Motes and beams

The Oz and Andrew Bolt have a tag team attack on me today (Google it if you want). Most of it consists of quotations, with lots of ellipses, that are meant to show me as a dangerous radical. I can’t say I’m too upset by that – from their perspective, it’s a fair assessment. But Bolt also repeats his claim that I made a factor-of-5 error in my estimate of the impact of Australia’s current 2020 target on global temperatures.

This is a striking piece of chutzpah, given that this estimate was made in the process of correcting a calculation by Bolt, which was out by two orders of magnitude. But it has finally provoked me to clear up some of the confusion on this. The starting point was this post by Bolt who used a calculation by Damon Matthews that each tonne of CO2 emitted into the atmosphere changes the equilibrium temperature by 0.000 000 000 0015 degrees, that is 1.5*10^-12 in scientific notation. Noting that the carbon price is expected to reduce emissions by 160 million tonnes per year by 2020, Bolt made the calculation that the emissions avoided in the year 2020 will reduce equilibrium temperature by 2.4*10^-4 or 0.00024 degrees, and treats this as an estimate of the impact of the policy.

This is an amazing howler on Bolt’s part. He’s only counted one year of emissions reductions for a policy that is supposed to permanently reduce emissions. I made the very quick calculation that, if the policy stays in place until 2100 and that the 2020 reduction in emissions was maintained over this period, the number used by Bolt would imply a reduction of 0.02 degrees. I did another rough calculation that came out the same way.

Bolt came back with a lower estimate by Roger Jones, who suggest that the policy would reduce temperature by only 0.004 degrees, lower by a factor of 5 than my estimate, but higher by a factor of 20 than Bolt’s silly calculation.

At this point I slipped up. As a result of a misunderstood conversation with Roger, I gave an incorrect explanation for the discrepancy. Roger subsequently advised that he had made his calculation using a standard modelling tool called MAGICC. I finally got around to downloading MAGICC, and trying it out, so I can now give an explanation for why our estimates differ. There are three main points

(1) The most important factor is that we are estimating two different things. MAGICC produces estimates of the temperature change by 2100, but the atmosphere takes a long time to reach equilibrium. For reductions in CO2 emissions spread out over the rest of this century, the change by 2100 is only about half the long run equilibrium change.

(2) Estimates of the sensitivity of the global climate to changes in CO2 concentrations vary. The most common measure is the equilibrium temperature change for a doubling in atmospheric CO2. Until recently MAGICC used 2.6 degrees as the default, on the low side of most estimates. I used 3.5, which gives a value around 30 per cent higher

(3) Finally, while it’s obviously silly to assume, like Bolt, that the policy is in effect for only one year, it’s not entirely clear how we should project its impact into the future. That depends on baseline projections of emissions from which to calculate percentage reductions. My simple estimate takes a constant reduction over 80 years, which is probably a bit on the high side. If you assumed that emissions were going to decline anyway over the second half of this century, the effect of the policy would be reduced, perhaps by half.

Those three factors, taken together, would account for the discrepancy in the two estimates. I don’t claim that I’ve got them exactly right and there may be points I’ve missed. But for someone like Bolt to pontificate on a subject like this, when he is incapable of avoiding or correcting even the most absurd errors, brings to mind Matthew 7:3-5.

A couple of minor points

First, Bolt’s behavior in crowing about a minor mistake on my part, while ignoring his own total absurdity, is par for the course among delusionists. A while back, there was a major scandal (it even got a “Gate”) over the fact that the thousand-page IPCC volume on the impact of climate change included an erroneous claim about Himalayan glaciers. But delusionists get away with far sillier stuff on a daily basis. For example, Christopher Monckton, until recently Bolt’s favorite source of scientific evidence[1] used Gavin Menzies 1421 to argue that the retreat of polar icecaps was nothing new, since the great Chinese fleet had taken the Arctic route on the return journey from discovering America.

Second, as Cut and Paste notes, I said when I took up the Climate Commission position that I’d try to refrain from polemics with people like Bolt. I haven’t stuck to that as well as I might have, and now I think it’s totally pointless. So, from now on, I plan to give as good as I get and, if possible, a bit more.

fn1. He was, after all, Thatcher’s science adviser, if only in bizarro world.

41 thoughts on “Motes and beams

  1. Kris asks: “ever made a dollar that was not off the back of hardworking Mums and Dads taxes?”

    Kris, you are asking this question on the wrong media site. You should ask this question of Bolt’s accountant and Bolt’s ultimate boss’ accountant and your own accountant, assuming you have one. Enron’s accountants, the proverbial Wall Street bankers’ accountants, Obeid’s accountants ………….. are other relevant addresses.

  2. “ever made a dollar that was not off the back of hardworking Mums and Dads taxes?”

    Actually Kris, I wouldn’t be surprised if I’ve made more private sector dollars than you have. I’m a well-selling author (last book translated into 8 languages), columnist, investor, consultant etc. If you want to play BSD, send me your last tax return and I’ll compare notes.

  3. Prof Q, there’s another problem with your maths… it is premised on the idea that the policy will actually reduce emissions by 160 million tonnes per year even though the modelling of it suggests that’s not the case. The modelling released with the carbon-price predicted that emissions in Australia would actually increase until at least 2026. It’s true that there might be millions of tonnes of “offsets” bought, but as these aren’t covered by a cap it’s pretty hard to say the result is a net-reduction in emissions. So although you’ve done the maths better than Bolt, and I agree with you on most things, his number might be closer to the ‘truth’ when all is melted and washed away…

  4. @alexiinbogota

    I can’t comment too much on this as the Climate Change Authority is undertaking some new modelling on these issues in the course of recommending caps and targets for 2020. But I agree these are serious concerns that need to be addressed.

  5. That 160 Mt emissions reduction assumes ‘business as usual’ which if I recall was 1.2% compound growth. Year 2000 emissions were 558 Mt so 5% of that is 28 Mt. In other words the real 2020 target is just 530 Mt which is about where I think we’re at now. In other other words bugger all.

  6. Thanks for so quickly working me out. You have me pegged right,my intelligence is not in the same league as those who gave us comments 1 and 4 on this thread.
    But obviously you have the wit to appreciate the depth of Adams and Garry’s contributions to this blog. It’s beyond me.
    Go Flash Go !!

  7. Kris, I don’t think you’ve added anything except to point out the bleeding obvious. John works at a university. Adam and Garry were expressing good-natured support. What’s to think about? You contributed a snide remark about someone you don’t know – based on what? IIRC, in the article you’re referring to, John was not disparaging “Mums and Dads” whatever the hell that could mean anyway, he was disparaging those who would falsely seek to use the phrase “Mum and Dad investors” to garner public support. It is not anyone here who is playing you for stupid – it is the newspapers columnists you choose to read.

  8. “It is not anyone here who is playing you for stupid – it is the newspapers columnists you choose to read.”
    Could not agree more Nick! And these columnist get published, according to the Limited News line up last night at the ABC, because freedom of speech allows anyone to sprout any lies or blatant commercial interests, because people pay for it and consume such ‘fast news’. Thus, the ‘Kris’stans’ in this world suffer the intellectual equivalent of obesity and are highly adviced to pay more attention to their extent and selection of media consumption, otherwise it may render their lifestyle and world they live in unsustainable.

  9. @TerjeP

    I suspect the “he said she said” style saga will be like some hill billy feud

    Awesome.

    Take back what yer said about mah maw, yew gosh-durn, cotton-pickin’ Liburmah-tarian! And geddawf mah lay-und!

  10. Well the standard is still above that of Gerard Henderson against whomever (most recently, Mark Latham).

  11. Following a recent comment from Tim Flannery it has become pretty clear in my mind on how global warming will progress. Flannery pointed out that a key element in the process is the amount of moisture in the atmosphere. Spot on.

    So Global Warming at this stage does not appear in the form of day time temperature so much as it does in humidity. With the warming oceans humidity rises in the tropical band which extends further poleward. Tha humidity releases its energy and moisture content in the increased storm activity and at night. The temperature rise is most evident in the average night time temperature. The other dynamic, I believe, is in the rate of atmospheric circulation, ie evidenced in the Hadley Cell performance.

    The Polar ice is under attack in the Northern Hemisphere from intensified atmospheric activity largely, and in the South by intensified ocean current activity. Each affecting the weather in different ways, the common factor being an increased movement of colder water and air towards the equater to provide a seamingly contradictory array of weather events.

    I had to endure a tyrade from a Monktonite who claimed to have temperature records going back to the year dot, And I have no doubt that he did. But it was in pondering his claim that I realised the significance of Flannery’s comment. The increased energy in the atmosphere is in the form of humidity which does not necessarily affect the daytime temperature, but it does have a huge impact in the rarely mentioned night time temperature. Where it is most dramatically and visibly evident is in weather event intensity which even the most indolent of news feeds are recognising as being a significant change from the past, ………………. Bolt excepted.

    As they say in aviation, first and foremost concentrate on flying the plane, don’t be distracted by the blaring alarms. The Bolts, Joneses and Monktons are nuisance alarms announcing the presence of stupidity in the system. Turn them off.

  12. @BilB
    It’s a common fallacy that global warming must result in steadily higher atmospheric temperatures – disappointing that understanding of basic physics is so poor.

    Increased retained energy in the atmosphere causes increased oceanic evaporation, and is also expressed as more energetic weather – furthermore, laws of thermodynamics determine that energy must flow from hotter to cooler regions, ie, from equatorial towards polar, and this explains the apparent shift of seasonal weather patterns to higher latitudes experienced in both northern and southern hemispheres.

    We (warmists) have been understandably cautious about attributing local changes in weather to global warming, but maybe it’s time to be a little bolder, and to start pointing out changes which are consistent with warming. The southward shift of Qld’s monsoon is a good example.

  13. @Sancho
    ” Yobbo’s easy to mock, but he’s not actually a troll: he represents the quality of thought that underpins the IPA……He actually comes out to comment at blogs where the majority opinion is against him”

    Oh please – providing “quality of thought”? So far 10 entries on this thread, all throwaway lines delivered with contempt, like you hear shouted out in the front bar.

    And his bravery? Obvious answer is that some people just get their rocks off on verbal biffo, hence no attempt at a coherent argument.

    @John Foster
    My previous request for you to clarify apparent contradiction is withdrawn. I now see that you were quoting the Yobbo but didn’t include quote marks, so it appeared to be your own view. Apologies.

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