Hopefully people interested in the blog wars have been alerted to the ongoing climate change “debate” between George Monbiot and Ian Plimer. If not, the best place to start is probably Monbiot’s blog itself (with several posts on the topic already). Greenfrye and Tamino also have some ongoing commentary, so have fun catching up on what’s going on.
Unfortunately, round 1 consisted of Plimer dodging Monbiot’s questions which ask Plimer to defend certain indefensible statements in his book “Heaven and Earth.” Maybe Plimer just “wanted to go first” so I’ll give him the benefit of the doubt, but his own set of questions intended for Monbiot are quite revealing about his intentions.
As most commenters have suspected, these questions are all ill-posed or have nothing to do with the attribution or prediction of future climate change. In most cases, if an answer is even possible, it’s not very meaningful information. It’s just a distraction, something Monbiot wanted to avoid in his debate conditions. They’re an obvious way to let Plimer set the tone of the “debate” by making it sound scientific to readers who know nothing about the subject. I’m not going to “answer them” in much detail but just to address the tactics behind a handful of them I am creating a post. I will open up commenters to address some other ones.
1. From the distribution of the vines, olives, citrus and grain crops in Europe, UK and Greenland, calculate the temperature in the Roman and Medieval Warmings and the required atmospheric CO2 content at sea level to drive such warmings. What are the errors in your calculation? Reconcile your calculations with at least five atmospheric CO2 proxies. Show all calculations and justify all assumptions.
It is rather strange why Plimer requests agriculture as a proxy for paleotemperature (and what’s stranger is what this has to do with anything). The answer about the error is simply that it will be “large” and will not be indicative of global temperatures, even if temperature is the dominant climatic variable picked up by changes in vines and crops. What’s more interesting is the statements about Carbon Dioxide. Plimer plays an interesting trick here and assumes that these climate changes were in fact caused by Carbon Dioxide (which they weren’t). The question about CO2 content at sea level is a hypothetical question (how much CO2 would it take to cause the climate change?), but then he asks Monbiot to reconcile this with observations (I’m not sure why he needs five, I’d just use ice core records here as a starting choice.) But what if CO2 didn’t cause those warmings? In that case, Monbiot could answer the hypothetical first question, but there would be nothing to answer for the second part of the question since the justification itself would be expected to be void. It’s like if someone asked me how much the globe would cool if we removed all the CO2 from the atmosphere (which is an interesting question) but then asking me to back that up with proxy data, as if this actually happened before. Even to answer the first question about “CO2 content” would include some caveats since it’s the *change* in CO2 that matters for driving warming, not the absolute content, and it’s the fractional increase (not the absolute increase) that matters and so you’d need to know the baseline value of CO2. This is not difficult to get from proxies (and not much different from pre-industrial values) but the question as stated makes little sense. Furthermore, CO2 is well-mixed in the atmosphere and so there’s no reason to confine the question to sea-level, especially since CO2 in the upper atmosphere matters significantly for radiative transfer.
Tabulate the CO2 exhalation rates over the last 15,000 years from (i) terrestrial and submarine volcanism (including maars, gas vents, geysers and springs) and calc-silicate mineral formation, and (ii) CH4 oxidation to CO2 derived from CH4 exhalation by terrestrial and submarine volcanism, natural hydrocarbon leakage from sediments and sedimentary rocks, methane hydrates, soils, microbiological decay of plant material, arthropods, ruminants and terrestrial methanogenic bacteria to a depth of 4 km. From these data, what is the C12, C13 and C14 content of atmospheric CO2 each thousand years over the last 15,000 years and what are the resultant atmospheric CO2 residence times? All assumptions need to be documented and justified.
The whole point here is to sound smart. There’s nothing here remotely relevant to what Monbiot wanted to debate. One can certainly pull up tree ring or ice core data to get C13/C12 ratios as a time-series, or (probably more relevant) CO2 concentration in the atmosphere whose fluctuations will tell you something useful about net emission/uptake and whether the carbon cycle has been perturbed, as well as residency time. We don’t know emissions from every individual source and there’s also not much point in throwing the “From these data…” connection since certain proxies record CO2 content in the atmosphere to pretty high accuracy without knowing where it came from.
From first principles, calculate the effects on atmospheric temperature at sea level by changes in cloudiness of 0.5%, 1% and 2% at 0%, 20%, 40%, 60% and 80% humidity. What changes in cloudiness would have been necessary to drive the Roman Warming, Dark Ages, Medieval Warming and Little Ice Age? Show all calculations and justify all assumptions.
Changes in cloudiness at 0% humidity indeed!!
Obviously some of these situations are unphysical and so preclude any realistic calculation and cloud change is generally thought to be a feedback. It also depends not only on cloud amount but distribution of cloud type, as changing high clouds and low clouds (or for example one could decrease the area coverage but increase the cloud top altitude) would have different, even competing effects.
One crude estimate presented by Dennis Hartmann is his book “Global Physical Climatology” is that the fractional area of cloud cover is about 50% and has a net -20 W/m2 impact on the energy balance, and thus the partial derivative of the net radiative energy input at the TOA with respect to the total fractional area of clouds would imply that a 10% change in cloud fraction would either offset or double the RF for a doubling of carbon dioxide.
From ocean current velocity, palaeotemperature and atmosphere measurements of ice cores and stable and radiogenic isotopes of seawater, atmospheric CO2 and fluid inclusions in ice and using atmospheric CO2 residence times of 4, 12, 50 and 400 years, numerically demonstrate that the modern increase in atmospheric CO2 could not derive from the Medieval Warming.
Bascially in an overcomplicated way, Plimer is asking to show that the modern rise in CO2 is not a feedback from medieval warming. This is probably some offshoot of the whole “CO2 lags temperature” line. One issue here is that the perturbation lifetime of CO2 is different than the “lag time” which occurs as a response to warming. Even then no one expects an abrupt decadal scale rise of CO2 centuries after the event, which isn’t even what occurred in the glacial-interglacial cycles, which were considerably larger in magnitude and spatial extent then the MWP. The rate of change is today of CO2 is orders of magnitude larger, and the absolute concentration is also much higher than the whole ice core record show and even much longer. We also know that today’s CO2 increase is anthropogenic because CO2 is going into the ocean (ocean acidification, duh) not going out and isotopic signatures of light and heavy carbon changes.
From the annual average burning of hydrocarbons, lignite, bituminous coal and natural and coal gas, smelting, production of cement, cropping, irrigation and deforestation, use the 25µm, 7µm and 2.5µm wavelengths to calculate the effect that gaseous, liquid and solid H2O have on atmospheric temperature at sea level and at 5 km altitude at latitudes of 20º, 40º, 60º and 80ºS. How does the effect of H2O compare with the effect of CO2 derived from the same sources? All assumptions must be justified and calculations and sources of information must be shown.
I laughed very hard at this last one. It’s all a complete mess and meshes together many different problems. There’s absolutely no relation between what we burn for example and the absoprtion properties of water vapor or CO2 (and by the way, for CO2 you want to look near 15 microns and the unsaturated bands on either side). There’s also essentially no effect from water vapor from those sources since it precipitates out quickly and is thus not a climate forcing. This is of course in the gas phase, I’m not sure what information he wants about liquid or solid phases. All togther this is jumbled up nonsense and shows that Plimer is intentionally trying to mislead others.
For other of Plimer’s questions, I’ll let commenters tackle those. It’s unfortunate that skeptics wanted to “debate” for so long and now have this clown representing them, who is just throwing up sciency-sounding but intellectually vacuous smokescreens.
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Excellent! Thank you for this. With your permission Monbiot should use this in his “answer” to Plimer. I note you very politely passed on some of the more egregious idiocies; “From first principles…” indeed! “I am a pompous ass” is all that says.
Response– Anyone can use this with citation, although it’s obviously not comprehensive enough for a full posting. Way too much for a blog posting. It would take a book describing the scientific problems, and much more importantly, the psychology behind Plimer’s tactics.– chris
” It would take a book describing the scientific problems, ”
But clearly stating that fact has value, so thank you.
” the psychology behind Plimer’s tactics”
As in how much desperation vs calculation? There’s a well with no bottom …
We also know that the CO2 is anthropogenic from the decreasing oxygen concentration due to combustion.
Wow. This is such a visible-from-orbit mess, such an absolutely perfect exhibition of the denier mindset that it reads like the work of an incredibly skilled satirist.
The most accurate thing in this blog entry is the observation, “They’re [the questions are] an obvious way to let Plimer set the tone of the ‘debate’ by making it sound scientific to readers who know nothing about the subject.” That’s precisely the denier game plan. Talk to experts in public, but play to the audience of mainstream voters and consumers who happen to pass by the discussion. It worries me that so many of the experts don’t seem to grasp this basic issue, and therefore end up helping the deniers bamboozle the bystanders. Is it any wonder that here in the US the public views of climate change are so depressingly behind the times?
We could use more debates. I’d like to see Steve McIntyre vs Michael Mann, or Wegman vs Mann.
Let’s here him and the rest of the RealClimate team defend these new statistical measures they came up with. Why do they cut off proxies, or change their values to show the ‘correct’ behaviour? Is that valid science?
And while we’re at it, it would be great to hear Palin (sarah that is) debating Putin on the role of China in reducing black carbon debosition in the arctic.
In my view, the main reason why we know that the CO2 is ours is because we have emitted much more (about double) than the increase in the atmosphere. Therefore, the net natural contribution has to be negative (sinking what we emitted and isn’t in the atmosphere any more).
Question 1 is kind of answerable:
Since vineyards in UK and Sweden go farther north than in Roman and Medieval time, one can estimate (as opposed to calculate) that climate today is warmer than it was then.
An error in this estimate could arise from be disregarding technologic and sociologic differences in logistics, viticulture and wine market demand of different civilizations. The climate skeptic consensus is to neglect this error.
The estimate has nothing to do with CO2 at sea level, but hints at a higher atmospheric CO2 content today, as e.g. calculated by Svante Arrhenius in “On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground”: Philosophical Magazine and Journal of Science (5th series) 41, 237-275, 1896. This is validated by the Keeling curve and ice core samples.
Is this the same Monbiot who concluded that using offsets in climate change legislation would mean a larger reduction in emissions for the developing world than the “developed” world?
Or are there actually two Monbiots engaged in climate science?
The natural proxies including species distribution and farming conditions we have now have been observed with more precision than anything going on in the Medieval Warm Period, so the error for that period from natural proxies has to be far higher than for similar proxies now
By the way, I have been collecting stuff, mainly from here but also tamino, greenfyre, etc. and putting it with the questions here
It’s transcluded near the end, meaning that someone could edit this and it would show up in the calling page. I started out numbering using wiki ordered lists and moved to h4 tags, because that way each question is a separate, editable section. that’s a wiki anyone can join (or even edit anonymously, tho your IP is logged).
The very end of the debate page explains why i picked that place and this manner and why i’m collecting the responses to begin with.
Excellent work. I’ve been hoping that someone might do this, and I am sure that it’ll have a significant contribution to make, along with Chris’s and Tamino’s work, in exposing Plimer for what he is doing.
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Q1. As the atmospheric CO2 content was for all practical purposes constant during the Roman – Medieval periods any change in Western European temperatures that resulted from this that led to global temperature changes this imply a very large climate sensitivity. Either:
A. the Western European temperature changes in the Roman – Medieval periods had very little effect on global temperatures – so this question is irrelevant
B. Climate sensitivity is very large – so we are all going to die!
C. the Western European temperature changes in the Roman – Medieval periods had nothing to do with CO2 changes – so this question is irrelevant
Good job here (RC did well too, but you were there first!)
Thought you might be interested in my war of words with ABC regarding the Plimer “Unleashed” piece. It turns out that section 4 (covering opinion content) of ABC’s Code of Practice requires ABC to take “reasonable steps” to ensure factual accuracy in opinion content. Incredibly, the “Unleashed” editors, supported by ABC Audience Relations, appear to be asserting that that rule does not apply to them.
> It’s unfortunate that skeptics wanted to “debate” for
> so long and now have this clown representing them
Your argument is mistaken. There is no consensus among global warming skeptics, and there cannot ever be.
Some believe AGW is a hoax, others think warming is going to be mild and beneficial, others say it’s mostly natural, others refuse to take a stance before enough evidence (in their judgment) is collected.
Actually, given that there is a scientific consensus towards AGW, you are guaranteed to find all sorts of nutters and outright crazy people in the “skeptical camp”. This of course says nothing in favor of the truthfulness of the AGW arguments, or against it.
Response– I’ve only distinguished between “sloppy” and “really bad” and “outright lies” in my skeptic categorization. So maybe it was unfair to classify them all together– chris
Plimer, or Singer, or anybody else, they will never represent anybody else but the people that believe in what they are actually saying.
Give me global warming anytime.
I have a question that I cannot find an answer to.
What percentage of the worlds Co2 emission are man made.
I would like the answer from someone who is not a sceptic.
If I remember correctly, there’s a decently comprehensible sketch in the video under the “Mechanics of GCC” tab on this page:
The author of the video definitely doesn’t fall into the skeptic camp.
@manfred: If I remember correctly, there’s a decently comprehensible sketch in the video under the “Mechanics of GCC” tab on this page:
The author of the video definitely doesn’t fall into the skeptic camp.
Having not studied for 45years but always been interested in certain topics,I find the argument against AGW compelling.The crux of the arguments seem to be that CO2 is the villain.I cannot understand how a gas,necessary for all life,heavier than air,with a concentration of about 400parts per million can be so powerful.I can appreciate laboratory experiments showing radiation properties of CO2 regards infra red,but because this a logarithmic relationship,surely even a quadrupling of CO2 concentration it still would not do the job.Why do market gardeners pump CO2 into their greenhouses to get better yields and more nutritious plants?
Anthony: many compounds can be powerful at very low amounts. Fill your body with 400 ppm arsenic trioxide, and you die. Same goes for selenium. And yet, arsen and selenium are absolutely vital for life. Besides that, 400 ppm of something in the air may be a low concentration, but is actually a HUGE amount. And we should be happy it has an effect, or it would be really cold on earth.
The greenhouse effect is different from a greenhouse. Moreover, a greenhouse has as an express aim to keep the contents warm. Finally, do remember that in a greenhouse the gardeners keep on adding all kinds of nutritients. CO2 would be completely useless if they would not add large amounts of fertilizer, too.
If I understand correctly, then on one hand, we’ve got you, Anthony, with your “CO2 doesn’t reflect heat back to earth” theory. Whereas on the other hand, we’ve got every scientist on earth saying the opposite. (Whether they’re in agreement with the larger AGW/climate change thing, I think they’re all signed up to the idea of CO2 reflecting heat back to earth.)
No offence, Anthony, but I’ll go with the scientists for now.
Response– Not to be anal, but the greenhouse effect does not operate by “reflecting heat” but rather by absorption and re-radiation, and thereby allowing the planet to radiate to space at a temperature colder than the surface. You can see CO2’s effect by any spectra taken from space– chris
Thanks Marco but the elements you mentioned are poisons even at very low levels,CO2 is not toxic.If long wave radiation is emitted from the Earth’s surface the probability of interaction with such a sparse gas seems pretty remote.For any radiation to be reflected back surely it’s almost directly proportional to the incidence of that tiny molecule in the Troposphere.So the amount returned in the direction of the surface by orthogonal interaction cannot be greater than 0-004% assuming CO2 @ 400ppm.The other factor is that most radiated heat is absorbed by water vapour which by rain returns the heat back to Earth.While I don’t completely deny that there could be global warming,CO2 cannot be the vehicle,water vapour yes.Every gallon of petrol or diesel produces one gallon of water,which is spewed into the atmosphere in the form of water vapour.Similarly coal,wood,gas etc produce practically weight for weight water emissions.You are also misinformed on the action of CO2 in Market gardening,it will become more common soon.CO2 is 50% heavier than air so naturally it is more abundant in the lower atmosphere where it combines with water vapour to form unstable Carbonic acid.Plankton and plants recycle.
Response– Anthony, you are very confused. It’s hard to really reply to this when every pretty much every single sentence is fundamentally wrong. Please read a textbook on atmospheric radiative transfer and the greenhouse effect– chris
Allow me to add that ANY compound is toxic, in the ‘right’ amounts. Drink 5 liter of water in an hour, and you likely die. We need insulin in the right concentrations at the right time, or it’s toxic. Same goes for CO2.
Thank you for your reply and comments,it appears I am quite thick so I will get my reading glasses on and acquire the literature.
Just found a puzzling link in the “possibly related posts” section of your page at https://chriscolose.wordpress.com/2009/08/12/ian-plimers-questions-to-george-monbiot/
Search “Global Warming Myth” – it should take you to the link, which leads to a denial site – odd, since your posts seem focused on dealing with, well, REALITY . . .