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What do climate scientists think?

Filed under: — gavin @ 24 June 2010 - (Español)

by Gavin and Eric.

… and why does it matter?

There is a lot of discussion this week about a new paper in PNAS (Anderegg et al, 2010) that tries to assess the credibility of scientists who have made public declarations about policy directions. This come from a long tradition of papers (and drafts) where people have tried to assess the state of the ‘scientific consensus’ (Oreskes, Brown et al, Bray and von Storch, Doran and Zimmerman etc.). What has bedevilled all these attempts is that since it is very difficult to get scientists to respond to direct questions (response rates for surveys are pitiful), proxy data of some sort or another are often used that may or may not be useful for the specifics of the ‘consensus’ being tested (which itself is often not clearly defined). Is the test based on agreeing with every word in the IPCC report? Or just the basic science elements? Does it mean adhering to a specific policy option? Or merely stating that ‘something’ should be done about emissions? Related issues arise from mis-specified or ambiguous survey questions, and from the obvious fact that opinions about climate in general are quite varied and sometimes can’t easily be placed in neatly labelled boxes.

Given these methodological issues (and there are others), why do people bother?

The answer lies squarely in the nature of the public ‘debate’ on climate. For decades, one of the main tools in the arsenal of those seeking to prevent actions to reduce emissions has been to declare the that the science is too uncertain to justify anything. To that end, folks like Fred Singer, Art Robinson, the Cato Institute and the ‘Friends’ of Science have periodically organised letters and petitions to indicate (or imply) that ‘very important scientists’ disagree with Kyoto, or the Earth Summit or Copenhagen or the IPCC etc. These are clearly attempts at ‘arguments from authority’, and like most such attempts, are fallacious and, indeed, misleading.

They are misleading because as anyone with any familiarity with the field knows, the basic consensus is almost universally accepted. That is, the planet is warming, that human activities are contributing to the greenhouse gases in the atmosphere (chiefly, but not exclusively CO2), that these changes are playing a big role in the current warming, and thus, further increases in the levels of GHGs in the atmosphere are very likely to cause further warming which could have serious impacts. You can go to any standard meeting or workshop, browse the abstracts, look at any assessment, ask any of the National Academies etc. and receive the same answer. There are certainly disputes about more detailed or specific issues (as there is in any scientific field), and lots of research continues to improve our quantitative understanding of the system, but the basic issues (as outlined above) are very widely (though not universally) accepted.

It is in response to these attempts to portray the scientific community as fractured and in disagreement, that many people have tried to find quantitative ways to assess the degree of consensus among scientists on the science and, as with this new paper, the degree of credibility and expertise among the signers of various letters advocating policies.

It is completely legitimate to examine the credentials of people making public statements (on any side of any issue) – especially if they make a claim to scientific expertise. It does make a difference if medical advice is being given by a quack or the Surgeon General. The database that Jim Prall has assembled allows anyone to look this expertise up – and since any new source of information is useful, we think this can be generally supported. Prall’s database has a number of issues of course, most of them minor but some which might be considered more problematic: it relies on citation statistics, which have well-known problems (though mostly across fields rather than within them), it uses Google Scholar rather than the standard (ISI) citation index, and there are almost certainly some confusions between people with similar names. Different methodologies could be tried – ranking via h-index perhaps – but the as long as small differences are not blown out of proportion, the rankings he comes up with appear reasonable.

So it is now possible to estimate an expertise level associated with any of the various lists and letters that are out there. Note that it is worth distinguishing between letters that have been voluntarily signed and lists that have been gathered with nothing but political point scoring in mind (the Inhofe/Morano list was egregious in its cherry picking of quotes in order to build up its numbers and can’t be relied on as an accurate reflection of peoples opinions in any way, and similarly contributing to RealClimate is not a statement about policy preferences!). Additionally, it isn’t always clear that every signatory of each letter really believes every point in the statement. For instance, does Lindzen really believe that attribution is impossible unless current changes exceed all known natural variations (implying that nothing could be said unless we got colder than Snowball Earth or warmer than the Cretaceous or sea level rose more than 120 meters….)? We doubt it. But as tests of political preferences, these letters are probably valid indicators.

So, do the climate scientists who have publicly declared that they are ‘convinced of the evidence’ that emission policies are required have more credentials and expertise than the signers of statements declaring the opposite? Yes. That doesn’t demonstrate who’s policy prescription is correct of course, and it remains a viable (if somewhat uncommon) position to acknowledge that despite most climate scientists agreeing that there is a problem, one still might not want to do anything about emissions. Does making a list of signers of public statements, or authors of the IPCC reports, constitute a ‘delegitimization’ of their views? Not in the slightest. If someone’s views are widely discounted, it is most likely because of what they have said, not who they sign letters with.

However, any attempt to use political opinions (as opposed to scientific merit) to affect funding, influence academic hiring, launch investigations, or personally harass scientists has no place in a free society – from whichever direction that comes. In this context, we note that once the categorization goes beyond a self-declared policy position, one is on very thin ice because the danger of ‘guilt by association’. For instance, one of us (Eric) feels more strongly that some of Prall’s classifications in his dataset cross a line (for more on Eric’s view, see his comments at Dotearth).

But will this paper add much to the ‘there [is/is not] a consensus’ argument? Doubtful. People are just too fond of it.

But there really is.


427 Responses to “What do climate scientists think?”

  1. 251

    250

    “I noted that papers that print articles that are wrong are demanded to apologize as well as correct. Why? Do scientists apologize when they get it wrong?”

    Scientists or Journalists not recognizing their mistakes are handicapped by their pride, eventually their writings
    become without merit or substance while practicing incompetence. Anyone finding error in their judgement
    has a better grasp of science.

  2. 252
    SecularAnimist says:

    BPL wrote: “So mark me down for breaking Godwin’s Law.”

    Actually, your “Ein Reich, ein Volk, Ayn Rand!” comment would be an empirical verification of Godwin’s Law, not a violation of it.

  3. 253
    Didactylos says:

    HotRod: your argument boils down to “Doing X is stupid, therefore nobody will do X, therefore nobody can be doing X”. There are many deniers who routinely make the most outrageous policy recommendations (including doing nothing), just as AIDS deniers have advocated (and implemented) dangerous and nonsensical policies based on their claim that HIV is not related to AIDS.

    So, it’s not a false dichotomy as you claim – instead, you have overlooked some very well-known contradictions that undermine your whole theory.

  4. 254
    Pete Dunkelberg says:

    Gavin @ 211 “Argument for argument sake is pointless.”

    If everyone took that to heart think how few comments there would be. ;)

    Giles – use your self-stated scientific prowess to answer your own question about significance of the temperature rise during the period 1880 – 2010. Note that the temperature hump during WWII is an artifact.
    Giles – did you forget attribution again? This isn’t just statistics.

  5. 255
    wili says:

    John at 248.

    Thanks for the link. I am aware of that study. It was the subject of a thread here. The question I was trying to pose was not when would methane start to be released–that is already happening as the article pointed out.

    The question is when will it start erupting in volumes that dramatically affect the climate.

    Some here have suggested that this could essentially never happen–that methane will only trickle out at such a low rate that it will now be a significant game changes, since it decays into CO2 and water in a few years.

    But as we move toward an ice-free Arctic, lots of shallow water, especially the continental shelf north of Siberia, will be not only much warmer, but more turbulent (sea ice calms waves–lack of it allows larger waves).

    I would like, for my own grim reasons, to be able to see this thing coming, if it’s coming, in something like real time. But most of the methane sensing data is only update every few weeks or months, depending on the location.

    Does the public have access to any of the satellite data?

  6. 256
    Gilles says:

    “Giles – use your self-stated scientific prowess to answer your own question about significance of the temperature rise during the period 1880 – 2010. Note that the temperature hump during WWII is an artifact.
    Giles – did you forget attribution again? This isn’t just statistics.”

    I agree. This isn’t just statistics, obviously. That’s the issue : were it just statistics, things would be much simpler.

  7. 257
    Leonard Evens says:

    Re 245 and claim that Hansen has been found guilty of fudging data. I tried using google on “Hansen Fudging”. I found several references to Hansen’s complaints about the Bush administration’s fudging data, but I also found thenewliberty.com/?p=612 which quotes Christopher Booker. His main complaint seems to be that it seems to have been cold in Europe, but there doesn’t seem to be anything else. Booker is known, among other things, for questioning whether asbestos causes cancer.

  8. 258
    Patrick 027 says:

    Re 243 HotRod (re Eric) -

    First, to second 254 Didactylos, while knowledge of only some of the relevant facts is not enough to devise good policy, ignorance of some of the relevant facts can be an impediment to devising good policy. Actually, those two statements are quite similar. Knowledge of climate and ecology is important for the same reason that it is not sufficient by itself.

    I just don’t think climate scientists should opine on the policy choices they believe are needed, because they look stupid, as I would if I opined on climate feedback.

    They could. But what if they don’t look stupid? You have to know what they’re gonna say before you can say it will be stupid.

    When a combustion expert, geologist, meteorologist, economist, politician, pundit, or science-fiction author says something about AGW, it may look stupid. But that’s because of what they might say. Another combustion expert, geologist, meteorologist, economist, politician, pundit, or science-fiction author might have either enough knowledge of climate or enough awareness of their own limitations to be able to say something quite smart about AGW. For that matter, when they say something stupid about AGW, it isn’t necessarily about the climate physics – it could be about geology or economics or government.

    Several months ago I posted a series of rather long comments in which I outlined what I think to be a good policy regarding AGW. I breezed through some of it again in a comment above (somewhere around or before 150, I think). (Note what I did not do in those comments: I did not estimate any numerical values for an emissions tax. I don’t have the knowledge to do that, even in a back-of-the-envelope sort of way. What I did was a lay out a general framework based on the concept of an efficient market, plus an awareness of realistic inefficiency. Which, just to be clear, I am not claiming to be original – obviously it isn’t, although there might be an original part or two somewhere in there. I’ve been exposed to ideas and I’ve thought about them and the policy I described is a result of that.) (And I’m not even an actual scientist (might be at some point in the future, though) or economist.)

  9. 259
    Septic Matthew says:

    150, former sceptic: Anderegg et al. was peer reviewed in the proper manner.

    I stand corrected. It was reviewed by a social scientist?

  10. 260
    John E. Pearson says:

    Burton Richter on climate and energy:

    A Nobelist’s Energy Pitch for Obama

    http://dotearth.blogs.nytimes.com/2010/06/28/a-nobelists-energy-pitch-for-obama/?hp

  11. 261
    Geoff Wexler says:

    Re My #244:

    I’ve just seen Panorama.

    Comment: The final version was rather worse than I expected because it was framed by references to the emails stolen from the CRU. It really appears that these editors think that is the main news item …
    but they haven’t even followed that story well enough to tell it properly. Several allegations were repeated but not countered in the programme.

    As for the science, that was based on the very brief interviews I linked in #244.

    If you have a good enough computer you can probably find the final thing on the web.

  12. 262
    David B. Benson says:

    Lynn Vincentnathan (245) — Consdier passing along
    David Greenwood’s comment at Climatesight
    http://climatesight.org/the-credibility-spectrum/#comment-2320
    which is short and clar.

  13. 263
    Dan Sinnett says:

    Might be a random interjection, but I’m just wondering if anyone saw this article in ARS Technica:

    http://arstechnica.com/science/news/2010/06/climate-friction-as-past-papers-meet-their-critics.ars

    It discusses the PNAS paper, censorship issues, and the like. Nice to know the geek/hacker culture is on-board with AGW/ACC.

    Why the change in terminology anyway?

  14. 264
    Patrick 027 says:

    Dan Sinnet: AGW-ACC terminology?

    I’ve heard that those who wanted to anesthetize the public to the issue prefered ACC (or just CC), which doesn’t automatically (to the lesser-informed) conjur up images of melting ice caps and rising sea levels and heat waves, and could refer to cooling or warming or any persistent shift in weather patterns. However, changes to climate that come with AGW or would tend to come with GW in general are more than a global average surface temperature increase, and ACC could be seen as a more all-encompassing term. ACC would also include any ‘special’ regional effects of aerosols; aside from that, though, I think either term works.

  15. 265

    I’m guessing that the poster to Lynn’s blog was just regurgitating inaccurately–a bit of D’Aleo, a bit of Climategate, whirl in a blender and serve hot.

    I’m afraid a lot of these guys (based on those whom I’ve encountered) aren’t really big on detail anyway.

    On another topic, yes, the melt season so far has been quite spectacular. It’s amazing how deep in denial the WUWT crew are; Steve Goddard has convinced himself that nothing odd is going on.

    (How? selective data, of course–right now, he’s pinning his hopes on the UniBremen Arctic temperature graph, which shows slight cooling for the area north of 80 degrees*, and on the U.S. Navy PIPS 2 ice forecast. Ironically, both of these sources depend upon computer modeling, but they are currently providing a result that he approves of.)

    *The great majority of the sea ice lies below this latitude–Hudson Bay, for instance, which was referred to above, extends down to the 50′s.

  16. 266
    Jim Eager says:

    Kevin, the ice in Hudson Bay is just about gone, and it’s not even the end of June.

  17. 267
    Frank Giger says:

    @ Patrick in 248:

    “I can understand the concern about scientist-activists, but it should not be so hard to accept that people who actually know things may be moved to publically argue against confusion and misunderstanding.”

    It is one thing to stick up for the science – I approve! However, one must remember that many a researcher grabbed an idea and refused to let go even when the evidence went against them largely because they had defined themself as a scientist as much by their activism as their research.

    It is quite another for a scientist to begin advocating for a specific political solution, however.

    One can agree completely with the science and disagree with the current political solutions being offered. Unfortunately its actually rare when people are involved. You’ll read accusations that I’m a “denier” of the science within these comment sections for that reason – or accused of wanting to “do nothing” in the face of climate change.

    Neither is true – but it’s par for the course within political disagreements to lump people into boxes.

    The science is apolitical – but that stops right about the nanosecond after someone says “so what do we do about it?”

    :)

  18. 268

    Trust me, Jim, I’ve noticed! This is one of the remarkable things going on.

    Another is the melting through the Canadian Archipelago. It’s leading to speculations (some of them mine) about when one or more of the Northwest Passage routes may open this year.

    Weather events always influence the melt season in unexpected ways, it seems. But even if melt is more or less “normal” (whatever that means today) this will have been a rather spectacular season. And I really doubt that it is going to be merely normal.

    For those interested, Neven has a new–well, it’s still pretty new–blog on this topic here:

    http://neven1.typepad.com/

    Unassuming name, I know, but there’s been rather a lot of good discussion & sharing of sources.

  19. 269
    Mal Adapted says:

    http://arstechnica.com/science/news/2010/06/climate-friction-as-past-papers-meet-their-critics.ars

    It discusses the PNAS paper, censorship issues, and the like. Nice to know the geek/hacker culture is on-board with AGW/ACC.

    Would that it were so. That was a reasonable article, as are most of the comments. OTOH, read anything on the subject by Eric Raymond, or Andrew Orlowski 8^(.

  20. 270
    Edward Greisch says:

    249 Scott A Mandia: Regional nuclear wars will be part of the breakdown. For example, India, Pakistan and China will fight over water. I expect lots of nuclear wars.
    Have you ever thought about a run on grocery stores? Runs on banks are history. Runs on grocery stores will be new. But it won’t stop there. If there are no groceries, nobody goes to work, so civilization collapses. Everybody wanders off in search of food. Now, they can wander over the whole Earth, eating everything to extinction. Once that is done, they will turn on each other. NO place on Earth will be safe. [Can I move to Mars now, please?] The higher northern latitudes will be no sanctuary because people can travel too well. People will be a lot worse than locusts could ever be. Once all of the food is eaten to extinction, it is all over.

    There are several more kill mechanisms in Mother Nature’s arsenal. She will use them.

    [Response: Can we please move on from apocalyptic doomsday scenarios? These conversations never go anywhere and everyone is very clear about how you feel on this issue. - gavin]

  21. 271

    266 Kevin, Goddard statements? Quite off the mark, surface temperatures are mostly average because there is still some ice reflecting sunlight, but sunlight is very intense due to low cloud extent and high sun elevations, and does not show immediately above the ice, but further up. I calculate closer density weighted temperatures between Arctic and temperate upper air stations , while there may be 25 – 30 C difference between temperate and Arctic surface observations, the DWT temperatures are often less than 10 degrees apart.

    http://www.esrl.noaa.gov/psd/map/images/fnl/sfctmpmer_30b.fnl.html

    Note last 30 days temperature anomaly over Hudson Bay, and it shows no anomaly, yet over the same last 30 days all ice about vanished. What he misses to consider is the state of the ice as built over the entire winter.
    Also other major things like cloud coverage sst’s, crucial in analyzing great melts. I can’t see him practicing good melt estimates but at least he makes a projection, good for him, hope he corrects his mistakes (thereafter) when he will find out the extent of the melt of 2010…

  22. 272
    Hank Roberts says:

    The US industries that have been involved in changing the climate likely can greatly reduce their defensive investment in advocacy science, assuming this new precedent (limiting costs to remedial gestures, and ruling out big financial penalties), would apply to them.
    http://www.dailyfinance.com/story/company-news/tobacco-industry-supreme-court-280-billion-dollar/19534044/

  23. 273
    Timothy Chase says:

    Hank Roberts wrote in 272:

    The US industries that have been involved in changing the climate likely can greatly reduce their defensive investment in advocacy science, assuming this new precedent (limiting costs to remedial gestures, and ruling out big financial penalties), would apply to them.
    http://www.dailyfinance.com/story/company-news/tobacco-industry-supreme-court-280-billion-dollar/19534044/

    What can I say? It is the same Supreme Court that decided that Exxon and other corporate “artificial persons” are a disadvantaged class whose financial contributions to political candidates constitutes a form of “Free Speech” that deserves constitutional protection.

  24. 274
    ScaredAmoeba says:

    [edit - OT]

  25. 275
    pete best says:

    Its interesting to know that where John Cristy was an outright denier (so to speak) for many years he now accepts ACC/AGW but only attributes 25% of the temperature rises to humans and the rest from natural variability and/or other factors (probably the sun) for which he states that upto 30% of climte scientists are with him in being skeptical of CC human causes

    http://www.telegraph.co.uk/earth/environment/climatechange/7849441/Michael-Mann-says-hockey-stick-should-not-have-become-climate-change-icon.html

    Ah the battle continues only in a new guise now with new arguments based on the science rather than outright denial.

  26. 276

    HotRod 243: you say ‘I sure as heck would not want to have anyone (whether they are a ‘policy expert’ or not) dictating health policy predicated on the grounds that HIV does not cause AIDS’ – but surely health policy would be not based on that simplistic black/white question

    BPL: Surprise! Policy was made on EXACTLY THAT BASIS in the Republic of South Africa–and millions of people died who might have been saved.

    Don’t kid yourself. Bad science can inform policy. [edit - OT]

  27. 277

    Patrick 259 — Sweden started out with $100 per ton of CO2 ($27 per ton of C) and has now raised it to $150, with significant effects on Swedish CO2 output. I think Norway is following a similar policy. I was surprised to find out that several countries, mostly in Europe, have already implemented carbon taxes, with good results–except in Finland, where they vitiated it by giving exemptions to the most carbon-intensive industries!

  28. 278
    ChrisD says:

    Patrick #265:

    I’ve heard that those who wanted to anesthetize the public to the issue prefered ACC (or just CC)

    You don’t have to rely on rumor; in this case there actually is a smoking gun. Read page 142 of this document (the rest of it is interesting, too):

    http://www.ewg.org/files/LuntzResearch_environment.pdf

    This is a report written by Republican pollster/media consultant Frank Luntz. It was distributed to the Bush White House and senior Republicans in Congress. Someone (can’t remember who) did a LexisNexis search and found that Bush consistently said “global warming” before the date of this report and “climate change” after it.

    Now, having said that, there’s nothing wrong with “climate change.” Global warming is one aspect of climate change (and not the worst one, in my view). And we should also remember what the “CC” in “IPCC” stands for, and that IPCC was organized in 1987.

    But what is not true is the meme that the “enviros” changed the terminology in order to cover their bases when global warming failed to appear on schedule. This is patently, obviously, and demonstrably false.

  29. 279
    Neil Bates says:

    It seems to me, the major “legitimate” dispute is over the magnitude of the forcing factor. That is, how much warming effect is likely compared to some simple baseline of just taking direct absorption by changing levels of CO2. I even got Lubos Motl to admit CO2 was a GH gas, he just said the forcing factor was around one instead of three or so as the consensus states. So if you can split utter deniers from FF wranglers, there can be a better debate. In any case, as Tom Friedman points out: the exact risk factor for temperature change doesn’t matter a lot, we’re smart to ward it off and achieve more energy independence anyway.

    (BTW, the skeptics like to game the Beer’s Law thing – “existing CO2 already absorbs all the IR from the ground” – forgetting that absorbed heat has to be re-emitted, and more CO2 shifts up the equilibrium temperature. They also front up confusion over how much warmer we are v. an airless world, against the real question of how much temperature increase we can expect over that. And so on.

    BTW, I think dew points are getting even worse that temperatures per se. I want to see charts of global DPs over time. Around here in SE VA, we’re getting lower 70s in June – that is almost unprecedented. And, it used to snow more often.

  30. 280
    Gilles says:

    BPL, 100 $ per ton of CO2 is not 27$ per ton of C but rather 300 $, since 1 tC = 3t CO2 approximately. But it represents “only” 50 $/bl.

    Note that results were not so good in Netherlands and in Norway, and the CO2 emission of France leveled off since 1990 too, although no extra carbon tax was imposed.

    But there is a strange contradiction in the supposed effect of a tax. Everybody agrees that emitting more than 1000 GtC can be possible only if we extract massively unconventional resources. And everybody agrees that these unconventional resources can become economically profitable only if the prices increases substantially, much more than 100 $ per ton of C. So the tax is supposed to be efficient to reduce the consumption , but the bigger increase of the price of fossil fuels is supposed to do nothing at all, since it would accompany a huge increase of consumption.?

  31. 281
    Ray Ladbury says:

    Neil Bates and Pete Best,
    I am not sure how large your respective victories are. Both Christy and Motl continue to argue in a manner utterly unconstrained by evidence. I do not see how either man produces their “estimates” unless they are pulling them out of some alternative orifice. Motl’s long-time dalliance with string theory (I don’t think he’s produced anything useful) could explain his lack of respect for evidence, but Christy ought to know better.

  32. 282
    SecularAnimist says:

    gavin wrote: “Can we please move on from apocalyptic doomsday scenarios?”

    That’s a really poignantly ironic comment, when you think about it.

    Sometimes when I look at how AGW is proceeding right before our very eyes, I feel like I am asking Nature that very question.

    And Nature replies, “Uh, no, not really.”

  33. 283
    ccpo says:

    “Giles – use your self-stated scientific prowess to answer your own question about significance of the temperature rise during the period 1880 – 2010. Note that the temperature hump during WWII is an artifact.
    Giles – did you forget attribution again? This isn’t just statistics.”

    I agree. This isn’t just statistics, obviously. That’s the issue : were it just statistics, things would be much simpler.

    Comment by Gilles — 28 June 2010 @ 11:22 AM

    I disagree with both: it is just statistics. Ideology prevents some, such as Gilles, from seeing what the statistics say.

    That’s why they are called denialists, because they deny facts are facts because they don’t fit their ideologies.

  34. 284
    Gilles says:

    ccpo : ” Ideology prevents some, such as Gilles, from seeing what the statistics say.”

    Sorry but I can’t agree. My original question wasn’t ideological at all (and you don’t know my ideology, or even if I really have one). It was purely factual : over which time interval T is the modern variation (average slope on [-T;0] ) outside the statistical distribution of the same quantity computed over all past intervals [-t-T;-t] ?

    I think it is a purely mathematical , well-posed problem. There is no ideology inside- just facts (and no denial of anything since I’m just asking a question).

    If you know the answer, you can tell me the values of T, the slope, and the central value and standard deviation of past values (before a supposed anthropogenic influence), measured in a homogeneous way with the same indicator, to be comparable.

    [Response: Your ideology is irrelevant, because this is just not an interesting question. Temperatures have ranged from snowball earth to the Cretaceous greenhouse, and so nothing that has happened in the recent past is outside the bounds of variability from past climates. So what? If you think that this means we cannot determine to what extent the anthropogenic trends have come out of the background noise for the present day situation, you would be very wrong. See answer first given for why. - gavin]

  35. 285
    Ray Ladbury says:

    Gilles says, “So the tax is supposed to be efficient to reduce the consumption , but the bigger increase of the price of fossil fuels is supposed to do nothing at all, since it would accompany a huge increase of consumption.?”

    Gilles, do you want to try that one again. I couldn’t even diagram that sentence. Maybe try in French.

  36. 286

    Gilles,

    You’re right. I confused the Euro rate (27 per ton) with the Carbon rate (4401/1200 * 100 = $366.75 per ton C).

  37. 287
    MarkB says:

    This comment from Judith Curry is pretty revealing of how her thought process has degraded:

    “Apparently, a number of state climatologists have lost their jobs over their views on global warming, and/or have felt their jobs were threatened. David Legates, Pat Michaels, George Taylor are people i’ve seen mentioned in this context. If you google state climatologists losing jobs, you get a fair number of hits. I don’t have any definitive documentation on this, although I do recall a conversation with Pat Michaels about this.”

    Well gee if I Google “911 conspiracy” I get many more hits. If it’s found on Google or if Pat Michaels says it, it must be true. What concerns me is how she seems to take most things contrarians throw out there at face value, something common with much of the general public with clear ideological leanings, but less common with university professors.

  38. 288
    Patrick 027 says:

    Re 279 ChrisD – thanks

    Re 280 Neil Bates – Actually, the forcing by changing CO2 by some amount is quite well established and contrained to a range around ~ 3.7 W/m2 (tropopause level after stratospheric adjustment) per doubling for the range of CO2 amounts being considered. It sounds like Motl is thinking of climate sensitivity per doubling. There is radiative forcing per unit change in forcing agent, and there is climate sensitivity per unit change in forcing, and the product is climate sensitivity per unit change in forcing agent. The sensitivity has significant (but not infinite) uncertainty because of feedbacks – clouds in particular are a major contributor to that uncertainty. Radiative feedbacks act the same way as radiative forcings, except that they themselves are dependent on temperature changes (the distinction depends on timescale and context; also, in some contexts the feedbacks’ effects are described as radiative forcings – for example, the radiative forcing of the increase in water vapor that would occur for a given temperature increase).

  39. 289
    CM says:

    BPL #278, Gilles;

    Scandinavian carbon tax rates differ by type of fuel, economic sector, and whether or not the emissions concerned also come under cap-and-trade arrangements. In Norway, the highest carbon tax rate is paid on petrol, (US)$57 per metric ton CO2 (2010 info, current exchange rates). The nominal rate in Sweden reached $120/ton CO2 by 2007 (at today’s exchange rates). But industry generally paid only a fifth of that — the full tax was paid in transportation and space heating (CHP excepted), mostly by households. Scandinavian readers may want to fill in or correct me.

    (It goes to show, I think, that a carbon tax need be no simpler or more logical than cap and trade once the politicians have handed out exemptions to their favored industries, at the expense of the ordinary consumer. But at least the Scandinavians are doing something.)

  40. 290
    EL says:

    u have me curious here…

    [Response: Let's leave that for the readers to decide, eh? Or perhaps it should be decided by relative Erdos numbers? ;) - gavin]

    What is your number ?

    [Response: I leave that as an exercise for the reader (there are online resources you can use). But this paper is a clue. ;) - gavin]

  41. 291
    Geoff Wexler says:

    #282 and #276

    I thought that Christy was at one time a “global warming denier” in the sense that he thought that he had established that the troposphere had not warmed very much and that he may have used that as a basis for his world view.

    I find it hard to believe that he used to disbelieve that CO2 was a greenhouse gas or that humans had not increased the amount of it. After all he is a physicist. Those were two of the questions which the Panorama programme got so excited about. The best thing about his other answers was that he stated that he did not really know. (Contrast Lindzen who used to be almost certain in 1995 that the climate sensitivity was tiny with even tinier error bars, Morgan and Keith, 1995 other researchers at the time provided sensible error bars*).

    I agree with Ray. After the disclaimer , he went on to estimate that 1/4 of the recent warming was anthropogenic and that between 10% and 30% of his colleagues agreed with him that AGW is not a problem. He was never asked why. The BBC rarely goes below the surface.
    ———–
    * Why did the BBC fail to show the error bars in the hockey stick graph? It seriously alters the argument.

  42. 292
    Timothy Chase says:

    Secular Animist, earlier you offered some criticisms of Objectivism in comment 220 of this thread. I stated the desire to move the discussion to a different venue because Real Climate really isn’t the place to have an extended discussion of that nature.

    However, I promised to respond. My apologies for the delay — I have had other comments and emails to respond to elsewhere. But I believe I have found a good place if you are still interested.

    It is in Wave — which means that to participate it will be necessary to become a member of Google Wave — assuming you aren’t already. However, if others are interested in the discussion but don’t wish to join Wave at the moment it is also possible to view the discussion in realtime at:

    A wave-based discussion regarding Objectivism
    http://wave.uphero.com/objectivism.php

    It won’t be necessary for you and I to be in the wave at the same time, but assuming we are we will both see each other’s individual key strokes — as will anyone who may be watching from the webpage. Anyway, if you are not interested and have moved on to something else I will of course understand, but if you are interested the opportunity is available.

  43. 293
    Timothy Chase says:

    Secular Animist, one more point regarding the above invitation. While it is public-viewable, for everyone else it is read only as I am not interested at this point in a discussion of indeterminate length.

    As such once you have joined Wave I will need to know your Wave address in order to add you to the discussion as someone with read-write capabilities. My wave address is timothychase at googlewave dot com. However it may be helpful if you also email me at timothychase at gmail dot com just to make sure that you reach me.

  44. 294
    Geoff Wexler says:

    There was yet another thing wrong with Panorama

    As Michael Schlesinger has pointed out in his mailing list, they showed a scale with certainty at the left hand end and “way out” (or some such) at the right hand end. Some people will become confused about the meaning of scientific uncertainty as applied to climate change in particular.

    In other words the implication;

    very uncertain => ‘AGW is wrong’

    is wrong

    I mentioned the converse case of Lindzen in #292. He is not alone.

  45. 295
    Gilles says:

    Gavin :Temperatures have ranged from snowball earth to the Cretaceous greenhouse, and so nothing that has happened in the recent past is outside the bounds of variability from past climates. ”

    OK but this is not exactly my question : it is about the slope, not the amplitude itself. Or more or less equivalently about the amplitude of the power spectrum at a given frequency T^-1. Is the current rate of variation much larger than in the past, as is often claimed? from your answer I understand that you think – like me- “no”.


    So what? If you think that this means we cannot determine to what extent the anthropogenic trends have come out of the background noise for the present day situation, you would be very wrong. See answer first given for why.”

    Well, you may be right, but your statement is obviously much weaker than if the variation could be proved to be outside the natural noise. If I understand correctly, your claim is that your knowledge of the natural noise is good enough so that you can substract it confidently and evaluate properly the anthropic residual. This would be rather obvious if the signal you try to extract were much above the noise – and much less obvious if it is not. Again it is fair to recognize that it is at least disputable.

  46. 296
    Gilles says:

    “Gilles says, “So the tax is supposed to be efficient to reduce the consumption , but the bigger increase of the price of fossil fuels is supposed to do nothing at all, since it would accompany a huge increase of consumption.?”

    Gilles, do you want to try that one again. I couldn’t even diagram that sentence. Maybe try in French.”

    well I’ll do a new try ….

    a) Dangerous GW is supposed to occur above some relatively high amount of burnt fossil fuels, that we should try to reduce , ok?

    b) this high amount is reachable only if we extract unconventional resources, ok?

    c) these resources need to be sold at a high price to be economically profitable, ok?

    d) so the danger does really exist only if we could sell a huge amount of FF at a high price, meaning that the price is NOT supposed to be a problem for the consumer.

    BUT

    taxes are supposed to be efficient to reduce the consumption.

    So why would the consumers reduce their consumption because of high taxes, but not because of high prices?

  47. 297
  48. 298
    SecularAnimist says:

    Gilles wrote: “Dangerous GW is supposed to occur above some relatively high amount of burnt fossil fuels … this high amount is reachable only if we extract unconventional resources, ok?”

    Not OK.

    Dangerous global warming is occurring NOW, the result of the fossil fuels that we have already burned.

    If you don’t understand that, then you have not been paying attention.

  49. 299
    Hank Roberts says:

    Among many refutations of the peculiar notion that scientists should leave policy to the actions of politicians, industry, and market choices, notable are these facts (the first mentioned without attribution earlier in this thread):

    Paul Crutzen in 1995 wrote of

    “… the nightmarish thought that if the chemical industry had developed organobromine compounds instead of the CFCs – or alternatively, if chlorine chemistry would have run more like that of bromine – then without any preparedness, we would have been faced with a catastrophic ozone hole everywhere and at all seasons during the 1970s, probably before the atmospheric chemists had developed the necessary knowledge to identify the problem and the appropriate techniques for the necessary critical measurements.

    Noting that nobody had given any thought to the atmospheric consequences of the release of Cl or Br before 1974, I can only conclude that mankind has been extremely lucky, that Cl activation can only occur under very special circumstances. This shows that we should always be on our guard for the potential consequences of the release of new products into the environment. Continued surveillance of the composition of the stratosphere, therefore, remains a matter of high priority for many years ahead.”
    http://nobelprize.org/nobel_prizes/chemistry/laureates/1995/crutzen-lecture.html

    Or as Feynman put it, also refuting hoping for continued blind luck:

    “The fact that this danger did not lead to a catastrophe before is no guarantee that it will not the next time, unless it is completely understood. When playing Russian r oulette the fact that the first shot got off safely is little comfort for the next.”
    http://www.fotuva.org/feynman/challenger-appendix.html

    Eric responded to someone inline above writing “… If you don’t like the policy, fine, but don’t argue against it on the grounds that the science is wrong, because that’s a non-starter.”

    Non-starting is the goal. In our social system delay and denial are _very_ effective. Scientists don’t realize this until they get clobbered by it in their own field. Consider antibiotic resistance, for example. http://blogs.nature.com/news/thegreatbeyond/2010/06/fda_challenges_use_of_antibiot.html

    “Delay is the deadliest form of denial.” — C. Northcote Parkinson

  50. 300
    Nick Dearth says:

    Apparently it doesn’t matter what experts think, according to some. More fodder for the deniers? http://www.time.com/time/health/article/0,8599,1998644,00.html?xid=rss-fullhealthsci-yahoo


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