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Curve manipulation: lesson 2

Filed under: — stefan @ 14 June 2007

Two weeks ago, we published the first lesson in curve manipulation taught by German school teacher and would-be scientist E.G. Beck: How to make it appear as if the Medieval times were warmer than today, even if all scientific studies come to the opposite conclusion. Today we publish curve manipulation, lesson 2: How to make it appear as if 20th Century warming fits into a 1500-year cycle. This gem is again brought to us by E.G. Beck. In a recent article (in German), he published the following graph:

Notice how temperature goes up and down in beautifully regular cycles since 800 B.C.? At the bottom, they are labelled “Dansgaard-Oeschger cycles” – this refers to the Dansgaard-Oeschger events found in Greenland ice cores during the last Ice Age (but not during the last 10,000 years), about which there is a serious scientific discussion whether they are paced by a 1500-year cycle (see my paper in GRL). Beck’s curve shows a warm phase 400 BC and the next one 1200 AD – that’s 1600 years difference, so it just about fits. (I’m not endorsing his curve, by the way, I have no idea where it comes from – I’m just playing along with it for the sake of the argument). So the next warm phase should be in the year – oooops… 2700 or 2800? Hang on, how come it looks like the current warmth fits so nicely into the cycle? Shouldn’t we be right in the coldest phase? Now I see it… two little lines across the x-axis indicate that the axis has been broken there – tick-marks after the break are in 200-year intervals and before the break in 400-year intervals, and there’s also a gap of 200 missing years there. So that’s how we make the current global warming fit past climate cycles – it’s so easy!

p.s. Beck appeared on German TV last Monday, after the “Swindle” film was shown, and he is announced to appear on the program “Report München” in the first channel of public German TV next Monday (18 June), to educate the viewers about another of his fantasy graphs, namely his CO2 curve. It promises to be a must-see for friends of the unintentionally farcical.


346 Responses to “Curve manipulation: lesson 2”

  1. 151
    Ray Ladbury says:

    Re 150: Barton, a letter like that guy’s letter gives me a chance to paraphrase Vonnegut: “He teaches science like my ass chews gum.”

  2. 152
    tamino says:

    Re: #142 (Agnes Witter)

    I too salute your willingness to oppose misinformation about this important issue.

    I suggest you send the following letter to the editors of the paper. Please alter it to suit your own personal preferences, and submit it under your own name.

    ====================
    A recent letter to the editor about the behavior of carbon dioxide in our atmosphere is completely wrong.

    When the author makes such statements as, “carbon dioxide always falls due to gravity,” and “The carbon dioxide cycle is a one-way street from the oceans, carried by winds, which calm over land and allow all carbon dioxide to fall on the ground” he reveals his ignorance of the behavior of gases in our atmosphere. Carbon dioxide is a well-mixed gas whose concentration is roughly constant throughout the lower atmosphere (the troposphere, about the lowest 10 km of our envelope of air, thicker in the tropics and thinner at the poles). The constant mixing of gases in the atmosphere is maintained by the process of convection. Even if such convection were not present, the “scale height” (the height at which the density of a gas is reduced to half its sea-level value) for carbon dioxide would be 4 km, compared to about 6 km for most atmospheric gas.

    Carbon dioxide concentration is monitored at a large number of stations throughout the world, many of which are at high altitude (data can be obtained from the World Data Center for Greenhouse Gases, http://gaw.kishou.go.jp/wdcgg.html). The altitude-dependence suggested by the letter’s author is contradicted by direct observation.

    The most naive error of the author is miscalculating the molecular weights of atmospheric gases. He states, “Carbon dioxide is … a compound of carbon bonded to oxygen atoms with a combined atomic weight of 14.5,” when in fact the molecular weight of carbon dioxide is 44 (atomic mass units). He then states, “Air is 78 percent nitrogen with a weight of 14,” quite ignoring the fact that atmospheric nitrogen is a molecule of two nitrogen atoms, with weight 28.

    The letter-writer claims to be a former science teacher. How sad that our children were taught this subject by someone who is so woefully ignorant of science, but still feels qualified to state his mistaken beliefs as fact!

    Perhaps the greatest pity is the journalistic irresponsibility of the editors of this newspaper, who seem not to know the difference between fact and foolishness, and apparently cannot be bothered to check the accuracy of the writer’s claims. The most basic investigation would have quickly revealed that the letter is utter nonsense, and should never have seen the light of day.
    ====================

  3. 153
    nicolas L. says:

    Hello Agnes

    I’m sure a lot of people will be more qualified here than me to answer properly, as far as Iâ??m a biologist and atmospheric physics sometimes get far out of my reach :). But you can learn a lot on atmospheric composition and gas mixing by reading those few articles: that should give you a good bases to answer your teacher (thank god heâ??s not teaching my children)

    http://en.wikipedia.org/wiki/Carbon_cycle
    http://earthobservatory.nasa.gov/Library/CarbonCycle/carbon_cycle4.html/
    http://en.wikipedia.org/wiki/Carbon_dioxide
    http://en.wikipedia.org/wiki/Earth%27s_atmosphere
    http://en.wikipedia.org/wiki/Atmospheric_chemistry

    “Carbon dioxide is carried aloft by natural means of strong updrafts over the oceans, volcanic eruptions and great forest fires due to extremely hot updrafts, putting carbon dioxide into the stratosphere where the jet stream winds can hold it for years” If you look at the carbon cycle, you’ll notice one of the main sources for CO2 release in atmosphere is respiration and decomposition of plants and animals (so if the CO2 we expire can go in the atmosphere, a power plant release can certainly do). Another thing is that CO2 concentrations in the atmosphere are going up and up since the last 150 years (from 280 PPM in pre-industrial era to 379 ppm today), without any major change neither in the natural sources of CO2, nor in the natural CO2 sinks. So where does this CO2 comes from? I’m afraid not from a hatâ?¦

    “Gravity rules that only lighter gases, such as helium and hydrogen, can rise in the air around us. Oxygen and carbon dioxide must fall to the ground, and that is the reason life exists on land.” Hmmm, You should try to explain him atmosphere is pretty well mixed and that you will find approximatively the same components in the same proportions all along of the homosphere (from 0 to 100 km high), water vapour excepted. Thank god for us, gravity is not the only element that enters into account when speaking about the composition of something.

    “Even strong weather on land cannot provide an updraft to carry carbon dioxide from cars above the clouds to reach the stratosphere and add to the greenhouse effect of carbon dioxide in the stratosphere that traps in heat to cause global warming.” As far as I get it, CO2 doesnâ??t have to climb through the stratosphere (which it does anyway) to be a GHG, it already is in the low atmosphere, with the same consequences.

    “The carbon dioxide cycle is a one-way street from the oceans, carried by winds, which calm over land and allow all carbon dioxide to fall on the ground. It cannot happen in reverse.” If carbon cycle was a one way street, it wouldnâ??t be a cycle :). The principle of a cycle is to have a dynamic equilibrium between the different states of an element. The way he describes it, CO2 should have disappeared from atmosphere a long time ago now.

    “Land-based emissions of carbon dioxide can rise briefly due to heat expansion until the heat is gone. Carbon dioxide goes a short height, then goes sideways until it becomes invisible and falls on the ground.” Someone more competent should comment about that, but this really sounds far from a good scientific analysis (CO2 becoming “invisible”, thatâ??s a nice story I had never heard before). You could also answer CO2 has an average life time of 100 years when released in the atmosphere before it’s captured by a terrestrial or oceanic carbon sink (I donâ??t think it can be considered as a short time anyway)..

    “Students can do a simple science experiment by filling up balloons with carbon dioxide and letting them go in a field.” Of course what he misses there is that CO2 trapped in a balloon won’t ever have the chance to get mixed with the other atmospheric gasesâ?¦ Therefore it doesn’t reproduce any kind of natural conditions; therefore it’s no scientific experiment.

    Another document thatâ??s really good to learn about the effects of GHG: the IPCC 4th assessment report, published a few weeks ago. You can read the summary for policy makers for a start, youâ??ll find all the data you need about concentrations of atmospheric CO2 you need.
    http://ipcc-wg1.ucar.edu/wg1/wg1-report.html

    Ok, hope this will help, tough I think there are lots of people here abble to answer more accurately than I did. Keep up with the fighting spirit.

  4. 154
    Timothy Chase says:

    Agnes,

    For something as small as a carbon dioxide molecule, the simple turbulence of the slightest breeze or for that matter kinetic motion due to heat is certainly more than enough to keep it well-mixed in the atmosphere. If it weren’t, plants wouldn’t grow up the side of mountains up to where it is simply too cold for them to survive. Ice droplets are denser than air, but we have clouds, including cirus clouds, where the droplets have frozen to ice.

    Mass is a function of density and volume, but while volume increases as the cube of the scale, surface area increases only as the square, thus the ratio of surface area to volume increases as something becomes smaller. If you drop a man off a fifty story building, things won’t be pretty. If you drop an ant off the empire state building, it will walk away. How much smaller is a molecule than an ant?

    The smaller something is, the more the turbulence and then kinetic motion matters. But once we get to water vapor and carbon dioxide, we aren’t talking about droplets anymore: we are talking about individual molecules. Unlike water vapor, carbon dioxide will never condense to the point that it consists of a liquid, even the smallest of droplets – except under very extreme conditions. In fact, it goes from solid to gas with no intermediate state of liquid at the natural temperature and pressure ranges encountered on earth.

    I can’t put it delicately: this guy is so ignorant of science and so lacking in common sense than just about anyone that I pick off the street would think his arguments absolutely bizarre.

  5. 155
    Steve Reynolds says:

    ray ladbury> Steve, I didn’t address any accusations of overstatement, because you didn’t make them yet. And if Gore is guilty of overstatement, he should be corrected.

    The overstatement is implied in the same graph (that modern temperatures would increase with CO2 concentration with the same sensitivity implied in the graph).

    Ray> The other thing you don’t seem to acknowledge is that scientists in no way refer to Al Gore as an authority to make their case.

    I disagree. Maybe not as a scientific authority, but some endorse AIT to make their case to the public.

    Ray> The denialist community gleefully cites Beck when it suits their purpose. Shouldn’t that bother you?

    Yes, it does. That is how this series of my comments started – I condemned Beck’s graph.

  6. 156
    Jim Galasyn says:

    Re the Agnes letter in 142:

    I remember a bitter debate on Usenet back in the day. The question was whether gases of different molecular weights would “settle out” at STP as suggested by the science teacher.

    People pointed out that you can pour heavy or cold gases out of a dewar, and they’ll stay on the floor. But of course, this is a transient state. Because we’re talking about gases, they eventually mix completely — hence the idea of partial pressure.

    I imagine that if you started freezing out the atmosphere, then you’d see stratification, but then we’re not discussing gases anymore. Cryogenic worlds like Titan and Pluto probably do show stratified layers on the surface, but not in their atmospheres.

  7. 157
    Ray Ladbury says:

    Steve, why do you suggest that modern sensitivity to CO2 will be substantially different from sensitivity for similar CO2 concentration in the past. Moreover, I don’t remember Gore making any claims about sensitivity in AIT.

    There is a huge difference between endorsing the efforts of a private citizen to educate people about a scientific issue and citing a nonscientist (and a fraud, as it turns out) as a scientific authority, would you not agree? Merely condemning the graph is not sufficient. What Beck has done here is every bit as serious as the fraud by Hwang-Woo Suk–a deliberate (if ham-handed) attempt to mislead people about a scientific matter.

  8. 158
    Chuck Booth says:

    Re 156
    There is a similar, long standing debate regarding compressed gas mixtures in a cylinder (e.g., air in a SCUBA tank) – some people think that over time the gases will stratify according to their density, and so should be remixed by rolling the cylinder (shake those gases up!), or gentle heating (e.g., with a lamp) before using the tank (http://www.newton.dep.anl.gov/askasci/chem03/chem03325.htm ). The notion of stratifying gases in a closed cylinder always struck me as violating Dalton’s Law of Partial Pressures and the second law of thermodynamics. It is my understanding (I’m not a physicist!) that while gases of greatly different density may stratify under some conditions ( e.g., in mines – http://www.worksafesask.ca/files/sask_labour/mine_manual.pdf.) the reason the component gases in air in sealed cylinder (compressed, or not) don’t stratify is that their density differences are small relative to their kinetic energy. Is this essentially correct?

  9. 159
    Agnes Witter says:

    WOW, thank you all so much for your rapid replies. I not only get a letter already composed for me but an excellent education to boot.

    What more could an old gal ask for.
    hugs to you all.

  10. 160
    Timothy Chase says:

    Regarding Al Gore and his documentary “An Inconvenient Truth,” Ray Ladbury (#149) wrote:

    The other thing you don’t seem to acknowledge is that scientists in no way refer to Al Gore as an authority to make their case.

    Steve Reynolds (#155) responded:

    I disagree. Maybe not as a scientific authority, but some endorse AIT to make their case to the public.

    I know I would endorse it – with a caveat or two. It is highly educational, deals with an important subject, does a beautiful job artistically of blending the personal and the global and historical, and despite its topic is quite positive in its message. And at a certain level, it even manages to deal with what it means to be human. Currently I know of only just one error. It was implicit in how one might reasonably interpret a given graph as suggesting a climate sensitivity greater than what it actually is, suggesting 10 C rather than 3 C. I wouldn’t blame it on him per se or on the viewer. But preferably someone should have spotted what the graph was suggestive of when naively interpreted – if only to prevent dishonest ideologues from taking advantage of this omission as a quick and easy means of character asassination and ad hominem attack so as to dismiss the film as vilest propaganda.

    Wouldn’t you agree Steve?

    With regard to other omissions, they were basically due to lack of time. For example, one couldn’t possibly cover all of the positive feedbacks that are involved in climate change. The one other “problem” you have pointed out regarding a large lag-time with respect to natural global warming (where positive feedback begins with a rise in temperature) is for all intents and purposes irrelevant with respect to manmade global warming which has been initiated with a high rate of CO2 emissions, and consequently takes place at a substantially higher rate.

  11. 161
    Chuck Booth says:

    Re 158
    Should anyone care, the link I provided doesn’t work. This one should:
    http://www.worksafesask.ca/files/sask_labour/mine_rescue_index.htm
    The document is: Saskatchewan Mine Emergency Response Program Mine Rescue Manual

  12. 162
    Steve Reynolds says:

    Ray Ladbury> Steve, why do you suggest that modern sensitivity to CO2 will be substantially different from sensitivity for similar CO2 concentration in the past. Moreover, I don’t remember Gore making any claims about sensitivity in AIT.

    See 160 (Timothy Chase). Also, think log response, not linear.

    Ray> There is a huge difference between endorsing the efforts of a private citizen to educate people about a scientific issue and citing a nonscientist (and a fraud, as it turns out) as a scientific authority, would you not agree?

    So if people only endorse Beck, rather than cite him, then everything should be OK acording to that logic? Assuming that no one is a fraud.

    Ray> What Beck has done here is every bit as serious as the fraud by Hwang-Woo Suk–a deliberate (if ham-handed) attempt to mislead people about a scientific matter.

    That may or may not be true. That depends on Beck’s motivation, of which I am not aware.

  13. 163
    Eli Rabett says:

    158 Chuck, it is true that mixtures settle in compressed gas cylinders, although usually you need a larger difference in mass than the 4 amu between CO2 and N2. They also need time to mix esp when there is little convection.

    This leads to such odd behavior as putting a large gas cylinder into a hot foot bath to warm it up a bit and remix, or leaving a new mixture to sit overnight and mix.

  14. 164
    James says:

    Re [“Even strong weather on land cannot provide an updraft to carry carbon dioxide from cars above the clouds to reach the stratosphere…]

    In addition to what others have mentioned, also note that those updrafts are sufficiently strong to carry solid objects, for example hailstones and sailplanes, to considerable heights. Shouldn’t have any problem at all mixing up a little CO2 :-)

    I also suppose people have actually measured the atmospheric composition at various altitudes. If it’s the same, as I suppose it is, then his theory is disproved.

  15. 165
    David B. Benson says:

    Regarding Agnes’ “science teacher” — Nobody mentioned that it is all the carbon dioxide in the atmosphere that contributes to the so-called greenhouse effect, not just the carbon dioxide in the stratosphere, as the “science teacher” claimed.

    This is correct, is it not? I’m but an amateur here, and this is pushing past the edge of my actual knowledge…

  16. 166
    Steve Reynolds says:

    Timothy Chase> But preferably someone should have spotted what the graph was suggestive of when naively interpreted – if only to prevent dishonest ideologues from taking advantage of this omission as a quick and easy means of character asassination and ad hominem attack so as to dismiss the film as vilest propaganda. Wouldn’t you agree Steve?

    I agree that the film is not the ‘vilest propaganda’. I do think the film is ‘propaganda’ in the sense that it is very one-sided, not that most of it is untrue.

  17. 167
    Timothy Chase says:

    David B. Benson (#165) wrote:

    Regarding Agnes’ “science teacher” — Nobody mentioned that it is all the carbon dioxide in the atmosphere that contributes to the so-called greenhouse effect, not just the carbon dioxide in the stratosphere, as the “science teacher” claimed.

    This is correct, is it not? I’m but an amateur here, and this is pushing past the edge of my actual knowledge…

    Well, I don’t have the numbers right off the bat, but you have to remember that water vapor is a much more effective greenhouse gas that carbon dioxide is, and in the lower atmosphere it exists in a much higher concentration. Given this, if we considered the greenhouse effect only as it takes place within the lower atmosphere, additional carbon dioxide would have very little effect at all upon the system. However, the stratosphere is much drier and the carbon dioxide molecules more distantly spaced.

    This is where the addition of carbon dioxide has its largest effect upon the system, an effect which is still smaller than that of water vapor, but not a great deal smaller. Moreover, as a doubling of the amount of carbon dioxide in the atmosphere raises the level of infrared being directed into the lower atmosphere by re-emitting roughly half of what it receives back to earth, it will heat the surface. Raising the temperature will raise rate of evaporation, amplifying the greenhouse effect due to carbon dioxide by means of increased water vapor in the troposphere. Much of this amplification will be indirect, being due to what positive feedback ensues between raised levels of water vapor and the higher temperatures which result from additional water vapor at each successive stage in the analysis.

  18. 168
    Kurt Cagle says:

    Has anyone looked at Beck’s graph if it were done correctly, ie take the break out of the horizontal axis and extend it in uniform increments to cover the 2800 year period, then fill in with the actual data? I apologize if this has been done in a previous post and I missed it. I’m not a scientist and don’t have access to the data, but just wondered what the “real” graph would look like. Obviously, if it looked like the one he shows, there would have been no reason to resort to presenting the graph as he did, so it must give quite a different looking “curve”.

  19. 169
    Alexi Tekhasski says:

    Re # 149: Ray, when you heard the word “cycle” and saw a simplified illustration for laymen, obviously you thought wrong. The Beck’s construction does not use or require periodicity. And Stefan reproduced the wrong graph from Beck’s article, just because he seems to be preoccupied by his own theory of D-O periodicity. He should better reproduce the other picture,
    http://www.readers-edition.de/wp-content/uploads/2007/05/bfuenf.jpg
    if he wanted to understand and/or refute the real argument.

    Gavin, re your response to #146: I am willing to skip your ad hom, and even admit that the word “strong” was too strong. However, the “Beck’s fakery”, as you eloquently expressed it, is no weaker than the AGW “climate CO2 sensitivity” hypothesis. Or, should I follow your lead and also call it a “fakery”? Also, the phrase you have edited out was literally copied from Ray’s post #140, word by word. Incidentally, I did not see your editing touch on his message.

    Regarding “millennial variability”, you understood Wunsch’s words (and mine) incorrectly. We didn’t assert that there is no “millennial variability”. There is a variability, just the spectral density of this variability does not differ from a rose-colored noise (relative to other time scales). To be honest, all attempts to construct an estimate of spectral density from a singe time series (that has barely a single degree of freedom) are not serious, it is a technical nonsense, it gives you about 100% uncertainty in estimations of amplitudes of individual spectral lines, especially if the time spacing between data samples is jittery and loosely defined (as I understand, you call this as “age model”). I would go ahead and even agree with you that the jitter in the alleged 1:1000 alias must be quite substantial, and is not likely to produce the relatively sharp peak. IMO, all these “peaks” are artifacts of insufficient amount of data samples relative to the time scale under discussion.

    [Response: Frankly, comparing blatant graph manipulation with the study of climate sensitivity is ridiculous. And I’m not sure who you are arguing with on the millennial variability issue. I have never thought it periodic, but there is no way it is simply rose coloured noise – do the analysis yourself on the NGRIP d18O_ice record during Stage 3 – the age model there, driven mainly by layer counting is pretty good. The problem with Wunsch’s analysis was that the exact definition of the tropical year or sidereal year just doesn’t come into it. – gavin]

  20. 170
    Timothy Chase says:

    Steve Reynolds (#162) wrote:

    See 160 (Timothy Chase). Also, think log response, not linear.

    So is that what this is about? The difference between linear and logarithmic?

    I had picked up on the fact that there was something misleading about the visual and how it might be naively interpretted from this:

    Gore shows the strong parallel relationship between the temperature and CO2 data from the ice cores, and then illustrates where the CO2 is now (384 ppm), leaving the viewer’s eye to extrapolate the temperature curve upwards in parallel with the rising CO2. Gore doesn’t actually make the mistake of drawing the temperature curve, but the implication is obvious: temperatures are going to go up a lot. But as illustrated in the figure below, simply extrapolating this correlation forward in time puts the Antarctic temperature in the near future somewhere upwards of 10 degrees Celsius warmer than present — rather at the extreme end of the vast majority of projections (as we have discussed here).

    27 Apr 2007
    The lag between temperature and CO2. (Goreâ??s got it right.)
    http://www.realclimate.org/index.php/archives/2007/04/the-lag-between-temp-and-co2/

    … but I still didn’t know what it was.

    Anyway, one can obviously argue that this is misleading – insofar as the actual mathematics isn’t explained. Then again, one could also argue that it is misleading – because he doesn’t explain that the increase in temperature will not be evenly distributed. Temperatures will rise more in the northern hemisphere than the southern, more over the higher latitudes than the tropical ones, more over land than sea. A two degree increase may easily become something much closer to ten for much of his audience. Particularly if they are used to thinking in terms of Fahrenheit than Celsius.

    *

    Trying to encapsulate the degree of climate change in terms of the rise in the average global temperature is itself very misleading – as this change in the long-term average global temperature is not for a particular place on a particular day, but for the entire planet and for all intents and purposes – permanent. As one raises this “temperature” degree by degree, the effects rise exponentially.

    Given the non-linear behavior of ice, for example, it is quite possible that business as usual will result in sea levels rising by several meters – according to one of the world’s leading climatologists. If you look at a globe, this may not seem especially significant – except in places like the Florida panhandle or perhaps India. But if you look a little more closely at say New York City or San Franciso or London, you will begin to notice something. People aren’t distributed randomly – and a lot of people will be affected. In fact, roughly half the world’s population lives within 50 miles of the coastline.

    Now of course people aren’t simply just stand still while the water rises over their heads. But people will be affected. Catastrophically. Imagine the economic cost of trying to move half of humanity – and all of the associated infrastructure? And what of the storms – which hit a more vulnerable coastline, one that is closer to the sea? And at this point, I am simply thinking in terms of sea level.

    They are projecting that we will have lost the Himalayan glaciers by the end of this century. This means water shortages for roughly a billion people. Think of what this alone means to their agriculture. According to our best projections, we will no longer be able to grow wheat in the United States. What does this imply for other crops which are currently grown in the states?

    What about the oceans – and the rising level of acidity which our emissions will result in? With the damage that this will do to the ocean’s ecological system, fish harvests will drop catastrophically in the decades to come. Think of the level of starvation that this will likely imply.

    *

    If we do not adjust our course soon, it will be much more difficult to change it later and much of what will happen will no longer be in our hands but the result of positive feedbacks which, once set in motion will take on a life of their own. In fact, it has been projected that as the result of the strong feedbacks which exist within the carbon cycle, we could reach somewhere between 730 ppm and 1020 ppm.

    At 1020 ppm, we would stand a good chance of raising the long-term average global temperature by six degrees Celsius. Near the poles where oxygen is absorbed this would be much closer to fifteen degrees. The ocean would become hypoxic, and in many of the shallower coastal areas it would become anoxic.

    That alone would be enough to kill the vast majority of life within the ocean – assuming that it wasn’t already dead as the result of the increased acidity destroying the food web. From what we know, it appears that a six degree rise in global average temperature was all it took for nature to reach the greatest mass extinction this planet has ever known.

    Think about it.

    What would be especially misleading is looking at the long-term global average temperature as if it were the same sort of thing as a particular temperature at a particular place on a particular day.

  21. 171
    Timothy Chase says:

    Steve,

    You say that Al Gore’s “An Inconvenient Truth” is “very one-sided.”

    Sounds good.

    I would quite interested in learning about the other side – since I have absolutely no idea what it is. Not on this issue. Not with what potentially hangs in the balance.

  22. 172
    ray ladbury says:

    Steve, your comment reminds me of a scene in the play “Greater Tuna” where a local activist is being interviewed on the radio because he wants to ban several books from the library.
    Interviewer: But why do you want to ban Uncle Tom’s Cabin. That’s a classic.
    Concerned Citizen: Why it only presents one side of the slavery issue.

    You have failed to document substantive inaccuracies in his presentation. Indeed, the insubstantiality of your criticisms would seem to indicate that he mostly got the science right. Just what “other side” would you suggest that Gore present. I am not a great fan of Al Gore, but you guys sure have yielded the high ground to him.

  23. 173
    Steve Reynolds says:

    Timothy Chase> I would quite interested in learning about the other side – since I have absolutely no idea what it is.

    While it can be endlessly argued whether the IPCC is too conservative (as you seem to believe) or too alarmist, the other side that most interests me is the economic one of costs vs. benefits.

    I take the moderate position (IMO) that the peer reviewed climate scientists of the IPCC are mostly right about climate effects and that the bulk of peer reviewed economists are mostly right about cost/benefit effects.

    I think those who accept the IPCC climate science view and then reject the economists have the mirror image problem of those who reject the IPCC and accept the economics.

  24. 174
    ray ladbury says:

    Re 173: Steve, now here we have some agreement. A healthy and growing economy will be essential if we are to successfully mitigate climate issues that will arise. So, would you advocate significantly increased conservation and diversification of energy sources away from fossil fuels? And would you favor a cap and trade or a carbon tax strategy to reflect the true costs of burning fossil fuels?

    BTW, I don’t think Gore’s intent was to advocate for solutions so much as to call attention to the problem. And I do think he glossed over some of the pain people are going to feel in dealing with this issue.

  25. 175
    Timothy Chase says:

    Steve Reynolds (#173) wrote:

    I take the moderate position (IMO) that the peer reviewed climate scientists of the IPCC are mostly right about climate effects and that the bulk of peer reviewed economists are mostly right about cost/benefit effects.

    I think those who accept the IPCC climate science view and then reject the economists have the mirror image problem of those who reject the IPCC and accept the economics.

    I think that anyone who believes that we can get through this simply by cinching our belts, going green and doing without is sadly mistaken. Turning our backs on modern technology and the modern global economy will not work, particularly if we have any intention of supporting eleven billion by addressing the water scarcities and food shortages which we are likely to face. Extended poverty will only mean extending the rise in population and the use of less efficient technologies. It is simple demographics.

    If we are to make it through this, we have to invest in new technologies and make them widely available. International cooperation in what are essentially the twenty-first century equivilents of the Manhattan Project. The sooner we begin the more time we will have and the less likely we will become truly desperate, lacking the means for such investments, particularly since the cost of a project will skyrocket when one is forced to complete it in less time than what is actually needed. The longer we wait, the more desparate people will become, and the more likely they will be to place their lives in the hands of some demagogue whose only concern is that of maintaining absolute power.

  26. 176
    David B. Benson says:

    Re# 167: Timothy Chase — Thank you, but by reverse induction it seems that the same effects ought to apply to half the troposphere and then half of that, etc.

  27. 177
    Jim Galasyn says:

    In 173, Steve Reynolds wrote:

    I take the moderate position (IMO) that the peer reviewed climate scientists of the IPCC are mostly right about climate effects and that the bulk of peer reviewed economists are mostly right about cost/benefit effects.

    Could you post a quick summary of what the bulk of peer reviewed economists are saying? That would be really informative. I’ve read a few things, but not enough to get a feel for the consensus.

  28. 178
    John Mashey says:

    re: #173 Steve:

    Economists’ views (of economics) *are* relevant, and there is a lot of room for argument over policy, especially for those of us who think that governments often screw up, but screw up even worse if problems get deferred until they’re desperate.

    But can you help me with the following:
    do you think:

    a) That the confidence level of long-term predictive economics is of the same order as that of current climate science?

    (It’s not probably not fair to to quote the old joke that economists have predicted 9 of the last 5 recessions, but I will anyway. I also remember the Scholes/Merton LTCM fiasco, but I know enough good economists to have some feel for how difficult and surprise-prone economics is.)

    b) That economists’ views are more or less coupled with political viewpoints as those of climate scientists?

    c) That there is anything like the consensus amongst real economists as there is amongst real climate scientists?

    For instance: to pick the most trivial metric, to what extent do they agree on the discount rate?

    I have a specific set of question-marks around:

    a) Additional dead-weight costs incurred just to stay even, which compete with other uses (like education & research & improved infrastructure) that are usually better wealth-generating investments.

    b) Impact of higher transportation costs over the next few decades, and how that affects global supply chains and the economy.

    c) The modeling of the costs of fixups, if it turns out that some costs become very large if deferred too far. (I.e., this is the usual maintenance problem, in which deferring maintenance too long can lead to very high costs.)

    d) The extent to which the long-term economic models match what we see on the ground. Private Insurance companies employ economists also, and as noted in that recent WSJ article, they are fleeing the coasts, leaving them to “lenders of last resort” or Federal/state arrangements that expect “somebody else” to pay. As a result, there is a huge, growing (but somewhat invisible) liability being accrued, which doesn’t show up in this year’s GNP.

    Anyway, can you point us at a representative sample of good economic models/analyses, i.e., more than what I read in The Economist every week, but less than 700-page reports?

  29. 179
    Susan K says:

    Last night Exxon-Mobil funded NPR’s NewsHour with Jim Lehrer had a snide little story with a meteorologist saying its how allya climate scientists are stoopid and your measurements are off coz you measure the temperatures at urban heat sink spots that …duh! …get hotter, not out in the countryside away from any activity.

    Of course they did not invite any actual climate scientist on to refute this. I assume that you know how and where to measure temperatures, right?

    Could you contact NPR NewsHour With Jim Lehrer with the facts?

  30. 180
    Steve Reynolds says:

    Jim Galasyn> Could you post a quick summary of what the bulk of peer reviewed economists are saying?

    Here is a review paper (looks at 28 published studies):

    Energy Policy 33 (2005) 2064â??2074
    The marginal damage costs of carbon dioxide emissions:an
    assessment of the uncertainties
    Richard S.J. Tol

    Abstract:
    One hundred and three estimates of the marginal damage costs of carbon dioxide emissions were gathered from 28 published studies and combined to form a probability density function. The uncertainty is strongly right-skewed.

    If all studies are combined, the mode is $2/tC, the median $14/tC, the mean $93/tC, and the 95 percentile $350/tC. Studies with a lower discount rate have higher estimates and much greater uncertainties. Similarly, studies that use equity weighing, have higher estimates and larger uncertainties. Interestingly, studies that are peer-reviewed have lower estimates and smaller uncertainties. Using standard assumptions about discounting and aggregation, the marginal damage costs of carbon dioxide emissions are unlikely to exceed $50/tC, and probably much smaller.

  31. 181
    Steve Reynolds says:

    ray ladbury> So, would you advocate significantly increased conservation and diversification of energy sources away from fossil fuels? And would you favor a cap and trade or a carbon tax strategy to reflect the true costs of burning fossil fuels?

    I favor just a carbon tax (with other taxes reduced for revenue neutrality) that is equal to estimated marginal damage costs of carbon dioxide emissions.

    That encourages conservation and shifting to non-fossil fuels automatically (no need for bureaucrats to pick winning and losing technology).

    Cap and trade seems to me designed to encourage corruption.

  32. 182
    Chuck Booth says:

    Re 175 I don’t know if the article below (excerpt only) represents the views of the “bulk” of peer-reviewed economists, but it suggests that not all economists are doom and gloom – I am curious how AGW skeptics decide which economists to listen to, and why (Do you scrutinize their arguments the way you do the climatologists’ claims about AGW?):

    Economist Sizes Up A Global Risk
    April 6, 2007
    By JOEL LANG, Hartford Courant Staff Writer

    Gary Yohe, a professor at Wesleyan University, has been in Brussels this week, helping to draft the final wording of the latest global warming report from the U.N.’s Intergovernmental Panel on Climate Change.

    Due today, the report will confirm with greater certainty than ever before that some of the most dire consequences of global warming – mass extinctions, wildfires, deadly heat waves and water shortages – are already occurring and will accelerate.
    Yohe is not a biologist or climatologist, or someone easily labeled an alarmist. He is an economist, who began working on climate change long before it was recognized as a danger. His expertise in calculating risk puts him at the center of the serious, evolving discussion over global warming. Now that science has proved beyond a reasonable doubt that greenhouse gases are causing the planet to heat up, the question is what can or should be done to stop it.

    The Supreme Court ruling this week that the gases can be classed as pollutants is expected to spur Congress to adapt national emission limits. Connecticut belongs to a New England compact that already has approved drastic cuts in emissions, as have some Western states, led by California.

    But who can guarantee the reductions will be enough to blunt the most harmful effects of global warming? And who knows whether the cost of global warming damage, assuming it can be assigned a cost, will outweigh the cost of reducing emissions? Both have been estimated in trillions of dollars.

    Yohe recognizes that science alone cannot provide the answers. Testifying before the Senate’s Energy Committee last March, Yohe said climate “contrarians” should be told:

    “You’re right! We don’t know exactly how much warming the planet will experience over the next century. We are not sure precisely how local climates will change. … We cannot guarantee that our fears about potentially dangerous climate change are justified, but you cannot be sure that they are not!”

    Among his many activities, Yohe co-edited a 2006 book, “Avoiding Dangerous Climate Change,” that contains a paper on the likelihood of one of global warming’s “doomsday” events – the collapse of the heat-carrying Atlantic waters that contain the Gulf Stream.

    Yohe himself worked on the modeling exercise with four scientists. Their results showed a 50 percent chance of collapse by 2100 if the temperature rises another 2 degrees Celsius.

    “The take-home message is this is not an experiment we want to try with the only planet we have,” Yohe said. “There is a quantifiable risk it will happen, so we should take steps to assure it won’t happen.”

    Yohe has advised thinking of global warming as an insurance risk: One pays to prepare for disaster, despite uncertainty the disaster will occur. The form of insurance he favors is a tax on carbon that begins small, but rises steadily to push long-term investment decisions toward cleaner power plants and greener buildings.

    “You have to stop adding emissions at some point. There are expensive ways to do it and cheap ways to do it,” Yohe said in one of a series of interviews.

    “You start modestly, so you don’t crash the economy. … You need a $10- or $15-a-ton tax on carbon. The critical thing is that it increases like an interest rate, forever.” He said a $10-a-ton carbon tax would add about a nickel to the price of a gallon of gas.

    Yohe is one of five Americans among 60-odd experts in Brussels working on the report due today. It is a brief summary of a 1,500 page report on which Yohe served as a lead author.

    “In our world he’s a celebrity – as close as we come to one,” said a graduate student who attended a lecture Yohe gave at the University of Connecticut the week before he left for Brussels. Yohe’s main topic was the British government’s so-called Stern Review published last fall that predicted economic catastrophe if greenhouse gases are not checked.

    The science behind the Stern Review is sound, he said, but its cost calculations are so far off-base they provide a “slow-moving target” to climate change skeptics.

    “Nobody’s clairvoyant,” Yohe said, referring again to risk policy. “The Senate can’t subpoena Mother Nature to ask her what the climate sensitivity is going to be.”…

  33. 183
    Nicolas L. says:

    re 175

    Jim,

    I don’t think there is a consensus amongst economists about the costs of climate change and mitigation, at least not like there is one amongst the climate science community on the GW. First because the real impacts of it are still to be well established by science (which is only partly done for now), secondly because its very hard in economy to convert a “natural” effect or catastrophy into a cost, thirdly because economy not only depends on data and numbers, but also on human behaviour, which is sometimes hard to handle :).
    Anyway, most economists I’ve read that studied the question aknowledge that Climate Change is gonna cost a lot to worldwide economy (in a range going from 5 to 20 % of the annual worldwide GDP by 2050), and that serious mitigation will cost about 1 to 2 or 3% of this same annual worldwide GDP (starting as soon as possible). I wouldn’t call it a consensus, but these are the most common point of views amongst the few economists that studied the question.
    The reference in this matter is the Stern report, published in 2006. It’s a few hundred pages long, but you can find a summary here:
    http://www.hm-treasury.gov.uk/independent_reviews/stern_review_economics_climate_change/sternreview_index.cfm
    The IPCC 3d group report also refers to mitigation costs:
    http://www.ipcc.ch/SPM040507.pdf

  34. 184
    Steve Reynolds says:

    Nicolas L.> The reference in this matter is the Stern report, published in 2006.

    As was quoted of Yohe in 182> “The science behind the Stern Review is sound, he said, but its cost calculations are so far off-base they provide a “slow-moving target” to climate change skeptics.”

    There is a good discussion of the (non-peer-reviewed) Stern report here:
    http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/000974the_stern_review_on_.html

  35. 185
    Steve Reynolds says:

    John Mashey 178> can you point us at a representative sample of good economic models/analyses, i.e., more than what I read in The Economist every week, but less than 700-page reports?

    I found a link to a free download of the Tol paper I mentioned earlier:
    http://ideas.repec.org/p/sgc/wpaper/19.html

    JM> a) That the confidence level of long-term predictive economics is of the same order as that of current climate science?

    My guess is that medium-term economic predictions are similar to weather/climate predictions. Predictions for economic growth for a single year ten years in the future will not be accurate, but the ten year average may be close.

    Long term economic predictions (>50 years) may be more difficult, because they depend on largely unknown factors, such as technological progress and socio-political trends.

    JM> c) That there is anything like the consensus amongst real economists as there is amongst real climate scientists? For instance: to pick the most trivial metric, to what extent do they agree on the discount rate?

    Again my guess, is they agree as well on discount rate as climate scientists do on climate sensitivity (that is mixed: the majority have some agreement, some disagree completely).

  36. 186
    ray ladbury says:

    Steve, The conclusion I would draw from that study is that economists have no clue what the marginal cost of a ton of carbon is–and that is to be expected given the uncertainties re: the consequences and response to climate change. Under such circumstances, it would seem to me that a carbon tax might be rather slow to reflect increases in our prognostication ability. Moreover, a carbon tax is every bit as susceptible to manipulation as is a cap and trade system. The advantage to a cap and trade system is that it provides businesses with a hedge against uncertainty in terms of options and derivatives as well as rewarding innovation. An example is Southwest Airlines (my favorite), which installed those little upturns on their wings and as a result has a significant fuel savings.
    Another issue you can perhaps help me with: Given that the real concern most skeptics have is about the economics of addressing climate change (and they are right to be concerned), why is it that they attack the science, which most of them do not understand and which makes Lee’s fortifications at Cold Harbor look soft by comparison. The difference seems to be that Grant learned a harsh lesson from his teacher, Lee, while the denialists seem determined to keep making the same mistakes.

  37. 187
    Rod B says:

    re 178 (John): I wasn’t asked, but a response to your questions from the peanut gallery none-the-less. I believe that: A) the confidence level of climate science is much higher than economics. B) I economists” views will on average be slightly more coupled with the politics than will climatologists’ views. C) Views of economists vary over a much wider terrain and over larger subsets of economics than that of climatologists — who mainly differ in a black-white is/is not sort of way. Reminds me of the other old saw that “only two people understand international economics, the ex chequer of England and a janitor at the national bank of France — and they don’t agree!”
    Your other muses are great, but I’ll leave them be for others. I’ve horned in enough.

  38. 188
    Jim Galasyn says:

    Thank you, Steve and everybody, for the econ cites. I’ll dive into these in the next few days.

  39. 189
    Rod B says:

    re 181: [I favor just a carbon tax (with other taxes reduced for revenue neutrality) that is equal to estimated marginal damage costs of carbon dioxide emissions.]

    I don’t see how this can be neutral. The emitters continue to emit or they don’t pay the tax. Then the carbon tax has to pay for the marginal cost of the emissions — a “new” cost. So where does the other tax reductions come from other than cutting whatever they paid for?

  40. 190
    Rod B says:

    re 182: I’m not sure if I’m impressed or comfortable with an economist and proponent of AGW science in the drivers seat of the IPCC summary report…., even if he is not quite a zealot. I’ll have to mull that over a bit.

  41. 191
    James says:

    Re #189: [So where does the other tax reductions come from other than cutting whatever they paid for?]

    Well, for a simple example, most US states have a sales tax of about 5-6%. Figure out how much revenue that brings in in an average year, and set the carbon tax rate to bring in the same amount at current use rates. Now that carbon tax is going to encourage some people to use less carbon-based energy, so next year the tax rate escalates to compensate for the decreased usage. This continues until the rate is high enough to discourage essentially all CO2 production.

    The point is that the tax rate starts out fairly low, but escalates as time goes on. This lessens any economic shock, and gives people time to adapt.

  42. 192
    Alexi Tekhasski says:

    In #170, Timothy Chase is concerned about “the rising level of acidity” in oceans. I would suggest not to use alarming and incorrect terminology. Oceans are substantially alcaline, so no acidity is rising, technically speaking. More, the alkalinity seems to be even _rising_ in the last 20 years, see:

    http://www.bbsr.edu/Labs/co2lab/research/IntDecVar_OCC.html#fig1

    Cheers,
    – Alexi

    [Response: Funny! (and an object lesson in not just googling on terms you are not familiar with to make a debating point). The graph highlighted clearly shows pH decreasing (ie. the water becoming more acidic). It also shows “Total Alkalinity” increasing. Contradictory? No. Read all about it: Total Alkalinity. Quote: “Alkalinity is sometimes incorrectly used interchangeably with basicity”. Indeed. – gavin]

  43. 193
    Chuck Booth says:

    Re 190 Concern about economist Yohe writing IPCC Report

    Rod,
    If your skepticism about AGW is rooted in your concern about the impact on the economy if AGW is real (and you have suggested as much in several of your RC posts), I can imagine this might be rather disconcerting.

    However, I don’t think you need to worry too much. It is my impression that Yohe was not really “in the driver’s seat” of the report – rather, he was one of many economists who authored a portion of the report. That economists have contributed to the IPCC reports shouldn’t surprise you – you have read those reports, haven’t you?

  44. 194
    David B. Benson says:

    I encourage the use of the term net fossil carbon tax. The use of bio-mass for fuels is presumably carbon neutral and putting carbon into the ground, for example, via biochar, is carbon negative.

  45. 195
    Steve Reynolds says:

    ray ladbury 186> The conclusion I would draw from that study is that economists have no clue what the marginal cost of a ton of carbon is–and that is to be expected …

    If the IPCC did not exist to enforce a consensus, would it appear that climate scientists had a clue about climate sensitivity?

    RL> a carbon tax is every bit as susceptible to manipulation as is a cap and trade system.

    I believe economists disagree. It is much harder for politicians to manipulate a tax, since the expectation is that everyone emitting carbon will pay it.

    See this link for carbon trading problems:
    http://environment.guardian.co.uk/climatechange/story/0,,2104395,00.html

    RL> The advantage to a cap and trade system is that it provides businesses with a hedge against uncertainty in terms of options and derivatives as well as rewarding innovation. An example is Southwest Airlines (my favorite), which installed those little upturns on their wings and as a result has a significant fuel savings.

    A tax should at least provide the same incentives, and with less uncertainty (look at the European example of volatile trading prices).

    RL> Another issue you can perhaps help me with: Given that the real concern most skeptics have is about the economics of addressing climate change (and they are right to be concerned), why is it that they attack the science…

    Not being a skeptic of AGW, I can not answer as one, but for myself, better transparency would help reduce doubts. See James Annan’s experience:
    http://julesandjames.blogspot.com/2007/05/no-comments.html

  46. 196
    Timothy Chase says:

    David B. Benson (#193) wrote:

    I encourage the use of the term net fossil carbon tax. The use of bio-mass for fuels is presumably carbon neutral and putting carbon into the ground, for example, via biochar, is carbon negative.

    Interesting point about bio-mass fuels being carbon neutral.

    At the same time, it reminds me of the greenhouse effect itself where the energy is conserved since that which enters the system ultimately leaves the system – but the amount which is in the system at any given time increases. With the higher turnover rate, it would seem that while in a sense bio-mass fuels are carbon neutral, the turnover would be greater, resulting in a net increase in the amount of carbon which is in the atmosphere at any given time.

    But I may be wrong.

    In any case, as you yourself have pointed out, the liquid fuels from the production of agrichar/biochar are carbon neutral, the production of agrichar itself results in no carbon emissions, the sequestration when agrichar is put into the soil is on the order of centuries. Given the lower rate of turnover, we would be reducing the amount of carbon in the atmosphere at any given time.

    And as you have pointed out, the boost to agriculture which results from soil enrichment is quite substantial. It would potentially eliminate our dependence on phosphate fertilizers, reducing phosphate runoff and consequently the algae blooms which result in anoxic dead zones off the the coasts.

    This last consequence is something which Jim Galasyn and myself would be particularly interested in.

    There are a good many reasons for advocating the use of agrichar.

  47. 197
    David B. Benson says:

    Re #196: Timothy Chase — I don’t follow the turnover argument. As long as one grows bio-mass for fuels as fast as the resulting biofuels are burned, it seems to me to be carbon neutral.

    By all means advocate the use of agrichar!

    One of the articles made the claim (if I recall corrrectly) that, assuming no agricultural value, agrichar for fossil carbon offset puposes requires a tax on carbon of US $37 per ton. I’ll push for that figure, starting right away…

  48. 198
    John Mashey says:

    The Tol paper (2003 version, which has slightly different numbers) was interesting.

    There is a wide variation in the assumptions and cases being considered, and I’m still not sure yet how much of this is like company budget processes: there’s top-down, and bottom-up, and sometimes they are wildly different. Tol writes:

    “Overall, the current generation of aggregate estimates may understate the true cost of climate change because they tend to ignore extreme weather events; underestimate the compounding effect of multiple stresses; and ignore the costs of transition and learning. However, studies may also have overlooked positive impacts of climate change and not adequately accounted for how development could reduce impacts of climate change.”

    a) Heavily-skewed distributions are always tricky, and it is really difficult to deal with rare events.

    It is worth reading Nassim Nicholas Taleb’s books, or keep Sam Savage’s short “The Flaw of Averages” in mind:
    http://www.stanford.edu/~savage/flaw/
    Sam teaches a great 1-day course on this at Stanford.

    (This is *not* a disguised plea for the Precautionary Principle, just a note that if rare events are mostly negative and big, you have to think hard about their handling. This is all somewhat akin to the difference in computer performance between average response time and worst-case response time, and the different treatments therein between your desktop PC (where worst-case doesn’t really matter too much) and in real-time control systems for fighter planes (where it does).)

    b) Tol analyzes the data in various different ways, which is good. In some cases, if a study cites a standard deviation, he assumes a normal distribution, which is probably as good an assumption as he can make, although if the underlying studies were also right-skewed, a lognormal might fit better.

    c) I’ll have to go look some more, but I’m struck by several things in Table 1, which shows 4 studies estimating regional impacts of climate change (+ being benefits, – being costs), for (mostly) 2.5C rise, but on current economy:

    2.5C: Pearce et al expect a -1.5% to -2% hit overall, with a -1.5% hit in N. America, and a -1.0 to -1.5 hit in USA. I think that means that they think it hurts Mexico more (likely), since it must hurt Canada less or more likely help it.

    2.5C: Nordhaus/Boyer are fairly similar, with -1.5% overall.

    2.5C: Mendelsohn et al (but for future economy):
    +11.1% for Russia (yes, good for Russia)
    +0.3% for USA ?
    -2.0% for India
    +1.8% for China ?
    +0.1% overall

    1.0C: Toll
    +3.4% for N. America ?
    +1.1% Middle East ??
    +2.3% overall

    Some of these seem counterintuitive, which is why it’s nice to get bottom-up analyses, often easier to evaluate than “costs for the world.”

    It’s not obvious why a 1C rise adds 1.1% to the MiddleEast economy.

    It is very counterintuitive to think that a 1.0C rise is an overall 3.4% benefit to the US economy, but that may be bias from living in California, which has many identifiable costs, and few offsetting benefits.

    For example, some of these are detailed in:
    http://www.climatechange.ca.gov/research/index.html, with some specific bottom-ups:
    http://www.climatechange.ca.gov/research/economic.html
    although these are primarily about water, and don’t include the coastal/Bay Area sea level issues, insects, and ski resorts, and heat-vs-air-conditioning balance. At least on the West Coast, development is is disallowed on much of the seashore, and in parts of the SF Bay Area, wetlands are a buffer for that first 1-2′ of rise, but there will have to be some serious dike-building.

    In the USA, the balance clearly varies wildly on a state-by-state basis, from pretty negative (FL, LA, TX, NM, AZ, CA) to positive (Upper MidWest), so it will be useful to look at these studies in more detail to see where the numbers come from, and especially to understand the treatment of expensive, somewhat-unpredictable events like hurricanes, floods, and fires.

    d) In Figure 2, the composite P.D.F. of marginal costs of carbon dioxide shows a reasonable fraction from -$25 to $0 / tonne of carbon. Thus, in some studies, it almost seems like we should be subsidizing CO2, rather than taxing it. Is that what that chart means?

    Wikipedia has useful thing to say on discount rate and climate change:
    http://en.wikipedia.org/wiki/Discount_rate
    http://en.wikipedia.org/wiki/Economics_of_global_warming

  49. 199
    John Mashey says:

    The Tol paper (2003 version, which has slightly different numbers) was interesting.

    There is a wide variation in the assumptions and cases being considered, and I’m still not sure yet how much of this is like company budget processes: there’s top-down, and bottom-up, and sometimes they are wildly different. Tol writes:

    “Overall, the current generation of aggregate estimates may understate the true cost of climate change because they tend to ignore extreme weather events; underestimate the compounding effect of multiple stresses; and ignore the costs of transition and learning. However, studies may also have overlooked positive impacts of climate change and not adequately accounted for how development could reduce impacts of climate change.”

    a) Heavily-skewed distributions are always tricky, and it is really difficult to deal with rare events.

    It is worth reading Nassim Nicholas Taleb’s books, or keep Sam Savage’s short “The Flaw of Averages” in mind:
    http://www.stanford.edu/~savage/flaw/
    Sam teaches a great 1-day course on this at Stanford.

    (This is *not* a disguised plea for the Precautionary Principle, just a note that if rare events are mostly negative and big, you have to think hard about their handling. This is all somewhat akin to the difference in computer performance between average response time and worst-case response time, and the different treatments therein between your desktop PC (where worst-case doesn’t really matter too much) and in real-time control systems for fighter planes (where it does).)

    b) Tol analyzes the data in various different ways, which is good. In some cases, if a study cites a standard deviation, he assumes a normal distribution, which is probably as good an assumption as he can make, although if the underlying studies were also right-skewed, a lognormal might fit better.

    c) I’ll have to go look some more, but I’m struck by several things in Table 1, which shows 4 studies estimating regional impacts of climate change (+ being benefits, – being costs), for (mostly) 2.5C rise, but on current economy:

    2.5C: Pearce et al expect a -1.5% to -2% hit overall, with a -1.5% hit in N. America, and a -1.0 to -1.5 hit in USA. I think that means that they think it hurts Mexico more (likely), since it must hurt Canada less or more likely help it.

    2.5C: Nordhaus/Boyer are fairly similar, with -1.5% overall.

    2.5C: Mendelsohn et al (but for future economy):
    +11.1% for Russia (yes, good for Russia)
    +0.3% for USA ?
    -2.0% for India
    +1.8% for China ?
    +0.1% overall

    1.0C: Toll
    +3.4% for N. America ?
    +1.1% Middle East ??
    +2.3% overall

    Some of these seem counterintuitive, which is why it’s nice to get bottom-up analyses, often easier to evaluate than “costs for the world.”

    It’s not obvious why a 1C rise adds 1.1% to the MiddleEast economy.

    It is very counterintuitive to think that a 1.0C rise is an overall 3.4% benefit to the US economy, but that may be bias from living in California, which has many identifiable costs, and few offsetting benefits.

    For example, some of these are detailed in:
    http://www.climatechange.ca.gov/research/index.html, with some specific bottom-ups:
    http://www.climatechange.ca.gov/research/economic.html
    although these are primarily about water, and don’t include the coastal/Bay Area sea level issues, insects, and ski resorts, and heat-vs-air-conditioning balance. At least on the West Coast, development is is disallowed on much of the seashore, and in parts of the SF Bay Area, wetlands are a buffer for that first 1-2′ of rise, but there will have to be some serious dike-building.

    In the USA, the balance clearly varies wildly on a state-by-state basis, from pretty negative (FL, LA, TX, NM, AZ, CA) to positive (Upper MidWest), so it will be useful to look at these studies in more detail to see where the numbers come from, and especially to understand the treatment of expensive, somewhat-unpredictable events like hurricanes, floods, and fires.

    d) In Figure 2, the composite P.D.F. of marginal costs of carbon dioxide shows a reasonable fraction from -$25 to $0 / tonne of carbon. Thus, in some studies, it almost seems like we should be subsidizing CO2, rather than taxing it. Is that what that chart means?

    Wikipedia has useful thing to say on discount rate and climate change:
    http://en.wikipedia.org/wiki/Discount_rate
    http://en.wikipedia.org/wiki/Economics_of_global_warming

  50. 200
    ray ladbury says:

    Steve, I in no way was attempting to tar you with the same brush the denialists willingly slop on. However, it would seem that you are in some contact with said elements.
    First, it is a misnomer to state that the IPCC “enforces” consensus. Indeed, wrt some issues (e.g. climate change increasing tropical storm intensity) I think they have slightly outrun consensus, while on others (e.g. melting of ice, consequences of climate change) they lag behind. On the whole, they REFLECT consensus pretty well, though.

    WRT a carbon tax vs. carbon trading, the problem I see with a tax is that it would have to be coordinated globally, or it would become a race to the bottom. There is certainly more prospect for corruption and subversion of such a taxation regime. I have more faith in markets than I do in governments, but then somebody must guard the guards.

    My question stems from my recent experience in the belly of the beast–to wit, the comments on the Blog related to the New Scientist

    https://www.blogger.com/comment.g?blogID=37849569&postID=6984028916615849498

    Oh my God! The nutjobs are out in force. By far, the funniest reference cited is

    http://www.gsaaj.org/articles/TempPaperv1n22007.pdf

    This is a post byOther than that, it’s the usual suspects.

    John Mashey, if you want to add to your psychological profiles, I suggest a visit. In fact, there has been only one other poster who knows any science posting there all week. There is a risk that the entire blog may collapse under the weight of the ignorance of the posters.


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