A Few Things Ill Considered

A layman's take on the science of Global Warming featuring a guide on How to Talk to a Climate Sceptic.

Tuesday, September 12, 2006

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The Economist on Climate Change

The Economist has a featured article on Climate Change that is getting some attention here and there. It is notable mostly because it means that a real bastion of capitalist Free Market thinking has finally swallowed the eco-nazi propaganda touted by the socialist UN hell bent on world domination via carbon credit trading.

It seems a basically sound piece of writing and I have no general comments or observations. But one passage did strike me and prompts this post:

The establishment of an Intergovernmental Panel on Climate Change under the auspices of the UN was designed to silence the arguments and give policymakers an agreed line on what the future holds. But given how little is known about either the climate's sensitivity to greenhouse-gas emissions or about future emissions levels, that proved difficult. Not surprisingly, the IPCC's latest report, published in 2001, offers a wide range of predicted temperature rises, from 1.40C to 5.80C by the end of this century.

This huge range limits the usefulness of the IPCC's findings to
policymakers.


My problem with this passage is that it makes the very common mistake of equating the uncertainty about climate sensitivity with the uncertainty about emission levels through the coming century. The former is a property of the climate system, beyond our control and with a value that is independent of our influence or understanding of it. The latter is a property of our own behaviour and as such is entirely in our control (in theory, at least, even though the reality of collective behaviour brings quite a few practical limits).

The reason for the error ranges around model runs using a given scenario is due to incomplete understanding of the complex ocean-atmosphere climate system. The reason for the range of greenhouse gas concentrations in the various IPCC scenarios is not to express how unknown the future is, but to provide a guide so that we may choose, to whatever extent possible, what those future emission levels will be.

Therefore I think the conclusion in the cited quote is completely wrong. Decision making is in fact facilitated by having a range of possible outcomes from which to determine a goal and a set of actions.

Labels:

posted by coby @ 9/12/2006 08:49:00 AM  

15 Comments:

  • At September 12, 2006 4:26 PM, Anonymous Anonymous said…

    Please take a look at Roger Pielke Jr.'s post, which criticizes the Economist article for being way too optimistic. http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/000923the_dismal_prospects.html#comments

     

  • At September 12, 2006 5:43 PM, Blogger coby said…

    Yes, I have been on that thread. It prompted the post before this one.

    I think one of my favorite sayings is apropos here: whether you believe you can or you believe you can't, you're probably right.

    You'll also never accomplish a difficult task until you stop asking yourself if you should really be trying anyway.

     

  • At September 13, 2006 11:28 AM, Blogger Heiko said…

    I completely agree with your point, it's quite important to distinguish between the uncertainty in sensitivity and the uncertainty in emissions.

     

  • At September 14, 2006 4:05 PM, Blogger markbahner said…

    Coby,

    You write, "My problem with this passage the(sic) very common mistake of equating the uncertainty about climate sensitivity with the uncertainty about emission levels through the coming century."

    However, it's very clear that The Economist does *not* "equate" uncertainty about climate sensitivity with uncertainty about emission levels.

    They wrote (as quoted by you): "But given how little is known about either the climate's sensitivity to greenhouse-gas emissions or about future emissions levels,..."

    The use of the word "either" makes it very clear that The Economist knows that uncertainty about climate sensitivity is *not* the same thing as (or "equal to") uncertainty about emissions.

     

  • At September 14, 2006 4:39 PM, Blogger coby said…

    Hi Mark,

    You may have a valid grammatical quibble there, but it only means I did not express my point well enough. I'm trying to point out that the is "equating" future emissions and climate sensitivity by using them interchangeably as objective clauses of the same subjective clause. ie: "little is known about climate sensitivity" and "little is known about future emissions".

    My point is that future emissions will not just happen, they will be choosen (to some extent) and they are not a theoretically predictable attribute of some physical sytem following natural laws.

     

  • At September 15, 2006 7:03 PM, Blogger markbahner said…

    You write, "I'm trying to point out that the is "equating" future emissions and climate sensitivity by using them interchangeably as objective clauses of the same subjective clause. ie: "little is known about climate sensitivity" and "little is known about future emissions"."

    I'm not sure what you're trying to say, but The Economist is pointing out that there is uncertainty due to climate sensitivity, and there is also uncertainty due to uncertainty about future emissions, and that those two uncertainties combine to make a an even larger uncertainty. That's absolutely correct. It's well-said, and avoids the mistake many non-technical publications make of implying the only uncertainty is due to uncertainty about climate sensitivity.

    "My point is that future emissions will not just happen, they will be choosen (to some extent)..."

    Well, I assume you probably already know this, but the IPCC TAR scenarios explicitly EXCLUDE any reductions emissions that would occur as a result of any future government actions. So the most *direct* method of "choosing" emissions is specifically exluded.

    You may be right that there is "some extent" of "choosing" in the scenarios (do you know of any place in the IPCC TAR that specifically says that?) but there is also a lot of variation in the scenarios that comes from flat out uncertainty.

    For example, some scenarios have "rapid"*** economic growth and some have slow economic growth. No one would "choose" slow economic growth. (Well, nuts like Hermann Daly might, but they don't count.)

    http://it.stlawu.edu/~pomo/mike/daly.html

    P.S. ***"Rapid" is in quotation marks because all the IPCC scenarios likely underestimate the world GDP per capita in the year 2100 by more than an order of magnitude, and probably even 2 orders of magnitude.

    http://markbahner.typepad.com/random_thoughts/2004/10/3rd_thoughts_on.html

     

  • At September 15, 2006 8:44 PM, Blogger coby said…

    Future emissions will be the result of human actions. Humans have free will. Thus future emissions will not just happen, they will be choosen. Climate sensitivity is a theoretically predictable attribute of of the Earth's climate system and results from the laws of physics.

    The wide range of possible futures that the Economist article complains about do not represent uncertainty in a meaningful sense in the context of decision making. A great deal of it represents consequences of choices we must make now and are there fore exactly the kind of information decision makers need.

    If I go to my financial advisor and ask how much money will I have for retirement do I complain when he says it could be anything from 0 to 1M depending on how much I invest and how the market goes? No, I make choices that improve the odds of having 1M$. The uncertainty in how the market will behave can not be helped, but the other part of the picture is my choice.

    It is a simple point that I should not have bothered spending so much time on, you should get it.

     

  • At September 16, 2006 5:49 AM, Blogger markbahner said…

    "Future emissions will be the result of human actions. Humans have free will. Thus future emissions will not just happen, they will be choosen."

    No, that's not right. The IPCC TAR scenarios explicitly EXCLUDE various governments engaging in treaties and passing laws for the explicit purpose of limiting CO2 emissions.

    Do you agree? Yes or no?

    It is governments engaging in treaties and passing laws to hit certain CO2 emission targets that CHOOSES what future emissions will be. For example, the EU countries and Canada are deliberately CHOOSING to limit their emissions by trying to hit the Kyoto Protocol targets. Those sorts of actions are explicitly EXCLUDED from the IPCC TAR scenarios.

    Do you agree? Yes or no?

     

  • At September 16, 2006 2:32 PM, Blogger coby said…

    For example, the EU countries and Canada are deliberately CHOOSING to limit their emissions by trying to hit the Kyoto Protocol targets. Those sorts of actions are explicitly EXCLUDED from the IPCC TAR scenarios.

    So what? Does that mean it isn't how things work? Nothing you have said has anything to do with the truth of the statement you are attacking: "Future emissions will be the result of human actions. Humans have free will. Thus future emissions will not just happen, they will be choosen."

    This is a fact that is quite independent of how the IPCC arrived at its emissions scenarios.

    I admit I am not very familiar with the SRES scenarios, but a quick look at WG1 did not find any explicit disavowment of gov't controls. Regardless, if this is correct then I can grant you that the passage quoted from the economist would have that in its defense.

     

  • At September 16, 2006 4:10 PM, Blogger coby said…

    Hi Lisa,

    I agree it is quite a good development regardless of any quibbles one might have.

    I'll check out The Great Warming. Is it coming to Canada too?

     

  • At September 16, 2006 5:28 PM, Blogger markbahner said…

    Coby,

    I wrote two statements. For both statements, I asked:

    "Do you agree? Yes or no?"

    You chose the second one--or at least part of it--and respond:

    "So what?"

    Invalid response.

    (Is that a term an artificial intelligence engineer is familiar with? I do not know, since I am an *Environmental Engineer* with an advanced degree and about 17 years of experience analyzing air pollution matters. And I would absolutely NEVER say to you, about a matter of artificial intelligence, "It is a simple point that I should not have bothered spending so much time on, you should get it."

    But I guess that is because ****I**** know areas where I have professional expertise, and areas where I am simply an interested amateur. It would be a good thing if you learned your similar limits.)

    Where was I? ;-)

    Yes, I remember. I asked you twice: "Do you agree? Yes or no?" I want two answers of "yes" or two answers of "no," or one of each. "So what?" is not acceptable.

    Mark Bahner

     

  • At September 16, 2006 6:29 PM, Blogger coby said…

    "So what?" is a rhetorical device that implies that the answer, be it yes or no, is irrelevant to the conversation at hand. As such it is a perfectly valid response. Regardless, I already said that I did not find any explicit disavowment of gov't controls on emissions in the SRES scenarios, but I did not look hard and I am not very familiar with them. Show me a quote.

    Now, why don't you save the snarky attitude, stop wasting my time and make your point?

     

  • At September 17, 2006 2:05 AM, Blogger Heiko said…

    The IPCC do explicitly exclude action taken specifically to control greenhouse gas emissions. I thought you were aware of that, because there was a discussion over on the global change discussion group a few weeks back on the subject.

    Mark is being needlessly difficult, though, and your point I think is fine. We do have a choice, even though the IPCC scenarios explicitly exclude us exercising said choice.

    http://groups.google.com/group/globalchange/browse_frm/thread/c9506f639b6d3fe5/83606210d0c2ac14?lnk=gst&q=gerhaush&rnum=5#83606210d0c2ac14

     

  • At September 17, 2006 5:10 PM, Blogger markbahner said…

    This comment has been removed by a blog administrator.

     

  • At September 17, 2006 5:29 PM, Blogger coby said…

    Sorry Mark, aside from repeating your questions from two comments ago, that comment was nothing but gratuitous rudeness.

    See ya around.

     

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