Listening to the Economists

Nature, in an editorial in tomorrow’s edition, argues that the IPCC is falling short in not including the lateste economists have to offer in it’s next assessment round:

The inclusive nature of the Intergovernmental Panel on Climate Change (IPCC), which is currently preparing its fourth assessment of global warming for publication late next year, has further encouraged economists and climate scientists to work together. The resulting effort has shed useful light on how economic growth, lifestyle changes, international trade, and investment in the energy sector might influence greenhouse-gas emissions. But that’s the easy part. The hard part is untangling the impacts of various possible mitigation actions in order to credibly estimate their actual impact on economics, climate and society.

Unfortunately, for the purposes of its impending fourth assessment, the IPCC won’t manage to incorporate the economists’ latest thinking on these different ’emissions scenarios’. The ‘Special Report on Emissions Scenarios’ that will accompany the assessment was developed in the late 1990s and rests on a number of assumptions that many economists view as outdated or simplistic.


  1. The interesting question (which this doesn’t address – does Nature?) is “how much difference do these new scenarios from the Economists make”? Otherwise… what does it matter?

  2. There’s a discussion of this question in a news story in Nature that accompanies the editorial. My glib summary is that the climate scientists say it doesn’t matter, because the resulting emissions scenarios capture the full range of possibilities. The Susan Solomon quote: “They are perfectly suited to physical tests of how the climate responds to fixed concentrations of greenhouse gas. In the simplified view of science it does not matter how the gas gets into the atmosphere, only how much of it is there.”

    The other side of that argument is that in terms of impacts of climate change on society, it matters a great deal. From Richard Tol: “You can’t use flawed economic scenarios for any meaningful analysis of the impacts of climate change.”

    I think Tol’s argument carries the day. If they was just about climate science, we wouldn’t all be involved in this excercise. The only reason this matters a great deal (rather than merely being an interesting scientific question) is because of its potential effects on human society.

  3. Ummm… but what do the economists say? Do they say “listen to us! we can produce scenarios that are… um… pertty well the same as the ones you already have, but with exciting different assumptions!” or do they say “listen to us! we can produce scenarios outside your range!” If the latter: are they above or below? For the moment, I’m with Solomon: they should stop rabbitting on about flaws in the existing scenarios, and start discussing their new ones. So far, I haven’t seen any public discussion of their pet ones, much less seen them drawn out against SRES. They need to do that.

  4. What the economists and the climate scientists seem to be saying, according to the Nature news story, is that the new scenarios will produce carbon outputs are, as you put it “pretty well the same as the ones you already have.” For Working Group I – the climate itself – that’s fine. But for WGII and III – impacts, adaptation and mitigation – it’s a problem if the economic scenarios are unrealistic. It sounds from Schiermeier’s story as though the economists are discussing their alternative scenarios, but they believe their ideas are essentially locked out of the IPCC process by the use of the old SRES.

  5. William-

    You reinforce the idea that the climate debate should be about global average temperatures. From the Nature article:

    “Economists must learn to bring their knowledge to bear in the discussion, and climate scientists need to realize the significance of economics,” says Edenhofer. Rather than arguing about temperature predictions, “the future battle will be about cost and damages”.

    If you care about costs and damages it seems incredible to argue that flawed economic assumptions don’t matter.

  6. The climate scientist is climate-centric. The economists are econocentric. The policy scientist wants everyone to play nice.

    Wow. Human nature at work. This is why scenario analysis is hard: you have to learn the language of the other person on your team to work well together.

    Going forward into the fyoocher ain’t easy.



  7. Hmm… Dano touches on the Tower of Babel problem so prevalent in climate science from an even wider perspective.

    Economists will have, if their inputs are comprehensive, a more balanced perspective. The paradigm by “climate scientists” is constantly reinforced that climate change is anthropogenic and bad, as if past climate has been stagnant. The economists could put a more realistic perspective on it, that is, not a “how bad is it” but an actual cost benefit analysis, realizing that increasing CO2 would not be a bad thing everywhere, as well as how much it would cost to adjust for changing climate vs. lowering emissions – of course they probably need accurate regional predictions, which are how far off?

  8. No, I still don’t get it. The economists aren’t talking about regional developement (or probably they are, but thats not what we’re on now). They are talking about SRES: which is to say, global CO2 levels (read JFs para 2: thats where all this started). If all they are doing is making finicky little criticisms of the details of exactly what CO2 levels are likely to be or the details of how they are calculated, then they aren’t saying anything very interesting (to me). If they were saying that their new analysis says CO2 levels are going to be much lower/higher, then that would be interesting. But I don’t see them saying that.

  9. You’re correct William. In my view a number of the premises in SH’s comment are incorrect – certainly the ‘stable climate’ argumentation. And I didn’t imply ‘Tower’ in my statement, either. Anyway,

    From an ecological perspective [where I come from], increasing CO2 will likely further stress already stressed ecosystems (stressed, BTW, from human endeavors [endeavours]), and there are no CBAs for after ecosystems flip. But the C after a flip will certainly be bigger than the B, as our economy depends on the ecosystem as it currently exists providing Bs. I see no economic analyses of human endeavors after, say, the southern Great Plains can no longer support graminaceous crops and environmental refugees clog the infrastructure of cities receiving the refugees. Not hard to picture: Katrina.

    The economy, simply put, has no precedent for operating after an ecosystem flip, so asserting fluff such as…well…never mind the silly ‘heat good’ arguments. Such arguments IMHO are not created in thought processes based in Enlightenment principles.

    But back to the point: will anthro CO2 emissions decline in the future, as economists in these arguments aver? And if econos say they will, then let’s simply plug their growth (decline) curves into some GCMs and see what burps out. Can’t be that hard. Why can’t we do that? Economists: make some growth curves.

    CO2 growth curves into GCMs. Sounds like some good doctorate work. For both the econ folk and the clim folk.

    At the very least, it will get the quibblers talking about something else.



  10. I see SH cross-posted while my editor was scanning and correcting my post.

    I just want to reiterate what I implied above: there is very little empirical evidence that areas growing rice or C3 graminaceous crops will continue to do so at the same productivity level in a warmer world.

    And the soils in higher latitudes (‘we’ll just adapt!’) have not had tens to hundreds of years to cycle carbon through at any decent process rate to be able to support intensive agriculture. Not to mention any other mineral. Many row crops are grown at the upper limit of their heat tolerance, and these crops will be less productive in a warmer world.

    And I haven’t even begun to discuss the danger of changing precip regimes. If many of the models are correct, there will be areas in the central Great Plains receiving precip more sporadically, with less soil moisture.

    Flora gains. I know of few ecologists who assert overall gains will be positive. I can’t think of any names off the top of my head.



  11. Dano – whoever you are…

    Let me plink off your opinions. First, stable climate. You apparently have not heard of MBH 98 (That’s all I’ll say about that). Next, I didn’t say you implied anything about Babel – but you unintentionally broached the subject, and William apparently doesn’t understand the other language. Next, your comment that C will be bigger than B after a flip implies first off that there will be a flip, second that you know what will happen if it does. You don’t. Sorry. Nobody does, if one happens. Remember when it was warmer in the Holocene? (well, sorry, I’m not implying you’re that old) The Sahara was a verdant plain.

    Then, something about the Great Plains desert? Where did you get that? Is there an accurate regional model somewhere that I missed?

    Refugees? Possibility, but your opinion that there will certainly be more than there will be without flora gains is not necessarily correct.

    Silly “warm is good”? You apparently are not aware that historically civilizations fell with dropping temperatures, not rising ones.

    Katrina? Please. A category 3 combined with sloppy sea wall construction means you bring up a dogmatic non sequitur. (Plus they’ve been expected to be back)

    With higher CO2 crops require less water, and with higher temperature comes higher precipitation, on average. Certainly with even minor regime changes some areas will get less precipitation, but for the most part precipitation will increase.

    I’m not saying I know everything you say you know is false, I don’t know. But neither do you. The sky is not necessarily falling. We need a lot more research into it – we can increase research in the US by an order of magnitude and it would be a couple of orders of magnitude less expensive than Kyoto would have been.

    Follow the drop in temperature from the peak of the MWP to the valley of the LIA. That is the same rate of fall as Earth fell out of the Eemian. Maybe we rescued our climate. At any rate, imagine what life would be like if we suddenly dropped back to that temperature trend.

  12. Steve H., do you read any peer-reviewed literature? If so, you might try constructing some arguments based on that material as opposed to (apparently) talking points off denialist web sites. Tossing off a bunch of conclusions that most everyone here knows to be simply wrong is just wasting time. You might start by seeing if you can meet Danl’s challenge of naming an ecologist who agrees with your claimed flora gains.

  13. LOL. An act of desperation there – they most certainly are ecologists. And, since I answered your question, maybe you will tell me why you think my conclusions are “simply wrong”. If you have any facts that is.

  14. CO2 Sci’s job is to make CO2 look good, and I used to spend time pointing out how often that site cherry-picked papers. I spent a lot of time at the old Quark Soup debunking CO2 sci claims about flora gains, and John & Steve may remember similar touts there by someone I called ‘lala’.

    Anyway, SH, CO2sci cherry-picks papers. I’ll keep it short by saying that the best understanding is that C3 graminaceous crops are likely going to be less nutritious in a carbon-enriched atmosphere. And tree growth touts in a carbon-enriched atmosphere don’t look too promising, either.

    One can start here.

    Yield losses.

    Precip changes. My personal concern is that plants close their stomata in increased CO2 regimes. Who cares, you say? Less evapotranspiration, less atmospheric moisture, fewer clouds, possibly less rain. Nobody asks the botanists about this (technically, I’m a horticulturalist, but who’s keeping track?).

    One other confounding factor.



  15. Sorry Dano, I think it would be better if you came up with some real arguments. You say “CO2 Sci’s job is to make CO2 look good” – well, I guess I could say your position here is to support Enron et al, because that’s just as true. And, while I’m not saying all or even most climate scientists consider overtly that their next meal depends on their continuation of the “crisis”, you might consider studying the previous subject here on “Ignoring Inconvenient Facts”, and match up the story line of the IPCC’s Summary for Policymakers” with the actual science (including all its listed uncertainties) of the working group reports.

    As far as your “less nutritive” dogma, there is nothing I have seen that these decreases are even within an order of magnitude of the quantity gains.

    That’s the difference between the climate scientists’ narrow perspective which treats all outside their perch on the Tower of Babel as constant, and the (hopefully more comprehensive) economic perspective.

    As far as your alarmist perspective, I’ll quote James Hansen from Science magazine a couple of days ago, concerning the foofaraw of this week:

    “The printed construction provides no hint of my conclusion that large climate change can be avoided via a scenario that includes action to improve energy efficiency and reduce non-CO2 climate forcings.”

  16. Steve H –

    I find your quote from Hansen puzzling, given the central thrust of the AGU talk in question in the Science news article that triggered his letter:

    “The Earth’s temperature, with rapid global warming over the past 30 years, is now passing through the peak level of the Holocene, a period of relatively stable climate that as existed for more than 10,000 years. Further warming of more than 1ºC will make the Earth warmer than it has been in a million years. “Business-as-usual” scenarios, with fossil fuel CO2 emissions continuing to increase ~2%/year as in the past decade, yield additional warming of 2 or 3°C this century and imply changes that constitute practically a different planet. I present multiple lines of evidence indicating that the Earth’s climate is nearing, but has not passed, a tipping point, beyond which it will be impossible to avoid climate change with far ranging undesirable consequences.”

    Hansen argues for rapid near-term efforts to reduce emissions of greenhouse gases. In quoting him here, are you suggesting you agree?

  17. I agree with his quote at the bottom of my last post. I don’t necessarily agree with the opposite though.

    First off I think we can discount the “rapid global warming over the past 30 years” since everybody can’t even agree on whether or not the last 7 have been warming at all. Neither do I believe we have even approached the Holocene Max for temperature (which was the dawn of civilization). But, using the 30 year period conveniently puts us starting at a valley! However, the only fair and logical way to look at it, since we don’t know what’s going to happen for sure in the future, is to look at it from the last peak – 1940. Then, we could, if we also wanted to be pseudoarbitrary, compare that rate with the 30 years before it – but then everyone would find out that the temperature was actually increasing faster in the early 1900’s than it has since, and *somebody* would be out research money. Not that anyone doing research and playing computer games (excuse me, developing GCM’s) would care about feeding their family and stuff like that.

    Seriously, I think Hansen is being realistic by saying CO2 forcing is not necessarily the bad guy everyone (everyone still on that bandwagon anyway) thinks it is. There are a lot of other reasons the climate could be warming.

    My question is why is the lapse rate the moist adiabatic rate, and how much of the 33 deg “greenhouse warming” is therefore thermodynamic and not radiative at all? Strange how I can’t get anyone to answer that question.

  18. Steve H –

    Thanks for your clarification regarding Hansen.

    I think it’s clear that he’s long been a strong advocate for quick reductions in greenhouse gas emissions, both CO2 and other gases, a point he reiterated in some detail in the AGU talk cited in the Science letter from which you drew the quote. He does it again in this morning’s Washington Post. In the quote I cited above, he explicitly blames CO2 for bringing us to the brink of “a tipping point, beyond which it will be impossible to avoid climate change with far ranging undesirable consequences.”

    You obviously have read him differently. It would be helpful if you could cite more of his work in support of your assertion that Hansen is “saying CO2 is not necessarily the bad guy.” The quote you cited is a bit ambiguous, but I sure read it differently than you did. In Hansen’s broader body of work, it’s hard for me to see support for your characterization of his views.

    Perhaps also you could elaborate on your question involving the moist adiabatic lapse rate, as I’ve no idea what you’re talking about. Citations to the literature would be helpful.

  19. Briefly, here’s a thought experiment on the adiabatic lapse rate. This guy is from the other side of the Tower of Babel from the “Radiatives” but the concept is valid – although not exclusively. Adiabatic lapse is mostly why it’s colder at the top of the Sandias than in Albuquerque.

  20. Steve, I think a) you didn’t read this guy’s stuff carefully enough to understand his arguments, b) he’s crazy, and c) you’re trolling. I caught on to all of this when I got to his ascription of past climate variations to changes in atmospheric thickness that he proposes no mechanism for and that violates some pretty basic physics given that the Earth’s gravity and broad atmospheric composition don’t change. There’s a lot more wrong but I think that’s quite enough.

  21. John, there’s no contradiction at all in that Hansen quote. The point is that energy efficiency inherently reduces CO2 emissions (and has other direct benefits), and with this in train the direct emissions focus can be on methane since it has 20x the warming impact of CO2.

  22. I told you he was not entirely correct. So you’re saying you don’t believe there is an adiabatic component to temperature lapse in thte atmosphere then, correct?

  23. SH, your premise is incorrect and your need to purposely misstate what people say to make your argument work isn’t a good tactic on a site where the readers (and owner) are knowledgeable. There is both a dry and moist adiabat component. So what?

    But you don’t understand the issue, which is why you are muddling the argument. Steve Bloom is saying that the guy proposes no mechanism for the phemomenon that is observable. Simple, yet complex.

    And Hansen’s argument has long been that reducing CH4 fraction in the atm is easily doable, and is a good warm-up for the harder job of reducing the CO2 fraction. Because if we don’t start soon, the goop we are putting in the atm may lead to many ecosystems flipping, which would be bad, as our existence is dependent upon ecosystems functioning properly. We have had no experience in trying to adapt on a planet where multiple ecosystems have flipped into an unstable state.

    That is what Hansen said.



  24. Steve B –

    I didn’t say I thought there was a contradiction in Hansen’s quote. I said I thought there was ambiguity. I read it the same way you did. Steve H obviously read it differently. To resolve any ambiguity, it’s reasonable to look at the context (Hansen’s AGU talk), which I think clearly supports our reading.

    Steve H –

    As a journalist covering science for many years, I’ve found it generally unproductive to spend a lot of time on works such as the Geocities page to which you linked. The scientific literature is, for very good reasons, the currency that matters.

  25. Thanks, John and Dano. Just for the record, I think I over-simplified Hansen’s idea in the sense the energy efficiency gets the low-hanging fruit on CO2 emissions, leaving the hard part of the CO2 for after people have formed the right habits (as it were) with efficiency and methane reduction measures.

  26. And Mr Fleck has a good point about the literature. We can check Google Scholar for articles written by the author of the…er…text at the linky being discussed.

    We find no scholarly articles written by the author.

    Huh. Shocking, surely.



  27. Here’s another link to the same concept:

    Steve B – your attempts at ridicule fit right in with bandwagon riders (as do “Dano’s” – shocking really). So does your attempt to cover up that you didn’t back up your other claim in this thread back on the 27th.

    However, I’m not going to lower myself to your ad hominem innuendo. Let’s just stick to the facts. Do you or do you not believe in adiabatic lapse in the atmosphere? How is that temperature lapse ignored in the accepted figure of 33 deg of greenhouse warming?

  28. Believing in the fact that the atmosphere has an adiabatic lapse rate has nothing to do with arguing why the average global surface temp has increased, unless you are trying to argue that earth’s gravity has increased, or the volume of the atm has increased, thus heating the lower atm.

    As the abstract (my sub doesn’t get E&E, I wonder why, maybe because no one reads it) doesn’t state either has happened, this can only be thought of as a joke or some thought experiment.

    Or maybe it’s Sonja trying to fill copy after everyone left and no one would write for them.

    Nor does anything SH links to explain why the fact that increasing CO2 has not warmed the planet. Unless there is a new physics somewhere, in which case why are we not getting a linky to Physics Today?

    That is, why wouldn’t increasing CO2 warm the planet?

    BTW, I used to be a weatherman. We used lapse rates all the time to, say, judge convective potential.

    And thanx for a linky to E&E for an author that wasn’t the first one you wanted to use to share your belief. Perfect, really. I’m sure he’s a Galileo in waiting.

    Yer a hoot, SH.



  29. I’m glad you think I’m a hoot “Dano”. I’m just asking questions, trying to put it all together. The fact that you ignore facts and attempt to chastise me is very telling. I’m just reading Hansen’s quote directly. To shorten it further, he’s talking about his “conclusion that large climate change can be avoided via a scenario that includes action to improve energy efficiency and reduce non-CO2 climate forcings.”

    I never said CO2 forcing wasn’t real. I just don’t know that it’s all that important compared to land use changes and thermodynamics, and I don’t think you do either as you’re just parroting the Enron company line. The thermodynamic factor applies and is just an illustration that anyone who talks about a “runaway greenhouse effect” doesn’t know what they’re talking about. And, I agree that improving energy efficiency and reducing non-CO2 forcings could be included in a “scenario” that precludes large climate change. Reducing non-CO2 forcing is probably good, and increasing energy efficiency is a given with technology improvements.

    However, the apparent squeamishness that power plant investers are displaying by only building for natural gas plants and not coal is costing me over $500 per year since natural gas has gone way up, and I would actually rather pay that money for research than to some energy provider. Too bad the alarmists have people running for cover, thinking the sky is falling.

  30. There’s no facts I’m ignoring. Anyway,

    Excellent that you’re trying to put it all together, SH, but you won’t get all the facts at CO2sci, E&E, geocities, etc. Judging from the ping-ponging/hand-waving and outright wrongness in your argumentation, you’ve got a ways to go, but your curiosity is great start. I’m sure you’ll do well putting it all together when you find the right path. Visit a decent college library and spend time in Journ. Clim., Science and Nature to start. And the links I provided above will start on the ecosystem processes.

    Good luck,


  31. Well, I admit getting that one link from geocities was a faux pas, but you, like Steve B, have yet to disprove what I’ve been saying. So, yes, “there is facts you’re ignoring”. Again, let’s get to those facts, shall we? You keep saying stuff about my “ping-ponging/hand-waving and outright wrongness”, but what exactly is it? Or are you going to just continue your smear campaign because you don’t have any answers?

    What have I said that’s wrong? Let’s try actually talking about that. For example, I say adiabatic lapse is included in the 33 deg C currently attributed by the dogmatists to the restriction to outgoing radiation, but you say it’s somehow different. How is that?

    And, how much has CH4 gone up in the last decade?

  32. What have I said that’s wrong?…you’ve yet to disprove what I’m saying

    That’s because you don’t understand what I wrote.

    Just because you don’t understand the issues doesn’t mean I haven’t disproved what you are saying.

    You’ve implied that the warming is due to adiabatic heating (the two links that you are unable to argue what they say). This is silly. The two links are, simply, thought experiments and stand alone. The sheer weight of the evidence, the theory for which was first proposed in the 19th C and validated decades ago, makes this thought process foolish.

    You imply that CO2 has positive effects (‘flora’ gains). All the links I gave should be read by you, then go to the library to understand the issue.

    Clim Scientists have a paradigm that past climate is stable. No.

    You are confused when you say regional predictions are “how far off”. 1. The future hasn’t happened yet. 2. GCM gains (note date and how many IndyFundeds ignore this).

    You are also confused about arguments about past climate making today…whatever the shills write. None of these arguments consider the CO2 ppmv levels of today; this fact alone makes those argumens moot.

    These complete misunderstandigs (Googleicious), plus your rhetoric of ‘alarmists’, ‘dogmatists’, ‘tower of Babel’, etc. make it easy to see you have a wishy-wish for something to be true.



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  34. “Dano” said:
    “You’ve implied that the warming is due to adiabatic heating (the two links that you are unable to argue what they say). This is silly.”

    Incorrect. I said some of the 33 deg C warming currently attributed to IR radiation retention (aka greenhouse effect) is actually attributable to adiabatic heating. Waaay different. Read it again. Consider convection in the troposphere.

    Then you said:

    “You imply that CO2 has positive effects (’flora’ gains).”

    That’s what plants eat. CO2.

    “All the links I gave should be read by you, then go to the library to understand the issue.”

    All the links you gave me start off with “may” or “could” except Lobell and Asner, whose study is outnumbered 100 to 1 concerning gains – to see them in one spot though, you have to pay for the plant database on the site, since they’re independent and need to eat like everybody else.

    You may want to stay off Eurakalert – they sound a little too much like Alanis Morissette…

    Continuing, climate scientists who believe this is correct:

    certainly believe that past climate is relatively stable – over the last 1000 years anyway. I presume you understand we’re not talking about ice ages and the Holocene Maximum a few thousand years ago when the Sahara desert was green, etc.

    While we’re at it though, in looking at your Wikipedia link you can see the fall from the Medieval Warm Period peak to the Little Ice Age valley, and consider that it was at the same rate as our fall out of the last interglacial, the Eemian. Were we headed for another ice age? Who knows… We’re overdue.

    Onward… You say … erhh I think your message got scrambled?

    Anyway, to summarize, you say the 33 deg C (well, 33.5 deg C now?) is due to greenhouse gases. I dispute that. I think convection and land use changes play a major role as well. Of course, you’re entitled to your own opinion – even if it’s the same as these Kyoto backers and their “associates”:

    who, as I said, are now costing me, and most everybody else, hundreds of dollars a year extra in PNM gas bills that I would much rather pay for research.

    Here’s a good balanced link:

  35. I think convection and land use changes play a major role as well.

    LU changes, sure (cooling effects of albedo changes).

    But convection.

    ’nuff said.

    All done here. Yer all over the place, lad.


  36. Good enough for me. We disagree on whether or not convection plays a role in transmitting energy to space, quantifying the 33 deg C temperature lapse. I say it does, you say it doesn’t.

    But I’m not your lad. You would do well to show respect for others, particularly when you’re on somebody else’s bandwagon – who you don’t even know. You never know when it will come back to bite you.

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