Presentation: climate change and the precautionary principle

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

94 thoughts on “Presentation: climate change and the precautionary principle

  1. 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.

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

  3. 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.

  4. “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.

  5. 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.

  6. 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?

  7. 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?

  8. 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?

  9. 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.

  10. 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?

  11. 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.

  12. 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€?

  13. 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?

  14. 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.

  15. 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?

  16. 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.

  17. 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?

  18. 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).

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