This is true even in the US, where the weaker demand for social services is offset by a higher demand for military action.

  8. Ian Castles
    September 21st, 2006 at 11:08 | #8

    I would be interested to have comments from experts on the following line of reasoning:

    (1) According to Table II-4 of the IPCC’s “Climate Change 2001: The Scientific Basis� (available at http://www.grida.no/climate/ipcc_tar/wg1/552.htm ), the model average surface air temperature change to 2030 is 0.18ºC HIGHER under the A1T scenario than under the A1B and A1FI scenarios, notwithstanding that the total projected additional forcing from emissions of CO2, CH4, N2O and tropospheric O3 is LOWER under the A1T scenario than under the other two scenarios (see the preceding tables in Appendix II).

    (2) Thus the greater warming under A1T is entirely attributable to the modelled impact on temperatures of the projected reduction in sulphur emissions, and hence in the atmospheric concentration of sulphate aerosols, under that scenario (see the “Note� to SRES Table II.2.7: “Global burden [of sulphate aerosols] is scaled to emissions: 0.52 Tg burden for 69.0 TgS/yr emissions).

    (3) But the available evidence suggests that the reduction in sulphur emissions projected under the A1T scenario between 2000 and 2030 had ALREADY OCCURRED between 1990 and 2000. According to van Vuuren and O’Neill, 2006, “The Consistency of IPCC’s SRES Scenarios to Recent Literature and Recent Projections�, Climatic Change, March 2006:

    “In SRES, worldwide sulfur emissions were assumed to decline by 3% in the 1990-2000 period… Studies that estimate actual trends in that period now find that worldwide emissions actually decreased by a much larger amount (around 20%)â€? (p. 39). Three studies showing this result are cited as sources (see Table VI on p. 38).

    (4) The observed increase in global mean surface temperatures since 1990 is of the order of 0.3ºC.

    (5) Thus the observed increase in temperature in the past decade-and-a-half is fully explained by the reduction in (negative) forcing from sulphate aerosols, if the models are right. If there has also been positive forcing from emissions of GHGs, this must have been offset by other factors.

    (7) Or the models are wrong.

  9. econwit
    September 21st, 2006 at 11:11 | #9

    “the failure of vigorous attempts by Thatcher, Roger Douglas and others to make substantial reductions in the ratio of public expenditure to GDP suggests that�:
    The ‘revenue lobby’ (comprising the ATO, the Treasury and their allies in politics, ACADEMIA, the media and the welfare industry) is alive and well.

    This is defiantly a case of the pot calling the kettle black!
    “at least as far as the political process is concerned, there is no shortage of adequate rationales for government intervention. In fact the reverse is the truth – governments everywhere find more demands than they can deliver.â€? -That doesn’t make it right Mr Quiggin.

    “In fact� :
    “An effectively functioning society is founded upon educated individuals who would then act to restrain the excesses of government or the reckless actions of a mass of people�.

    And you put yourself forward as an “educated individual�.

    Ender:
    It could be getting hotter I don’t know –it seems like it. All I am saying is there could be some scientists (not economists) up in Newcastle with some accurate figures. I prefer scientific evidence to economic speculation.

  10. observa
    September 21st, 2006 at 11:16 | #10

    I warned all the 20/20 hindsight buffs about their confected outrage and concomitant enthusiasm for suing James Hardie and the tobacco companies for long term epidemiological risk. Here is the slippery slope you were motoring down
    http://www.news.com.au/story/0,10117,20450221-401,00.html?from=public_rss
    Or should I say jogging or cycling down soon?

  11. observa
    September 21st, 2006 at 11:23 | #11

    My consistent take by the way is- as long as ‘we’ via our elected govt allow a product or sevice to be sold legally, there is no legal liability for deleterious, epidemiological consequences to any of us. Otherwise you could theoretically have uni students being sued for being console operators at servos.

  12. observa
    September 21st, 2006 at 11:35 | #12

    Yes, I recall a recent news report that Finlaysons was setting up a special ‘environmental’ area for the future http://www.finlaysons.com.au/practice-environment.html
    Seems like they weren’t exactly out there with Nostardamus on that one.

  13. Aidan
    September 21st, 2006 at 11:41 | #13

    …or tobacco companies being sued for making cigarettes?

  14. Ian Castles
    September 21st, 2006 at 11:52 | #14

    Further to my statement above that the model average temperature change to 2030 is nearly 0.2ºC higher under the IPCC’s A1T scenario than under the other two A1 illustrative scenarios, please see also the IPCC’s Figure 9-15(a), which shows the modelled temperature change over this period for each of the seven models individually ( http://www.grida.no/climate/ipcc_tar/wg1/fig9-15.htm ).

    Note that all of the models are similar in that the A1T temperature change (represented by red squares) is about 0.2ºC higher than the temperature change under A1B (represented by red circles) and A1FI (represented by red triangles).

  15. observa
    September 21st, 2006 at 12:18 | #15

    “…..or tobacco companies being sued for making cigarettes? ”
    Well they were previously sued for making cigarettes without warnings on them. Perhaps that’s the answer for all private enterprise nowadays Aidan, from electricity generators, carmakers, coalminers, petrol companies, etc,etc. Place such long and tedious cover all warnings and statements of possible guilt on your products, so as to become almost fatuous. A bit like the fine print with drugs from drug companies these days.

    You really have to wonder what California hopes to gain by suing car manufacturers. What’s next on their list of things to sue? Their petrol, power, bus, train companies, etc?? Will they only sue the American based companies they can legally get their hands on and import all the nasty sued stuff from overseas, in particular China? Will that make these public service retards feel good? The ultimate lotus eaters, eating their own entrails. Sheesh!

  16. September 21st, 2006 at 13:16 | #16

    econowit – “It could be getting hotter I don’t know –it seems like it. All I am saying is there could be some scientists (not economists) up in Newcastle with some accurate figures. I prefer scientific evidence to economic speculation.”

    Yes there maybe however there are hundreds of scientists all over the world with scientific evidence that shows the climate is warming. Are they all wrong? Also all global warming and cooling are not always caused by the same things. Past warming/cooling is no proof that recent warming is not caused by humans.

  17. September 21st, 2006 at 13:42 | #17

    Ian – the OBSERVED warming is about 0.6° which would have been much higher without aerosol cooling. Also there is a time lag with warming from the heat sink of the oceans. We have not seen all the warming yet.

  18. econwit
    September 21st, 2006 at 14:01 | #18

    Ender

    “There are hundreds of scientists all over the world with scientific evidence that shows the climate is warming. Are they all wrong?� Warming in comparison to what?

    My understanding is that it is very difficult to get accurate records of temperature readings more than 150 years old.

    Some Geologists at Newcastle University might have found a way to overcome this problem and provide us with accurate temperature readings going back for many thousands of years. They do this by analysing the formations of limestone in caves. They apparently leave an accurate annual record of average rainfall and temperature.

    If this method proves to be more accurate than other methods, then the answer to your question “are they all wrong?� would be yes.

  19. econwit
    September 21st, 2006 at 14:08 | #19

    How do you define “normal�?, if you don’t know the long term fluctuation in temperatures.

    Maybe, even a few thousand years of temperature knowlege might not be long term enough.

  20. Ian Castles
    September 21st, 2006 at 14:18 | #20

    No Ender, I’m talking about the observed warming since 1990 (the base year for all the IPCC projections). That has been at most 0.3°, which is in line with the IPCC’s projections of warming during this period as shown in Table II-4.

    These projections assumed that there would be little change in sulphur emissions between 1990 and 2000. The point is that it now appears that there was a LARGE decrease in sulphur emissions in that decade. According to the models, that leads to WARMING.

    You say that the warming that has occurred would have been much higher without aerosol cooling. But that masking of the warming would have to have occurred before 1990, because since then the decline in aerosols would have been ADDING to the temperature increase which was projected as a result of GHG emissions and the lagged warming from heat sink of the oceans. So my question is: Why has the observed temperature increase been so small?

  21. September 21st, 2006 at 14:43 | #21

    econowit – “If this method proves to be more accurate than other methods, then the answer to your question “are they all wrong?â€? would be yes.”

    Even if they do provide accurate data, which is a good thing BTW, and it proves there has been warming and cooling in the past this does not mean that recent warming is not happening. The multi proxy studies have shown that recent warming is inprecendented. This new proxy will add to the accuracy of the other proxies however I will be very suprised if it completely disagrees with them.

  22. Econoclast
    September 21st, 2006 at 14:43 | #22

    One of the key points for me from the Prof’s presentation about the precautionary principle is that in the case of global warming we can’t know whether the warming is man made or not, because yes it has happened before without our help.

    But the facts are (from my limited reading) that CO2 has the warming properties it has, and in the past, fluctuations in its levels have been associated with warming (the carbon cycle). And the biggest indisputable fact – we are pumping ****loads of it into the atmospere! More than the earth has ever had done to it before.

    So, the precautionary principle says, what’s the cost erring on the side of safety? Pretty significant, but not that bad (just bad for vested interests). What’s the option value we gain by erring? Anything up to and including avoiding anihilation.

  23. September 21st, 2006 at 15:07 | #23

    Ian – “So my question is: Why has the observed temperature increase been so small?”

    I don’t know – have you asked this on RC? My take on it would be there is no way of knowing, due to uncertainties, that the decrease aerosol forcing is sufficient to have decreased cooling enough to produce a 0.3° temperature rise. Also Gavin from RC provided this from a post on aerosols:
    http://www.realclimate.org/index.php/archives/2006/04/global-dimming-and-climate-models/#more-292

    “Why does the NOVA documentary (and this review) focus on “Dimming the Sun”, when according to your Global Dimming may have a brighter future radiation at the surface has been brightening since 1990? And given that the rise in global temperature has been fairly steady for the past few decades, what (if anything) does this dimming / brightening cycle tell us about climate sensitivity?

    [Response: The post 1990 'brightening' is less certain than the longer term dimming and is more fraught with data quality and length of time series issues. It may also be restricted to European and US stations, rather than Asian ones. We'll see though once the data series get longer. Does this mean anything for 'climate sensitivity'? In the specific sense of the climate response to 2xCO2, no it doesn't. In the more general sense of how is the planet reacting to all the changes we've made, then yes, the surface energy budget is a big (but complicated) part of that. - gavin]”

    So it is quite likely that the brightening does not account for the 0.3° of recent warming.

    For more reading on this:
    http://www.realclimate.org/index.php/archives/2006/02/an-aerosol-tour-de-forcing/

  24. Ian Castles
    September 21st, 2006 at 16:34 | #24

    Ender, Thanks for the link to the posting on RC and for the material provided by Gavin.

    The RC posting concludes: “Regardless of the absolute amount of the forcing, future reductions in aerosol emissions will be a positive forcing, amplifying the warming effects of increasing greenhouse gases.�

    The Summary for Policymakers of the IPCC TAR states that: “Temperature increases are projected to be greater than those in the SAR, which were about 1.0 to 3.5°C based on the six IS92 scenarios. The higher projected temperatures and the wider range are due primarily to the lower projected sulphur dioxide emissions in the SRES scenarios relative to the IS92 scenarios� (emphasis added).

    We keep getting told that every line in the IPCC SPMs is carefully considered. If an increase from 3.5 to 5.8 in the top of the projected temperature range is due primarily to lower projected sulphur dioxide emissions, then it follows as a matter of simple arithmetic that governments and their expert advisers believed that an increase of at least 1.15 in global mean temperatures was attributable to reductions in projected sulphur dioxide emissions. Yet in all scenarios these emissions were projected to be at least 30% of their 1990 levels in 2100.

    So the modelled increases in temperature between 1990 and 2000 would have been substantially greater if the modellers had known that sulphur emissions had already decreased by 20% before the IPCC climate projections were published.

    I take Gavin’s point that the post-1990 ‘brightening’ is less certain than the longer term dimming. But the paper that I quoted named three independent estimates, all of which came to a similar conclusion. And it would seem that there must be an upper limit to the ‘brightening’. because sulphur emissions can’t be negative.

    I don’t claim any expertise in this area. I just have the uneasy feeling that there is one story when all of the brightening is in prospect, and a different story when a substantial slice of the prospective brightening has already occurred. In response to Gavin’s statement that “It may also be restricted to European and US stations”, I should mention that the paper I cited said that “The main reasons for this difference [between a projected fall of 3% and an estimated actual fall of 20% in sulphur emissions] are a faster decline in the REF region (than assumed in SRES) and a slower increase in ASIA.”

  25. September 21st, 2006 at 17:24 | #25

    Ian – “The Summary for Policymakers of the IPCC TAR states that: “Temperature increases are projected to be greater than those in the SAR, which were about 1.0 to 3.5°C based on the six IS92 scenarios.”

    Seing as this is from the TAR in 2001 let see what the 4th assesment says with 5 years more data and research before getting too tied up what the TAR scenerios say.

  26. econwit
    September 21st, 2006 at 17:44 | #26

    Econoclast (brilliant name by the way)

    I can relate to it because I’m actually one.

    “and including avoiding anihilation.�
    Are you proposing that mankind has the option to gain immortality if it adopts the precautionary principle?

  27. Ian Castles
    September 21st, 2006 at 18:38 | #27

    Ender – It’s not a matter of being “tied up” at all. The sentence that I quoted from the TAR said that “The higher projected temperatures and the wider range [than in the SAR] are due PRIMARILY to the lower projected sulphur dioxide emissions in the SRES scenarios relative to the IS92 scenarios.â€? This statement was quoted by Dr. Penny Whetton, now Leader of the Climate Impact and Risk Stream in CSIRO Marine and Atmospheric Research, in her presentation to a Workshop convened by the Academy of Technological Sciences and Engineering in April 2002.

    I participated in that Workshop and subsequently wrote to the Co-Chairs (Dr. John Zillman and Mr. Jerry Ellis) questioning a number of aspects of the IPCC projections, including this one. As you know, I also questioned the demographic and economic assumptions underlying the scenarios.

    I sent copies of my letter to participants in the Workshop, including Dr. Graeme Pearman, then Chief of CSIRO Atmospheric Science. Graeme subsequently wrote to me as follows:

    “My colleagues and I believe that the issues that you have raised concerning the IPCC SRES scenarios are extremely important. Although CSIRO is increasing its efforts in socio-economic integration of its biophysical science, the reality is that in the short-to-medium term most work in this area will have to come from outside CSIRO. Clearly the [Academy of Social Sciences] could play a leading role in this process. Until your letter earlier this year, we had not really appreciated how little Australian involvement there had been in the preparation and review of the SRES scenarios� (Email message of 23 September 2002).

    Penny Whetton was reported on ABC News as recently as 2 September saying that not much has changed since the TAR. Here’s an extract from the report which is available in full at http://www.abc.net.au/news/newsitems/200609/s1731464.htm – I’ve added the CAPITALS:

    “An Australian scientist who contributes to the world’s foremost authority on climate change says the scientific consensus is that average daily temperatures WILL increase by as much as 5.8 degrees over the next century. The CSIRO’s Dr Penny Whetton says the latest assessment by the Intergovernmental Panel on Climate Change is due to be finalised by early next year. While she will not comment on what the panel’s findings are likely to be, she says NOT MUCH HAS CHANGED SINCE 2001 when the panel made its last assessment. “The science, as it stands now, IS REALLY MUCH THE SAME in that if we factor in those range of future emission scenarios and the uncertainty we have in how fast the warming will occur for a given level of greenhouse gasses – then we’re still looking at a possibility of warmings as high as 5.8 degrees,” she said …â€?

    You tell me to wait and see what the 4th assessment says. You could say the same to Penny Whetton: she knows what it says because she’s a lead author of the “Regional Climate Projections” chapter of the contribution of Working Group I. Perhaps the 4th report will say that “not much has changed” and that it’s “really much the same.” But why? If the projections don’t change when there are large changes in the empirical evidence, why bother assembling that evidence?

  28. rog
    September 21st, 2006 at 19:21 | #28

    This precautionary principle thing has its drawbacks – proponents must also argue for not against premptive miltary action.

    Ditto business, on the OH&S baby that grew into a monster the courts have recently ruled that an employer must also “prescribe, warn, command and enforce obedience” to their commands (McLean v Tedman & Anor.)

    When is enough precaution too much?

  29. jquiggin
    September 21st, 2006 at 20:16 | #29

    On the contrary, Rog, I make the point, citing Rumsfeld’s unknown unknowns remark that, if he had taken unknown unknowns seriously, he wouldn’t have sent US troops into a place that was full of them.

  30. chrisl
    September 21st, 2006 at 20:51 | #30

    The precautionary principle as it relates to climate science means we don’t have absolute proof so “lets do something” i.e. carbon tax
    What if it is the wrong something?
    The precautionary priciple could equally apply to many other probability projections e.g. floods, earthquakes, meteor strikes.

  31. Nat B Wheatley
    September 21st, 2006 at 22:06 | #31

    All very interesting. We all want perfection. Meteorologists make a model and then check it’s ability to accept past data and produce reasonable correspondence with emerging weather facts. Queensland’s vital question is whether the Mary River Traveston Crossing Dam in 3 stages will:
    1. produce useful water for SEQ before it runs out of water (one estimate circa end 2008) – or ever short of a cyclone like Innisfail.
    2. Justify the expenditure of $billions on displacing people , roads,etc and construction in a questiionable base area when alternatives with predictable outcomes like desalination are becoming cheaper with each tech advance.

    A useful base may be indicated by the Australian Rainfall trends 1950-2003 available see Google website Microsoft PowerPoint -ann_farrell.ppt.- this seems to indicate that the Hinze dam is the best bet (perhaps that is why it is the main one with much water) and implies that desalination is the only water source we can give a castiron guarantee for.

  32. Chris O’Neill
    September 22nd, 2006 at 00:46 | #32

    “Observed increase in global temperature 0.5 degrees in C20, mostly after 1970″

    John was being very conservative. He should also have included the observation since 2000. It would have been more pertinent to say “observed increase in global temperature at least 0.7 degrees C since 1900, with 0.5 degrees since 1970.”

    “Aberrations in global temperatures of more than this magnitude over longer time frames are a common occurrence.”

    So what?

    “This temperature change could be deemed “normalâ€?.”

    Who says that 0.5 degrees C in 30 years and 0.7 degrees in 85 years is “normal”?

    “I read somewhere recently that research being conducted at Newcastle University (Aust) had discovered that the formations in limestone caves, which occur over many thousands of years, provided very accurate long term records of rainfall and air temperatures over the periods of their formation.”

    Speleothems have been used in paleoclimatology for many years now.

  33. rog
    September 22nd, 2006 at 08:11 | #33

    John, prior to the US invasion of Iraq the consensus of opinion was that there was WMD, the specifics were the “unknown”. This is the crux of the Rumsfeld argument, that the evidence is indicative but not definitive.

    Richard Butler from UNSCOM was quite adamant about what he knew, he now knows better.

  34. jquiggin
    September 22nd, 2006 at 08:53 | #34

    Rog, this is an old and tired rightwing meme which has been refuted many times. Until UNSCOM was readmitted to Iraq in December 2002, most people (including me) thought Saddam had WMDs. Once the inspectors had looked at all the obvious sites and found nothing, most people of any sense had enough doubt on the matter to support continued inspections rather than an immediate resort to war.

    Quotations from all sorts of people in 2002 and earlier prove nothing. Quotations from Bush, Rumsfeld, Cheney and others in 2003 prove (yet again) that they are shameless liars (I’ll give Powell the benefit of the doubt and accept that he could not believe that, after demanding absolutely rock-solid evidence, he would be fed a bunch of lies to announce).

  35. Ken Miles
    September 22nd, 2006 at 10:43 | #35

    (7) Or the models are wrong.

    Ian, your back of the envelope calculation isn’t that useful. If you want to compare a model with historical data vs. reality, then compare a model with historical data vs. reality. Don’t handwave around like your doing here.

    As one example of the problems which you’ve ignored is the earth’s thermal inertia. This will damp the effect of a change in the radiative forcing especially over such short time periods to which you are using.

  36. econwit
    September 22nd, 2006 at 11:28 | #36

    Chris O’Neill

    “Who says that 0.5 degrees C in 30 years and 0.7 degrees in 85 years is “normal�?�

    If you are going to deem something abnormal you should adequately define normal.

    It is very difficult to get accurate records of temperature readings more than 150 years old. So without them, to pronounce short term temperature movements as normal or not is just conjecture.

    Then to propose a new tax based on this conjecture calls into question the motives of the proponents.

  37. rog
    September 22nd, 2006 at 11:59 | #37

    Who “fed the lies”? Intelligence did; David Kay resigned in protest at lack of evidence and said that GWB was owed an explanation as to why he had been deceived by the intelligence community. At no time did he blame the executive.

    This was the same intelligence that were surprised at the revelation of Libyan and Iranian nuclear programs and the fall of the Berlin Wall.

    Intelligence gather evidence and extrapolate and hope that they are right, there is nothing new in this.

    Quotations from 2003 only prove the date.

  38. rog
    September 22nd, 2006 at 12:18 | #38

    In David Kays Senate testimony he said that they (intel) had “all got it wrong” including France, Germany.

    http://www.cnn.com/2004/US/01/28/kay.transcript/

    Post 2002 UNMOVIC also issued statements that Iraq had not fully complied with disarmament.

  39. September 22nd, 2006 at 12:33 | #39

    Ian – “It’s not a matter of being “tied upâ€? at all.”

    I don’t know about this mate. By most reasonable standards you are pretty obsessed with these scenerios. And again these are scenerios that may be wildly inaccurate like most economic projections. ABARE has projected $25 per barrel oil for the last 4 years. Its climate change and technology modelling had some pretty dodgy numbers in it as did its analysis of nuclear power.

    “You tell me to wait and see what the 4th assessment says. You could say the same to Penny Whetton: she knows what it says because she’s a lead author of the “Regional Climate Projectionsâ€? chapter of the contribution of Working Group I”

    I am not sure about what Penny Whetton says, the thing to do is to wait and see what the 4th assessment actually says. Speculating from what one person says is a pretty thin argument.

    Whatever the projections we do not know what the final number for warming will be. We do not know accurately the contribution negative forcings will have. We have an estimate based on historical and present data (Anan et al) that climate sensitivity could be about 2.9° (with 90% confidence) however it could be as high as 4.5°. We don’t know what positive feedbacks are starting like permafrost melting releasing methane or albedo reductions due to less ice cover or their effect on the climate and the amount of warming.

    All this uncertainty makes your demands for precision pretty unworkable. There is no precision. Even if you personally did all the economic modelling you could still be 100% out even with the best available data. This is why the precautionary principle needs to be applied. The only real certain facts we have are that greenhouse gases cause global warming and we are producing more and more greenhouse gases. The amount of warming and/or climate change are complete unknowns. In the face of this it is normal to be cautious however we are not doing that. Again if you want scenerios that allow us to continue doing what we are doing with no changes to GDP then construct them yourself – don’t wait for the 4th assessment. The numbers can be massaged to present anything you want which is, I realise, a valid criticism of the whole IPCC scenerio modelling. However it is an equal critisism of what economic modelling anyone does. Very little modelling of this nature is done in a vacuum and is usually done with a conclusion in mind even if that is not the stated aim of the modelling.

    The main point is that we are confronted by a man made phenomenon called global warming. It is real and is confirmed by real physical data and by most people that spend their lives interpreting this data and who are qualified to interpret this data. They however, can not ever give an accurate number about the resultant climate change if any, from this warming. Therefore any economic modelling based on models of climate change are very likely to be inaccurate no matter who does the modelling. The most sensible action humanity can take is to accept that there will be reductions in wealth for some and take actions that will reduce emissions of greenhouse gases to ensure that for most of humanity the planets climate will not change too much and depart from a range where humanity can adapt to the changes in climate.

    That would be the actions of a sensible society. However while wealth and wealth accumulation are the primary objectives of society and everything else is secondary to this this is unlikely to happen. It will only change when/if something happens that puts the environment above wealth in the list of priorities.

    An finally why the IPCC does economic modelling who knows. It must have sounded like a good idea at the time however when it is subject to such nit picking that ignores the fact the the guts of the IPCC reports is the science and not the economics, then perhaps the instigators of the economic reporting are having serious second thoughts.

  40. Ken Miles
    September 22nd, 2006 at 12:42 | #40

    Another problem with Ian’s analysis is that it depends on the measurements of sulphate emissions (and more importantly) atmospheric concentrations to be accurate.

    Unfortunately, sulphates tend to be the least well known. Because of their short atmospheric lifetime it is extremely difficult to get accurate measurements of global levels. Thus scientists try to calculate this based of known sources of sulphates. Needless to say this is an area fraught with uncertainties.

  41. September 22nd, 2006 at 14:07 | #41

    Further to my previous post I have realised that there is this dilemma.

    Do I, imagining that I am a concerned and well meaning scientist, given the uncertainties in the results of global warming, massage the numbers to present an End of the World as we Know It (EotWawKI) scenerio hoping that this will prompt a majority of the wealthy people of the world to re-order their priorities? Given that if left to themselves the wealthy people of the world will not accept drastic action on climate change if it affects their wealth accumulation ability UNLESS there is a clear, proven and present danger.

    Or do I just present the scientific facts and leave it to the general population to decide what to do. In this case the majority of wealthy people whose primary interest is wealth will use these uncertainities to claim that there is no clear and present danger and that no changes are necessary. ie: it is OK to go on accumulating wealth and keep on emitting greenhouse gases in the pursuit of this wealth which is exactly what is happening at present.

    There are some, Ian most notably, that argue that the first option is exactly what the IPCC has done however if this was true I can see their possible motivation. There will be no action unless the majority of the First World realises that global warming and climate change is a clear and present danger and that wealth accumulation will have to take second place for a while, while the climate is being stabilised. Without a clear and present danger, and the climate numbers do not, at present, clearly and unambiguosly show a danger as there is so much uncertainty then I fear that no effective action will take place until such time as there is a clear and present danger by which time it will possibly be too late.

    However massaging the numbers to present a EotWawKI scenerio (if this is ever done) is also wrong no matter the good motivations hence the dilemma.

    Is there anyway out of this? BTW the wealthy people of the world are us in the First World that control something like 80% of the worlds resources and wealth despite only having 20% of the population.

  42. Ian Castles
    September 22nd, 2006 at 14:57 | #42

    Ken Miles, I explained that I don’t claim any expertise in this matter, but I was hoping to get some answers from experts on what seem to me to be pertinent questions. The response that Ender obtained from Dr. Gavin Schmidt at Real Climate was useful in that connection, but it tended to reinforce rather than allay my concerns about the IPCC climate projections.

    Let me accommodate you by providing some more historical data. I cited three studies showing steep decreases in aerosol emissions between 1990 and 2000. The most thorough of these is that reported in D I Stern (2005) “Global surface emissions from 1850 to 2000″, “Chemosphere” 58: 163-175. According to Stern’s database, global sulphur emissions in 2000 were 18% below their 1970 level and 22% below their 1990 level. The reduction between 1990 and 2000 reversed nearly 40% of the increase that had occurred in the previous half-century.

    In order to appreciate the significance of this reduction it is necessary to understand that, in order to avoid confusing users, ALL of the IPCC’s scenarios share the same values for emissions in each of the years 1990 and 2000 (see explanation of the process in Box 5-1, p. 243 of the “Special Report on Emissions Scenarios”). The decrease in global sulphur emissions between these two years as estimated at that time was 3%. If the decrease was in fact 22%, the IPCC’s estimate of the additional “total radiative forcing from GHG plus direct and indirect aerosol effectsâ€? between 1990 and 2000 would have been far greater than that shown for this period in Table II.3.11. Just how much greater is a simple question of fact, to which I would very much appreciate an answer from someone familiar with the technicalities of the IPCC simple model.

    I’d also be glad of advice of the implications of the higher forcing for projections of temperature increases, having regard to all factors including thermal inertia. In this regard I note that (a) according to Stern’s estimates, sulphate emissions declined by 20% between 1991 and 1996, so ten years have already passed since the greater part of the reduction occurred; and (b) the IPCC’s simple model projections show a temperature increase of 0.24°C between 2000 and 2010 for the A1T scenario, compared with 0.16°C for A1FI and 0.14°C for A1B – i.e. the projected reduction in sulphur emissions in A1T seems, prima facie, to be quickly reflected in higher projected temperatures in that scenario.

    In the light of Gavin Schmidt’s observation that the post-1990 “brightening� may be limited to European and US stations, it is relevant to note that the IPCC’s standardised projection of sulphur emissions in the ASIA region, published in 2000, was for an increase of 43%. Stern’s estimate, published in 2005, is for an increase of 6%. Quite apart from the implication of differences on this scale for climate projections, on which I am seeking advice, do they not also raise questions about the quality of economic modelling in the IPCC’s Special Report?

    John, Ken Miles asks me not to “handwave like I’m doing here�. I don’t think that I am handwaving – I believe that I’m raising important questions which bear on the validity and integrity of the last IPCC assessment, and that the IPCC should have considered these questions before deciding that “the SRES scenarios provide a credible and sound set of projections, suitable for use in AR4.� I also believe that governments should have asked those questions in 2003, and should continue to ask them until they get answers.

    I’m certainly not going to stop asking these questions in deference to Ken Miles, but it’s your blog and I’ll defer to you if don’t want them pursued here.

    Ender, I believe that scientists and other experts have an obligation to tell it like it is. Where did you get the figures in your last paragraph from – the last IPCC Report?

  43. Ken Miles
    September 22nd, 2006 at 15:01 | #43

    Just a quick note because I’m busy at the moment.

    I didn’t mean that stop handwaving as in stop commenting, but rather that I don’t think that your analysis is particular useful given the complexity of the climate system which your ignoring.

    Sorry for the poor wording on my part.

  44. September 22nd, 2006 at 15:58 | #44

    Ian – “I believe that scientists and other experts have an obligation to tell it like it is”

    So do I however, do those same scientists and experts, in all conscience, allow the world end up excrement creek without a paddle all the while saying piously “well I told it like it is” as we bravely paddle on.

    I don’t think that question has an answer.

    “Where did you get the figures in your last paragraph from – the last IPCC Report?”

    No a couple of sources:
    http://www.ghgonline.org/kyoto.htm
    http://hdr.undp.org/reports/global/1998/en/

  45. Ian Castles
    September 22nd, 2006 at 17:46 | #45

    Thanks Ender. That Human Development Report (HDR) that you are relying on for your information about global income distribution was published in 1998. I made extensive criticisms of this material in a report that was tabled at the United Nations Statistical Commission at its 2000 meeting. At the request of the meeting, a group of eminent statisticians examined the HDRs and found that they contained “material errorsâ€? – i.e., errors “which leave the reader with a fundamentally distorted picture of the phenomenon being described.â€?

    You can read about this in the Australian Treasury’s article “Global poverty and inequality in the 20th century: turning the corner?â€? – the details are given in Box 3 on p. 17 of the article, which is at http://www.treasury.gov.au/documents/110/PDF/Round2.pdf . See also the Treasury’s “manifestoâ€? on p. 47, which states that “International comparisons of national shares of global production and of living standards should use Purchasing Power Parities [PPPs], not exchange rates, as already agreed by national statisticians and embodied in the UN’s 1993 System of National Accounts.â€?

    I’m glad to say that the HDR Office of the UNDP accepted the criticisms and has improved its statistical presentation and reporting in subsequent issues of the HDR (see Ian Castles and David Henderson, 2005, “International Comparisons of GDP: Issues of Theory and Practice�, in “World Economics�, January-March 2005, p. 78). In fact, the UNDP recognised that the method it had followed in HDRs up to and including the 1999 Report in the 2001 HDR (see Box 1.3 on p. 20).

    Unfortunately, the UNDP’s erroneous estimates had been reproduced in a number of chapters of the contributions of Working Groups II and III to the IPCC’s Third Assessment Report, and exchange rate-converted GDP estimates and projections were also used in the IPCC Special Report on Emissions Scenarios. I advised Dr. Pachauri, the Chairman of the IPCC, of these errors in correspondence in late-2002 and also wrote to the Coordinating Lead Authors of the relevant chapters. Unlike the UNDP, however, the IPCC is apparently incapable of admitting error.

    The Australian Government Submission on the scoping of the IPCC’s Fourth Assessment Report (March 2003) urged the IPCC involve national statisticians and the UN Statistical Commission in its work, but this advice has been disregarded.

    Treasurer Costello discussed this matter in his speech to the Lowy Institute in September 2005 ( http://www.treasurer.gov.au/tsr/content/speeches/2005/013.asp ): you’ll see from the data in Table 3 of that speech that China and India alone accounted for 20% of the world’s GDP in 2004 – but these two countries account for less than 40% of the world’s population, not 80%.

    In an article reporting on the Treasurer’s speech, the leading Australian economic journalist Ross Gittins described the practice of using exchange rate conversions as “a terribly outdated and unscientific method of comparing the size of economies� and said that “No self-respecting economist uses that method� (see http://www.theage.com.au/news/ross-gittins/ costello-counts-china-as-worlds-no2-economy/2005/09/23/1126982225937.html ). But the IPCC resolutely refuses to let it go.

    Incidentally the Australian economist Colin Clark used PPP comparisons exclusively in his keynote address to the United Nations Scientific Conference on the Conservation and Utilization of Resources (UNSSCUR) on 17 August 1949, so the IPCC is now over 50 years behind the times. In the course of his speech Clark contested the contention of William Vogt (in his book “Road to Survival�, 1948) that “It is obvious that fifty years hence [i.e. In 1998] the world cannot support three billion people at any but coolie standards for most of them.�

  46. September 22nd, 2006 at 21:10 | #46

    Ian – “That Human Development Report (HDR) that you are relying on for your information about global income distribution was published in 1998. I made extensive criticisms of this material in a report that was tabled at the United Nations Statistical Commission at its 2000 meeting.”

    Now how did I know that was coming? Just wondering if you have had time to criticise the 2005 report here?

    http://hdr.undp.org/reports/global/2005/

    It reports that not a lot has changed. However that is not the point – the point is that we Australia, Europe the USA etc are vastly more wealthy than than third world countries. I am classing myself with the wealthy as are you.

  47. Chris O’Neill
    September 22nd, 2006 at 22:37 | #47

    “If you are going to deem something abnormal”

    Where did I deem something abnormal? I wasn’t the one who asserted:

    “This temperature change could be deemed “normalâ€?.

  48. Ian Castles
    September 22nd, 2006 at 22:44 | #48

    You’re right Ender. Australia, Europe & the US are vastly more wealthy than Third World countries. So?

    And on another thread you say that “dissent should be within the peer reviewed scientific community.” So does your tolerance for dissent extend to the paper in the March 2006 issue of “Climatic Change” by Alison Stegman of the Climate Risk Concentration of Research Excellence at Macquarie University, on the subject “How Should Emissions Projections Be Evaluated?”

    Alison says that there is a need for “a large scale review [of the IPCC emissions scenarios] on the grounds of statistical inaccuracies, methodological assumptions and empirical inconsistencies.” She concludes that “The IPCC has not demonstrated that the SRES emissions projections have a sound economic foundation”, and that “Because these emissions projections are used as inputs in models of temperature and climate impacts, these in turn do not have a sound economic basis.”

    And even if the economic inputs to models of temperature and climate impacts had been right (which we now know they weren’t), the model outputs don’t square with the observed trends in temperature. The reduction in sulphur emissions that the A1T scenario projects for 2030 had already occurred by 1996 but, as you acknowledge, “the rise in global temperature has been fairly steady for the past few decades”. Why? How large does the discrepancy between modelled and actual outcomes have to be, before you’d concede that there must be something wrong with the climate models? And even if the climate models are right, why persist with emissions projections which do not have a sound economic basis?

  49. econwit
    September 22nd, 2006 at 23:02 | #49

    Chris O’Neill said:

    “Who says that 0.5 degrees C in 30 years and 0.7 degrees in 85 years is “normalâ€??”"

    So it is agreed that we can not define this temperature variation as a normal or abnormal occurrence, due to there being inconclusive data to formulate such opinions.

  50. Chris O’Neill
    September 23rd, 2006 at 00:05 | #50

    ““Who says that 0.5 degrees C in 30 years and 0.7 degrees in 85 years is “normalâ€??â€?”

    So it is agreed that we can not define this temperature variation as a normal or abnormal occurrence”

    I’m not saying that either, just asking who (with any justification) says “This temperature change could be deemed “normalâ€?.”

  51. econwit
    September 23rd, 2006 at 10:18 | #51

    It was my original statement so I will elaborate on the reasoning behind it.

    Our environment by nature is revolutionary so any change could be deemed “normal�

    The GW debate is dominated with qualitative arguments as opposed to quantitive ones. Until that balance changes it is difficult to give “justification� to any arguments therein.

  52. jquiggin
    September 23rd, 2006 at 10:41 | #52

    We debated the PPP issue at length a while back. I agree that the use of PPP measures, where they are available, would be preferable, but the likely impact would be small, and the result could be either to increase or decrease projected future emissions.

    On the sulphur emissions question, I agree with Ken Miles. It’s not useful to debate this on the basis of back-of-the-envelope estimates over a short period. If you think the response should be instantaneous rather than lagged, point to the way in which the models differ from the science on this.

    More generally, Ian, I think you need to decide whether you’re acting as an advocate on the skeptical/denialist side of the debate, or as someone seeking to improve the modelling process. The two roles aren’t compatible.

  53. September 23rd, 2006 at 11:02 | #53

    Ian Castles – “You’re right Ender. Australia, Europe & the US are vastly more wealthy than Third World countries. So?”

    So my original point was that people in wealthy countries will not take action while wealth accumulation is the main priority.

    “So does your tolerance for dissent extend to the paper in the March 2006 issue of “Climatic Changeâ€? by Alison Stegman of the Climate Risk Concentration of Research Excellence at Macquarie University, on the subject “How Should Emissions Projections Be Evaluated?â€?”

    Sure that is great – why do you think I have a problem with this? Again and again you concentrate on the economic modelling and miss the science. The point of this whole post is the precautionary principle which is something you have seem to have forgotton.

    If we were sensible and applied this precautionary principle then who cares a &*&(&*& what the economic models say. As any economic modelling could be just as bad as any other and/or contain bias so they are of little or no value. You seem to want the i’s dotted and the t’s crossed before you will agree to any action on climate change that might affect the holy grail of GDP.

    You are not going to get it. There are 2 facts that I stated in my last post. That is what we know for certain. Anything else, including economics, is just speculation and could be wildely wrong or spectacularly accurate – we don’t know.

    In the face of this uncertainty the whole point of this post SHOULD be applied. We SHOULD be being cautious. However because we cannot stop accumulating wealth and that is our main priority we dismiss what scientists are telling us as speculation and faulty modelling and press on regardless madly accumulating more and more wealth.

    It would be nice if we could act before some catastophe happens that forces us to re-order our priorities. Mind you that catastrophe may never happen and we may just adapt without problems however that is a bit like thinking that a burning building will burn slow enough so I do not have to leave and stop working.

  54. Ian Castles
    September 23rd, 2006 at 22:28 | #54

    John, This is a point-by-point fisking of your comments above (“Fisk: verb – To deconstruct an article on a point by point basis in a highly critical manner. Derived from the name of journalist Robert Fisk, a frequent target of such critical articles in the blogosphereâ€?). I apologise for its length, but it’s 500 words shorter than the fisking by Roger Jones of an article by Alan Wood inThe Australian that you published some weeks ago.

    JQ: “We debated the PPP issue at length a while back. I agree that the use of PPP measures, where they are available, would be preferable, but the likely impact would be small, and the result could be either to increase or decrease projected future emissions.”

    IC: I think your memory may be failing you. Let me remind you of a few details that you did know about when we had that debate, and add a few more that you don’t.

    In your posting “Diewert on Quiggin, Castles and Henderson� on 31 March, you said:

    “These debates [about purchasing power parity (PPP) vs exchange rate (MER) converters] are inevitably complicated, but someone with the right skills can make them a lot clearer. I can think of no one better than Erwin Diewert, who has been the leading researcher in the theory of index numbers for the last thirty years… So I asked Erwin for comments and was both surprised and pleased to receive not just comments but a whole paper, not quite by return mail, but after only a few days. I think it’s fair to summarise by saying that Diewert agrees with my main point, but also agrees with Castles and Henderson that the IPCC should change its modelling approach.â€?

    Professor Diewert’s paper, dated 28 March 2006, was entitled “Comment on ‘The Choice of Exchange Rate on Modelling the Impact of Climate Change: A Response to the Castles-Henderson critique of the IPCC’ by John Quiggin.â€? Your paper – the subject of his comment – was dated 2 August 2005. I thought that it was rather odd that you sent it as a submission to the UK Stern review and, later, published it on your website, without at any time consulting David Henderson or me.

    Be that as it may, you gave your readers a mistaken impression when you said that “Diewert agrees with my main point.� In fact, Erwin’s conclusion was that you, John Quiggin, were “right to implicitly criticise the entire SRES modeling strategy�. So your statement that he “also agrees with Castles and Henderson that the IPCC should change its modelling approach� needs amendment. What you should have said was that Professor Diewert agreed with all of us that the IPCC should change its modelling approach. And he didn’t say that “the likely impact would be small.�

    After reading your interpretation of his comment, I wrote to Erwin to seek his clarification. His immediate response included the following:

    “… [W]hether the assumption of gradual convergence in per capita energy use is any more sensible than the assumption of gradual per capita real income convergence is a different matter. I am extremely sceptical on the prospects of either type of convergence occurring.â€?

    In the light of this reply, I wrote again to Erwin making four suggestions – first, that he make clear that he was not necessarily endorsing the convergence hypothesis as a prediction of the future, but was discussing the way that emissions should be modelled ON THE ASSUMPTION THAT CONVERGE WOULD OCCUR; secondly, in support of my own position that the convergence assumption as applied to per capita energy use was questionable, I suggested that he refer to the paper “Convergence and Per Capita Emissions� by two Australian economists, Alison Stegman and Warwick McKibbin (published as Brookings Discussion Papers in International Economics No. 167, May 2005); thirdly, I asked Professor Diewert if he would cite the three key papers in which the Castles and Henderson critique of the economic and statistical work of the IPCC had been fully articulated – you did not mention any of these in the posting on your website, but only an earlier piece (see below); and fourthly, I suggested that he submit his comment on your paper to the Stern review.

    On 8 April, Professor Diewert wrote to you, and copied to me, a letter in which he said “Ian Castles sent me several very useful comments on my note and so I have revised it a bit in the light of his comments. I would appreciate it if you could replace the previous version of my comment on your website with the attached version.� In the new version, Erwin cited the all three Castles & Henderson papers as I’d suggested, and added the following footnote:

    “The convergence hypothesis is somewhat questionable to say the least; see the discussion on this point by Stegman and McKibbin (2005). However, discussing the merits of various convergence hypotheses is not the purpose of this note.�

    The new version of Erwin Diewert’s paper, dated 8 April 2006, is posted on his website. It was published on the Stern Review website soon afterwards. But as of today, 23 September, you have not replaced the earlier version on your website with the later version, as Professor Diewert requested. Are you intending to do so?

    A few related questions:

    (1) On “The End of the Global Warming Debate� thread on your website (5 January, 2.49 p.m.) you said “I think the Castles critique is a complete beatup. Up to a first approximation, it makes no difference, for an exercise like this, whether you use PPP or exchange rate conversions.� Do you still adhere to this view? The following subsequent developments are relevant:

    (a) Professor Diewert said in his Comment on your paper that “Castles and Henderson are right to criticize the first part of the SRES modeling strategy, which relies on market exchange rates to calculate per capita real income differences between countries. It would be much better to use ICP PPPs for this first part of the SRES modeling strategy. The differences between PPP’s and market exchange rates can be very large so their criticism is not a negligible one.�

    (b) Dr. Alison Stegman of Macquarie University and Brookings Institution stated, in her recent paper in Climatic Change, that “Given the importance of economic activity in generating emissions, the Castles and Henderson critique highlighted a serious shortcoming in the SRES�; and that “The SRES must be based on accepted modelling and statistical practice. It is not clear what the impact on emissions of using exchange rate converted data is in the SRES because the report is not transparent in its assumptions and methodology.� If the impact of using exchange rate converted data in the SRES is not clear to Dr. Stegman, or to Professor Warwick McKibbin and Dr. David Pearce who have also studied the issue closely over an extended period and produced several papers on the subject in co-authorship with her, I wonder why it is so clear to you.

    (2) In your posting on the “Castles and Henderson, again� thread on 30 January 2006 at 9.17 am you said that you would “now respond� to the main questions that you could derive from Willis Eschenbach’s comment made on 29 January at 6.33 pm. As yet you do not appear to have responded. Are you still intending to reply to Willis’s pertinent questions, and to the questions in my related posting on 30 January at 9.05 am?

    (3) You said in the same posting that the submission that you had made to the Stern Review “was prepared fairly quickly, and is still in draft form.� Did you advise the Stern Committee that the paper was in draft form? There is nothing on the Review’s website to indicate this. Do you intend to submit a final form of your paper to the Review?

    (4) You also said in your post on the “Castles and Henderson, again� thread that you would “be happy to add [to your submission] the references Ian suggests many of which (including the House of Lords report) I have read.� Are you still intending to add the references I suggested (including to the other Castles and Henderson papers) to your submission?

    (5) You said in your initial posting on the “Castles and Henderson, again� thread that the Castles and Henderson critique had “emerged in a rather confused form, with a number of letters and opinion pieces before finally being published in contrarian social science journal Energy and Environment.� You did not mention the fact that David Henderson and I had subsequenty restated and extended our critique in the three papers that are listed in the “References� to Professor Diewert’s comment. Do you think that these papers are equally confused?

    Also relevant is the fact that my initial letters to Dr. Pachauri, Chairman of the IPCC, were sent at his invitation and that the presentations by Professor Henderson and me to the IPCC Expert Meeting in Amsterdam on 10 January 2003 were made at the Panel’s invitation. The circumstances that led us to send out these and other documents “as is� were fully explained in our “Authors’ Preface� to the first of our papers in Energy and Environment, as follows:

    “The contents of these documents are more diverse, and less systematically put together, than would have been the case if we had set out with the intention to provide a full critique. All the eight texts were prepared at short notice, in response to immediate opportunities and concerns. Critics of our critique have rightly made the point that what we are saying has not been subject to peer review. But given that the IPCC was entering into the task of preparation of its Fourth Assessment Report (AR4), and was due to meet in the third week of February [2003], we decided to send out the documents via the Internet without recasting them – as a contribution, timely albeit rough and ready, to an important debate which was already under way. We welcomed the Editor’s subsequent (and unsolicited) proposal to publish them in this issue of Energy and Environment, making only the condition, which was readily accepted, that the IPCC should be invited to contribute an article by way of comment and response. We are glad that an article by SRES authors is to appear alongside our own contribution� (“The IPCC Emission Scenarios: An Economic-Statistical Critique�, E&E, vol. 14, 2 & 3: 161).

    With respect to your description of Energy & Environment as a “contrarian journal�, I need to mention that the Report of the meeting of the IPCC Bureau in Paris on 18 February 2003 states that “The Chair [Dr. Pachauri] noted that Dr, Nakicenovic [Coordinating Lead Author of the Special Report on Emissions Scenarios] will shortly publish, in a leading international journal, an article that responds to the substance of [the Castles and Henderson] criticisms.� This “leading international journal� was Energy & Environment, which subsequently published two responses by teams of SRES authors to the Castles and Henderson critiques.

    Also relevant to your characterisation of Energy & Environment is the fact that this journal recently published an Australian volume which included the paper “Observed climate change in Australia over the past century�, by Neville Nicholls and Dean Collins of the Meteorology Bureau. Two CSIRO scientists were invited to contribute to the volume on aspects of their work on climate change issues: one declined to do so, while the other initially accepted but did not reply to subsequent correspondence from the Editor of the Australian volume. The abstract of the Nicholls and Collins paper reads as follows:

    “Temperatures across nearly all of Australia increased through the 20th century, as did sea surface temperatures in the surrounding oceans. It seems likely that much of the warming is due to increased atmospheric concentrations of greenhouse gases. Rainfall trends have been less spatially consistent than the temperature trends with areas of increase (especially in the northwest) and areas of decrease (especially in the southwest). There is some evidence suggesting that some of the rainfall trends are the result of human influences, but this evidence is less convincing than is the case with the increases in temperature� (E&E, vol. 17, no. 1, January 2006).

    Do you regard these opinions as “contrarian�?

    JQ: “On the sulphur emissions question, I agree with Ken Miles. It’s not useful to debate this on the basis of back-of-the-envelope estimates over a short period. If you think the response should be instantaneous rather than lagged, point to the way in which the models differ from the science on this.”

    IC: I believe that both you and Ken Miles have completely missed my point. The IPCC published 40 emissions scenarios in an Appendix to the SRES entitled “Statistical Tables�. There are 200 pages in this Appendix, and it says “Statistical Table� at the top of every page. It’s surprising that the IPCC did not include any official statisticians in its 53-member writing team or in the team of 89 expert reviewers (It’s especially surprising in the light of the fact that 13 of the members of the writing team were from the Netherlands, which boasts one of the most highly regarded statistical agencies in the world).

    For all emissions of greenhouse gases and aerosols, including sulphur, the 1990 and 2000 data entered in these tables were the same for every scenario, both globally and in each region. For the global totals, published in 2000, the estimates for each of the 40 scenarios showed a decrease of 3% in sulphur emissions between 1990 and 2000. There is now substantial evidence that the actual decrease was over 20%, and that most of this decrease had already occurred by 1995 – over 10 years ago. For the ASIA region, the SRES shows an increase of 42% in sulphur emissions for every scenario. According to the most thorough estimates that have been made (I acknowledged that they were uncertain) the increase in sulphate emissions in ASIA between 1990 and 2000 was only 7%.

    John, I don’t know whether the response should be instantaneous or lagged, I don’t know whether the models differ from the science, I don’t want to do back-of-the-envelope calculations and I certainly don’t know that the models are wrong. Ken Miles’s outraged reactions to the contrary notwithstanding, all I did was to identify model error as ONE of the possible implications of the huge difference between the IPCC’s estimate in 2000 and the best estimates that can now be made.

    I sought expert comment on this matter on your blog precisely because I don’t think that it’s useful to debate it on the basis of back-of the-envelope calculations. I acknowledged that an assessment of the implications was outside my own sphere of expertise. I’m fascinated that you and Ken Miles don’t see the need to explore this for yourselves, but abuse me for trying to do so.

    It seems to me to be bizarre that on a matter of such importance I should be having to guess in 2006 about the implications of the IPCC’s lack of knowledge in 2000 of significant changes in the world’s atmosphere that occurred between 1990 and 1995. Why are you putting the onus on me to “point to the way in which the models differ from the science�? Instead of proclaiming three years ago that “the SRES scenarios provide a credible and sound set of projections, appropriate for use in the AR4�, and accusing David Henderson and me of spreading disinformation and of “questioning� the scenarios (heresy!), the IPCC milieu should have been acting promptly to correct this and other inaccurate information that they had inadvertently provided to governments and researchers, and advising on the implications. The SRES Team were quick to proclaim that “Mr. Castles and Mr. Henderson have focused (at tedious length) on constructing a ‘problem’ that does not exist�, but the leading researcher in the theory of index numbers for the past thirty years seems to think that the problem does exist.

    JQ: “More generally, Ian, I think you need to decide whether you’re acting as an advocate on the skeptical/denialist side of the debate, or as someone seeking to improve the modelling process. The two roles aren’t compatible.”

    I’ll respond to this comment when you’ve answered the questions I’ve raised above.

  55. jquiggin
    September 24th, 2006 at 06:39 | #55

    That’s a long fisking for a three-para blog comment! I’ll try to respond in due course, but for the moment I’ll just restate my main point.

    In an internally consistent economic model, the aggregation procedure used to derive national income index numbers should have only a small effect on predicted values of other variables, such as CO2 emissions.

  56. Ian Castles
    September 24th, 2006 at 08:32 | #56

    Ender, There was an interesting piece in the Sun Herald on 2 September by Ed Shann, former chief economist at Shell Australia, under the title “Some say peak oil, some say global warming.” Ed pointed out that the peak oil advocates who say oil output will be determined by supply and the global warming advocates who see booming energy supply and demand cannot both be right. I’ve had the impression from your posts that you think that both camps ARE right, but maybe you’ll correct me on that.

    Anyway, Ed was certainly correct in pointing out that “estimated carbon emissions are based not on science, but on economics, involving assumptions about world population, economic growth, energy demand, fuel mis, technology and prices.” He has much the same opinion of the value of economic models as you do.

    You say that “again and again [I] concentrate on the economic modelling and miss the science.” No I think it’s the scientists who concentrate on the economic modelling (i.e., the emissions scenarios). The present suite of models conjure up a series of scenarios of the future in which either the whole world is extremely wealthy and even the poorest countries use several times as much energy per head as the richest countries do today, or the global population rises to levels that no demographer now thinks possible. The resulting emissions scenarios are not credible.

    I’m interested in the science and I’d like scientists to explain why the predictions of rapid global warming that were being made 20 years ago haven’t been realised. Some months ago I said on a blog (I’ve forgotten which one) that Ian Lowe, now President of the Australian Conservation Foundation, had forecast in his book “Living in the Greenhouse” (1989) that by the time his youngest son, who was 35 years younger than he was, had reached the age that he was then, the world would be warmer by 3 degrees (apologies to Ian Lowe if I haven’t got the words of the quote right, but the substance of the point was that the world would warm by 3 degrees by about 2025).

    I pointed out that half of the 35-year period had now passed and that according to the observational record the world had warmed by, at most, 0.3 degrees: the rate of warming has been only about one-fifth the rate that Professor Lowe had predicted. I asked why this was the case – I suppose this is the sort of question that leads John Quiggin to allege that I’m “an advocate on the skeptical/denialist side of the debate” rather than “someone seeking to improve the modelling process.” But I sm in fact seeking to improve the modelling process.

    The answers to my question were fascinating. No one accepted that there might have been something wrong with the models of 20 years ago – no, the emissions projections that had been fed into them must have been astray.

    Well, they certainly were: no one in 1990 could have predicted that over one-third of the build-up in the concentration of sulphate aerosols in the previous half-century would be reversed within 5 years. My back-of-the-envelope calculations suggest that by now that reduction in negative forcing should be affecting temperatures, if the models are right. If a climate scientist can show how I’m wrong about that, of course I’ll accept it. But I won’t lie down just because Ken Miles says that my analysis is not particularly useful “given the complexity of the climate system which [I'm] ignoring.”

    The last IPCC assessment reported that global temperatures declined slightly between 1945 and 1975 despite a large rise in CO2 concentrations in the atmosphere. The commonly-accepted explanation for that is that the rise in temperatures that would otherwise have occurred was masked by rising aerosol burdens. Ken Miles, do you agree that explanation? Or do you think that it ignores the complexity of the climate system?

  57. chrisl
    September 24th, 2006 at 09:11 | #57

    Computer models are really probability machines. Put in a lot of assumptions with a proability attached. If you had a very good probability of each assumption (say 90%) after putting just five of these assumptions together the probability drops to around 50%. A toss of a coin!

    Imagine how many assumptions need to be made for a climate model!

  58. Ian Castles
    September 24th, 2006 at 09:51 | #58

    Thanks for your interim response John. On my reading of Erwin Diewert’s comment, he considered that your main point was an implicit criticism of the entire SRES modelling strategy. He also said that your point that “In a fully-disaggregated multi-sector general equilibrium model, aggregate index numbers play no role” was “somewhat irrelevant to the problem at hand” and was “not particularly helpful in modeling the catch up process.”

  59. September 24th, 2006 at 10:09 | #59

    Ian – ““Some say peak oil, some say global warming.â€? Ed pointed out that the peak oil advocates who say oil output will be determined by supply and the global warming advocates who see booming energy supply and demand cannot both be right.”

    The point about Peak Oil is that it is not about running out of oil. It is simply the point where supply, no matter what is done, levels off and declines and fails to meet demand. This has huge implications for global warming. As global oil supplies get tight, and it is right now – having to drill though 3 km of rock under 2 km of ocean is getting pretty desperate, we will turn to tar sands and coal to liquids to try to maintain supply. Both of these options release vastly more CO2 that present oil production and could accelerate CO2 emissions rather that reducing them.

    “….The resulting emissions scenarios are not credible.”

    You are absolutely right – so whats the problem? Perhaps it indicates that present growth is unsustainable?

    “I’m interested in the science and I’d like scientists to explain why the predictions of rapid global warming that were being made 20 years ago haven’t been realised.”

    Scientists have explained it. There is a lag due to the heat sink in the oceans. That is why the southern hemisphere is warming slower than the northern – more ocean in the south. Also science is always getting more data and an important part of science is revising and incorporating new data into theories. Again Ian Lowe may just have been wrong in saying that warming would be 3 deg back then.

    “No one accepted that there might have been something wrong with the models of 20 years ago – no, the emissions projections that had been fed into them must have been astray.”

    Again it has been explained to you at enormous length (sigh) on many occasions and many blogs that no-one has any illusions about the accuracy of climate models. Scientists do not use them to predict exaclty what the climate will be in say 20 years but rather to run experiments and learns what may happen. Climate models also get better with better data.

  60. jquiggin
    September 24th, 2006 at 10:10 | #60

    “Computer models are really probability machines. Put in a lot of assumptions with a proability attached. If you had a very good probability of each assumption (say 90%) after putting just five of these assumptions together the probability drops to around 50%. A toss of a coin!”

    Better not fly a plane any time soon, Chris. They are all designed using computer models. More seriously, your description involves a misunderstanding of the way in which models work. Good models do not rely critically on the conjunction of assumptions in the way you describe.

  61. jquiggin
    September 24th, 2006 at 10:34 | #61

    Ian C, comments like those you’ve made about Ian Lowe are indeed the kind of thing that concerns me. Why pick on a popular book by a non-climate scientist when projections made by actual climate scientists like James Hansen have been pretty much spot-on.

    And I assume you would agree that the claims that the denialist/skeptic side were making well into the 1990s (about urban heat islands, the satellite and balloon record, the idea that the observed trend was just a short-run fluctuation) have fared far worse than the projections of mainstream science, yet I rarely see you make this point.

  62. chrisl
    September 24th, 2006 at 11:01 | #62

    A better analogy to Climate models would be if planes took off totally at random,with no timetables or traffic controllers. i.e chaos. Who would care to predict the outcome then?

    Would you get in a plane if you were given a range of “scenarios” as to where and when you may land?

  63. Ian Castles
    September 24th, 2006 at 11:03 | #63

    Ender, Thanks for your agreement that I’m absolutely right that the emissions scenarios are not credible. Can I take it that you have the same view of the projected increase in temperatures?

    I think that Ian Lowe was relying on the scenario prepared for the GREENHOUSE 1987 Conference at Monash University organised by the CSIRO Division of Atmospheric Research. The statement prepared for that conference was headed “Climate Change in Australia to the Year 2030 AD”, and said that “A rise of 2 to 4 degrees C in the annual mean temperature is predicted.” It also said that “While the predicted changes in the gross features of the global climate are highly probable, the regional changes suggested in this scenario are more speculative.”

    The CSIRO now puts the projected range of global temperature increase between 1990 and 2030 at 0.54-1.24 degrees C, so the range of warming that was thought to be “highly probable” in 1987 has now been reduced by 70-75%. The upper end of the range is only as high as it is because of the increased negative forcing from the reduction in sulphur emissions that is now expected (and which has in fact already occurred). So what exactly is the new data that “science is always getting” that has led to a big REDUCTION in projected temperatures? Is it possible to get an answer from a scientist on this point?

  64. September 24th, 2006 at 11:24 | #64

    Ian – “Thanks for your agreement that I’m absolutely right that the emissions scenarios are not credible.”

    No that is not what I said at all. I said that endless growth is not sustainable and indicates that there will be a discontinuity in the future where the limits to growth are reached. That is why they are not credible. They will continue to grow until such time as they can’t. You seem unable to accept that there are limits. Again even if you had done all of them yourself they would be no more credible as accurate predictors of the future than any other modelling. They MAY indicate the range that future growth MAY fall into in the future. No more or less that this can be said about any modelling however accurate.

    “Can I take it that you have the same view of the projected increase in temperatures?”

    As far as the science is concerned the conditions that we are setting ie: pumping billions of tons of greenhouse gases which control the thermostat into a chaotic system that we understand so little then yes the rise in temperatures will continue. The real fear is that we are underestimating the rise and when positive feedbacks start to kick in as they are now the rise could get very swift far beyond the conservative predictions that scientists agree to now.

    Also as a chaotic system the atmosphere has many ‘stable’ states. It is the nature of chaotic systems to very quickly change from one state to another in response to a stimulus or ‘pumping’. We are and have been for 8000 or so years in a warm wet state of the interglacial. Pumping the atmosphere system MAY actually tip the earth into another stable state. This could happen VERY quickly, as in the Younger Dryas, over decades and leave the Earth in a very different climate regime like cold/dry. One of the times in the past the Earth was in cold/dry the human population got down to something like 20 000 individuals.

    This is why we must be cautious. We do not know enough about the climate to predict exactly what it is going to do and it may do something that we never predicted. This is why rabbiting on about economic models and this and that makes no sense. Whatever happens in the future and whatever the cost we should be cutting back drastically on greenhouse emissions to stop pumping the system.

  65. Ian Castles
    September 24th, 2006 at 11:36 | #65

    John, My reply to Ender answers your point also. The climate projections to 2030 that I’ve quoted are published in Pearman, G.L., ed., 1988, “Greenhouse: planning for climate changeâ€? (CSIRO Division of Atmospheric Research), pps. 737 ff. In Australia, I don’t see how you can get more mainstream than that.

    James Hansen’s latest projections are in his December 2005 paper (with 45 co-authors, including Gavin Schmidt of Real Climate) “Dangerous human-made interference with climate: a GISS midel E studyâ€? (Geophysical Research Letters, submitted). According to this paper the projected warming to 2100 in IPCC scenario B1 is 1.1 degrees C (p. 23). In the US, I don’t see how you can get more mainstream than that.

    The projected increase in fossil CO2 emissions in the B1 marker scenario from 2000 to 2030 is 62.3%, which is exactly the same as the growth in energy-related CO2 emissions under the Reference Scenario of the International Energy Agency, as published in “World Energy Outlook 2005�.

  66. chrisl
    September 24th, 2006 at 11:49 | #66

    Ian-
    – What you seem to be saying is that we can predict the eath’s temperature by predicting the amount of co2. We can predict the amount of co2 by the world’s economic growth. And we can predict the world’s economic growth by… you will have to help me out here…

  67. Ian Castles
    September 24th, 2006 at 11:57 | #67

    Chrisl, I’ve been so busy disagreeing with John and Ender that I haven’t had a chance to say that I agree with you.

    The draft IPCC Fourth Assessment Report says “Projected probability ranges (mean plus or minus 1 standard deviation) for globally-averaged surface warming in 2100 compared to 1980-2000 … are scenario dependent and estimated to be … 3.0-5.0 degrees C for the … A2 … scenario.â€?

    What it doesn’t say, and what I bet the IPCC won’t say, is that the A2 scenario projects a global population of 15 billion in 2100 and that the International Institute of Applied Systems Analysis (IIASA). which prepared the population projection used in that scenario, puts the subjective 95% probability range for population in 2100 at 4.3-14.3 billion. Or at least it did put the 95% probability limits for global population in that range in 2001. The chance of global population exceeding 14.3 billion in 2100 would now be well below 2.5%, and it decreases with every year that the global demographic transition proceeds. The UK Stern Review discussion paper used the the IPCC’s A2 as its “business-as-usual” scenario.

    As with the projections of sulphur emissions, the views of the IPCC’s modellers in the late-1990s would be only an historical curiosity now, but for the fact that they were enshrined in the Special Report on Emissions Scenarios and the IPCC has made an “ex cathedra” pronouncement that these are sound and suitable for use in AR4.

  68. jquiggin
    September 24th, 2006 at 12:25 | #68

    Ian, on your final point, and much of the discussion above, I think it’s unhelpful to conflate discussion of climate-science issues like the modelling of SO2, about which none of us here know very much, with discussion of economic projections, where we can have a useful discussion. If you want information on climate-science topics, I suggest you raise these questions at Real Climate.

    I’ll try to respond to your other points before too long.

  69. chrisl
    September 24th, 2006 at 12:47 | #69

    Ian , I have often wondered what it is that is going to turn the earth’s temperature graph upwards so sharply.Given the previous century rise of .06 degrees and according to the CSIRO a rise of 3 parts per million in co2 last year,you could almost describe that as no change/nothing to see here.
    However in the next 94 years we are projected to have a temperature rise of 3-5 degrees.
    A population of 14.3 billion would certainly explain things nicely.

  70. Brian Bahnisch
    September 24th, 2006 at 15:22 | #70

    Ian Castles/Ender, I’m no scientist so it is a case of where angels fear to tread. But I found the diagram of climate forcings on p6 of Hansen’s Scientific American article helpful. There are positive and negative aerosols. Also I understand they persist in the atmosphere for a much shorter time than co2 – 15 years vs 100 years plus. Beyond that I can’t help.

  71. Brian Bahnisch
    September 24th, 2006 at 15:34 | #71

    Econoclast said:

    And the biggest indisputable fact – we are pumping ****loads of it into the atmospere! More than the earth has ever had done to it before.

    Not everyone takes James Lovelock seriously, which doesn’t mean he’s wrong. He says the best analogy is 55 million years ago, when similar quantities of carbon were released into the atmosphere. James Zachos has found that this time we are releasing it 30 times faster.

    On that occasion the temperatures went up 5C at the tropics and 8C in the more temperate regions. It took 200,000 years to return to the pre-event trend line.

    If nothing else a good argument for the precautionary principle!

  72. Ian Castles
    September 24th, 2006 at 16:39 | #72

    Brian, I’d like to respect John’s ruling that I not discuss climate science issues on this blog. However, the projections of sulphur emissions used by the IPCC ARE economic projections and, as I pointed out above, the IPCC’s simple model climate projections are specifically stated to be based on the assumption that the global burden of sulphate aerosols varies directly and immediately with emissions: see the Note to SRES Table II.2.7: “Global burden [of sulphate aerosols] is scaled to emissions: 0.52 Tg burden for 69.0 TgS/yr emissions.”

    So I don’t see how you can be right that these aerosols persist in the atmosphere for 15 years – if they did, the projections of burdens would not be scaled to current emissions but would be some sort of function of emissions over the previous 15 years

    I think the forcing chart in Hansen’s paper is essentially the same as that given in the Summary for Policymakers of the last IPCC Report at http://www.grida.no/climate/ipcc_tar/wg1/figspm-3.htm . The forcing assumptions in this diagram would be those used in the Hansen et al paper that I’ve cited, which finds a temperature increase to 2100 of 1.1 degrees C for the B1 scenario.

    Even for the A2 scenario and a global population of 15 billion the projected warming in the Hansen et al simulation only reaches 2.7 degrees C. The Hansen simulation for the A1B marker scenario (which assumes “very high” economic growth, “very high” per capita income and “very high” energy use – SRES Table 6-2a) is for a warming of somewhere between 1.1 and 2.7 degrees C.

  73. Ian Castles
    September 24th, 2006 at 16:51 | #73

    My statement that “the forcing assumptions in this diagram would be those used in the Hansen et al paper” is carelessly worded. The paper says that “We carry out climate simulations for 1880-2100 with GISS modelE driven by measured or estimated forcings for 1880-2003 and extended to 2100 for IPCC A2, A1B and B1 scenarios …” So the measured or estimated forcings underlying the GISS model would be reflected in (a) the estimates shown in a diagram of the type that appeared in Scientific American and (b) the climate projections in Hansen et al.

  74. jquiggin
    September 24th, 2006 at 16:53 | #74

    Working backwards through your comments, Ian, I don’t see it as particularly useful to debate whether Energy & Environment is a contrarian journal. The editor is generally regarded as a skeptic and the journal publishes a lot of papers in this vein. On the other hand, as you say, it publishes some papers with other views.

    More generally, I don’t want to spend a lot of time on third-order issues like this, which are irrelevant to the main point at issue. So, as regards the various points about referencing, version control and so on, my response is that I will deal with them when I get time.

  75. jquiggin
    September 24th, 2006 at 18:20 | #75

    As regards your comments above, Ian, are the temperature changes you refer to estimated for the period 2000-2100 or do they include the warming that has already taken place? Even with the latter assumption, I find it hard to see how you can refer to warming of “only” 2.7 degrees. If it’s the former, then we are talking about a temperature change of more than 3 degrees relative to the pre-intervention situation.

  76. Ian Castles
    September 24th, 2006 at 18:26 | #76

    John, Here’s what you said of a paper in Energy & Environment on 27 January last, on the thread “More nonsense on global warming�:

    “… The abstract is enough to tell me that this paper wouldn’t have got up at any reputable journal. It’s just a fancy restatement of the tired contrarian talking point that global temperatures declined in the middle part of the 20th century (aerosols, anyone?). By the way, given that E&E purports to be a social science journal, why is Boehmer-Christiansen publishing climate science papers (apart from the fact that no-one else would take them).â€?

    Now you’ve decided that (a) you think it’s unhelpful to discuss issues like the modelling of sulphate aerosols “about which none of us here knows very much�; (b) you “don’t see it as particularly useful to debate whether Energy & Environment is a contrarian journal�; and (c) you “don’t want to spend a lot of time on third-order issues.�

    I won’t bother to point the moral, but I think that it’s fair to point out that Energy & Environment could publish more papers with “other views� if the relevant experts were prepared to submit them to E&E rather than publish in house journals or in publications that are known to have friendly reviewers.

    I mentioned earlier that a CSIRO scientist had declined E&E’s invitation to contribute a paper on CSIRO’s regional climate projections to the Australian volume that was published last January. In the event, eight members of the CSIRO Climate Impacts and Risk Team (including three lead authors of the forthcoming IPCC Assessment Report) published the paper that they could have submitted to E&E as “Whetton, P. H., McInnes, K. L., Jones, R. N., Hennessy, K. J., Suppiah, R., Page, C. M., Bathols, J. M., and Durack, P. J. (December 2005). Australian climate change projections for impact assessment and policy application: a review (CSIRO Marine and Atmospheric Research Paper 001).

    I read this paper for interest and was surprised to find that these scientists believed that “the SRES scenarios currently available were deliberately constructed to be equally plausible� (p. 32). As I had pointed out that this was not the case in a widely circulated letter that I had sent to the Academy of the Technological Sciences and Engineering in April 2002, and 15 members of the SRES Team had reiterated this in their first intemperate response to Castles & Henderson in May 2003, and I had travelled to Melbourne at my own expense for discussions with the CSIRO Climate Impacts Team (including several of the authors of this paper) in September 2004, it was disappointing to find that these scientists still had it wrong in December 2005. I wrote to one of them in March 2006 pointing out the error. He agreed that the statement was wrong and said that it would be corrected, but so far the statement remains in the CSIRO paper. My guess is that the error won’t be corrected or even admitted, because to do so might prejudice CSIRO’s remunerative consultancy business in producing “climate change projections for impact assessment and policy application.�

    In my view, this reflects very poorly on CSIRO.

  77. jquiggin
    September 24th, 2006 at 20:53 | #77

    Ian, it’s pretty clear what I think of E&E. I was hoping to focus our discussion on more relevant issues than this.

  78. Ian Castles
    September 24th, 2006 at 22:47 | #78

    John, I can’t find any clear statement in Hansen et al about when the projection of 2.7 degrees C dates from – I think it’s probably from the end of the period used to model the forcings, i.e. 2003.

    In using the word “only�, I didn’t intend to imply that warming of this order would not be extremely serious. The “only� is by comparison with the inflated numbers commonly used in public discussion, including by leading spokespersons for the IPCC, as if they were predictions of the actual future temperature. For example, the top of the IPCC’s temperature range went up from 4.0 degrees C in the TAR draft of 6 November 1999 to 5.0 degrees C in the second draft of 16 April 2000, and then to 5.8 degrees C in the third and final draft of 22 October 2000. IPCC Chair Bob Watson reportedly told COP 6 at the Hague that new forecasts (sic) put the expected (sic) temperature rises until 2000 at between 1.5 and 6.0 degrees C – double the previous estimates.

    Last February I complained to the ABC about the Four Corners “The Greenhouse Mafia� documentary in which the narrator had said that “By 2050, [carbon dioxide emissions] are expected (sic) to more than double, causing a dramatic increase in warming of as much as four degrees.� In response, I was told that “Climate change scientist Dr. Graeme Pearman, who appeared in the program, says ‘the kinds of expectations (sic) from what is now a very solid set of science is that we could have several degrees change in temperature this century possibly as much as five degrees.’�

    Against the background of statements such as these, I thought it was fair enough to characterise the Hansen et al projection (not estimate) as I did, bearing in mind that it was derived from a scenario which put the end-century population well above the top of the 95% confidence range. I don’t think a simulation based on A2 which was carried out in 2005 can properly be characterised as “a temperature change of more than 3 degrees relative to the pre-intervention situation”, because A2 is based on a hypothetical outcome that might have been considered plausible ten years ago but can’t be regarded as plausible any more.

    But I’m happy to clarify that I didn’t mean to suggest that an increase of “only� 2.7 degrees from now (with a further increase after 2100) would not be a matter for extreme concern.

  79. Chris O’Neill
    September 25th, 2006 at 01:52 | #79

    “Until that balance changes it is difficult to give “justificationâ€? to any arguments therein.”

    That’s fine. I now know that econwit makes arguments that he knows he cannot justify.

  80. jquiggin
    September 25th, 2006 at 05:55 | #80

    Ian, you appear to be confusing point estimates with upper bounds of ranges, and disagreements with scenarios with disagreements about reporting.

    A point estimate of 2.7 is certainly consistent with a range going up to 4 degrees, so, given the choice of scenario, there is nothing wrong with the statements you’ve cited. On any sensible analysis of costs, low-probability events at the upper end of the range are going to play a large role.

    I agree that a population estimate of 15 billion is implausible, even as an upper bound, though it seemed possible not long ago. However, it would be more helpful to make specific criticisms like this in the context of a constructive contribution to the modelling process, rather than mingled with a general attack on the IPCC and all its works, raising a whole range of unrelated issues.

  81. econwit
    September 25th, 2006 at 11:55 | #81

    Chris O’Neill

    “I now know that econwit makes arguments that he knows he cannot justify.�

    That comment has been put to me so many times before I’m beginning to think there could be some basis to it, but I’m as yet to see* any convincing justification or evidence. Your line of argument is in a very similar mode to the GW debate, lots of conjecture (hot air) very few facts.

    * ps. I could be blind?

  82. econwit
    September 25th, 2006 at 11:58 | #82

    Chris O’Neill

    “I now know that econwit makes arguments that he knows he cannot justify.�

    That comment has been put to me so many times before I’m beginning to think there could be some basis to it, but I’m as yet to see* any convincing justification or evidence. Your line of argument is in a very similar mode to to proponents of the GW debate, lots of conjecture (hot air) very few facts.

    * ps. I could be blind?

  83. chrisl
    September 25th, 2006 at 15:53 | #83

    Ian, Why do you think the IPCC has bothered to predict/construct a scenario of Global temperature in 2100 given the difficulties and uncertainties involved?
    You have already shown that sulphur emmissions and world population predictions were wildly inaccurate to name only two of the numerous assumptions that have been made.
    Wouldn’t it have made more sense to construct a scenario for five year intervals given the uncertainties?

  84. September 25th, 2006 at 18:40 | #84

    Ian – the main problem with your arguments seems to be this. You seem to be pretty fixed to the idea that X economic activity = Y greenhouse emissions. ie that economic activity causes greenhouse emissions therefore more economic activity = more greenhouse. You are also arguing that the IPCC got the economic projections wrong, in your view, therefore the economic activity in say 2100 will be less then what the IPCC projected and that the trend is that economic activity/greenhouse emission ratio is dropping therefore even the higher activity will lead to less emissions.

    Have I got that right?

    If so then you are not taking into account that the actions of the atmosphere is not coupled only with economic activity. As has been pointed out before we have not seen all the rises due to positive feedbacks like the melting permafrost and the lowering of albedo due melting ice. Not to mention the fact that warmer oceans absorb less CO2.

    In the future the neat relationship you see between economic activity and emissions may fail and emissions may increase far beyond what would be predicted by you from economic activity alone. This would also drive warming into the upper regions of the conservative ranges that the IPPC will publish.

  85. Ian Castles
    September 25th, 2006 at 20:07 | #85

    Ender, The short answer to your question “Have I got that right?” is “No”. This is a complex issue, but could I suggest that, as a first step, you read Ed Shann’s piece in the Melbourne “Sun Herald” of 2 September, to which I referred you in my posting of September 24 at 8.32 am?

  86. September 25th, 2006 at 20:46 | #86

    Ian – “estimated carbon emissions are based not on science, but on economics, involving assumptions about world population, economic growth, energy demand, fuel mis, technology and prices”

    This is what you said that Ed Shann said. Isn’t this pretty much how I summerised it?

    BTW I cannot find the article – if you have a copy I would read it.

  87. Ian Castles
    September 25th, 2006 at 22:35 | #87

    Ender, The following extract is pasted from section 9.3.3 of IPCC “Climate Change 2001: The Scientific Basis.” The added CAPITALS are mine. You have yourself referred to temperature rises DUE TO POSITIVE FEEDBACKS. I acknowledge that the strength of the feedbacks is uncertain, but it is my understanding that the temperature projections depend ultimately upon the radiative forcing from the SRES emissions scenarios, and that these rest in turn upon assumptions about world population, economic growth, energy demand, fuel mix, tchnology and prices. These assumptions cannot be reduced to the simplistic foumulation “more economic activity = more greenhouse”:

    “The calculation of radiative forcing from the SRES emission scenarios for the temperature projections presented here follows closely that described in Chapters 3, 4, 5 and 6, with some exceptions as described below. Further details of the forcing for the collective procedures (MAGICC model) are given by Wigley (2000). Atmospheric concentrations of the greenhouse gases ARE CALCULATED FROM THE EMISSIONS using gas cycle models… To be consistent with Chapter 3, CLIMATE FEEDBACKS ARE INCLUDED and the model has been tuned to give results that are similar to those of the Bern-CC and ISAM models for a climate sensitivity of 2.5°C (Chapter 3, Figure 3.12). The strength of the climate feedbacks on the carbon cycle are very uncertain, but models show they are in the direction of greater temperature change giving greater atmospheric CO2 concentration.â€?

  88. September 26th, 2006 at 08:27 | #88

    Ender – “These assumptions cannot be reduced to the simplistic foumulation “more economic activity = more greenhouseâ€?:”

    So what is a summary of your position in 100 words or less?

  89. Ian Castles
    September 26th, 2006 at 09:41 | #89

    Ender, Under the IPCC’s B1T MESSAGE scenario, economic activity, as measured by GDP at market exchange rates, is projected to increase between 2000 and 2100 by a factor of 12. Economic activity as measured by GDP at what the IPCC wrongly describes as purchasing power parity is projected to increase over the same period by a factor of 10. After taking account of the IPCC’s assumptions relating to energy demand, fuel mix, technology and prices, fossil fuel carbon dioxide emissions under this scenario are projected to DECREASE by more than 50% between 2000 and 2100. That is 99 words.

  90. September 26th, 2006 at 10:25 | #90

    Ian – “fossil fuel carbon dioxide emissions under this scenario are projected to DECREASE by more than 50% between 2000 and 2100″

    Just a clarification is this total fossil fuel CO2 emissions or emissions per unit of GDP and/or economic activity?

  91. Ian Castles
    September 26th, 2006 at 10:49 | #91

    Ender, It is total fossil fuel CO2 emissions. The actual levels are 6.90 GtC (= 25.3 Gt of CO2) in 2000 and 3.33 GtC (= 12.2 Gt of CO2) in 2100. If CO2 emissions from land-use changes are included, the totals become 7.97 GtC (=29.2 Gt of CO2) in 2000 and 2.68 GtC (=9.8 Gt of CO2) in 2100.

  92. September 26th, 2006 at 14:14 | #92

    Ian – “Ender, It is total fossil fuel CO2 emissions. The actual levels are 6.90 GtC (= 25.3 Gt of CO2) in 2000 and 3.33 GtC (= 12.2 Gt of CO2) in 2100. If CO2 emissions from land-use changes are included, the totals become 7.97 GtC (=29.2 Gt of CO2) in 2000 and 2.68 GtC (=9.8 Gt of CO2) in 2100.”

    so therefore you think that the warming will be less that what the IPCC reports? Or do you think it will still be dangerous?

    Also if your projections are true then a halving of total CO2 emissions by 2100 approx a decrease per year of 0.9%. Now if this is true we should be seeing this now as it should be part of the trend. Unless of course CO2 emissions rise, reach a maximum then fall away. As they are now increasing and show no signs of decreasing what do you attribute the falling CO2 emissions to?

  93. Ian Castles
    September 26th, 2006 at 15:18 | #93

    Ender, These are not my projections: they are the IPCC’s. I said that your formulation “more economic activity = more greenhouse” was simplistic and you asked me to summarise my position in less than 100 words. I pointed to one of the IPCC’s scenarios – there are several more – in which economic activity is projected to go massively up and greenhouse emissions are projected to go substantially down. I’d say that, irrespective of what actually happens, the projection itself shows that more economic activity does not necessarily mean more greenhouse.

    Under the scenario in question, fossil fuel CO2 emissions DO “rise, reach a maximum and fall away”. Specifically, they rise by 42% between 2000 and 2030 and then decline by 66% between 2030 and 2100.

    If you believe that, because emissions are increasing now, they can’t begin to decrease in 25 years’ time, your argument is with the IPCC.

    Note that this scenario does not explicitly address any climate change initiatives such as the Kyoto protocol (SRES, p. 23) and does not include any technologies that had not been demonstrated to function on a prototype scale at the time that the Special Report was prepared (SRES, p. 216).

  94. September 26th, 2006 at 16:19 | #94

    Ian – “These are not my projections: they are the IPCC’s.”

    So what are your projections?

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