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Avery and Singer: Unstoppable hot air

Filed under: — david @ 20 November 2006

Last week I attended a talk by Dennis Avery, author with Fred Singer of Unstoppable Global Warming Every 1500 Years (there is a summary here). The talk (and tasty lunch) was sponsored by the Heartland Institute, and was apparently enthusiastically received by its audience. Still whoozy from a bit of contention during the question period, a perplexed member of the audience told me privately that he thought a Point/CounterPoint discussion might be useful (he didn’t know I wrote for realclimate; it was just a hypothetical thought). But here’s my attempt to accommodate.

Note: The Points are paraphrases from the slides and my notes from Avery’s talk.

Point. The existence of the medieval warm and the Little Ice Age climate intervals, and the 1500 year D-O cycles in glacial climate, proves that the warming in the past decades is a natural phenomenon, not caused by human industry at all.

CounterPoint. The existence of climate changes in the past is not news to the climate change scientific community; there is a whole chapter about it in the upcoming IPCC Scientific Assessment. Nor do past, natural variations in climate negate the global warming forecast. Most past climate changes, like the glacial interglacial cycle, can be explained based on changes in solar heating and greenhouse gases, but the warming in the last few decades cannot be explained without the impact of human-released greenhouse gases. Avery was very careful to crop his temperature plots at 1985, rather than show the data to 2005.

Point. Hundreds of researchers have published on the Little Ice Age and Medieval warm climates, proving that there is no scientific consensus on global warming.

CounterPoint. Natural and human-induced climate changes both exist. Studying one does not imply disbelief in the other.

Point. Human populations of Europe and India thrived during the medieval warm time, so clearly warming is good for us.

CounterPoint. No one asserts that the present-day warmth is a calamity, although perhaps some residents of Tuvalu or New Orleans might feel differently, and the Mayans may have been less than enthusiastic about the medieval climate. The projected temperature for 2100 under business-as-usual is another matter entirely, warmer than the Earth has been in millions of years.

Point. NASA identified a huge energy hole over the tropical Pacific, which sucked out as much heat as doubling CO2. NASA scientists asked modelers to replicate this, and they failed, by 200-400%, even when they knew the answer in advance!

CounterPoint. This appears to be a reference to Chen et al., 2002. Satellite data from the equatorial Pacific showed an increase in IR heat flux to space of about 5 W/m2 from 1985 to 2005, and a decrease in reflected visible light of about 2 W/m2, leaving a 3 W/m2 change in net heat flux.

Avery’s implicit promise would seem to be that with rising CO2, the heavens will part and let the excess energy out, a Lindzenesque mechanism to nullify global warming. The measured change in heat fluxes in the equatorial Pacific is indeed comparable to the radiative effect of doubling CO2 but the CO2 number is a global average, while the equatorial Pacific is just one region. The measurements probably reflect a regional rearrangement of cloud cover or ocean temperature, a decadal variation with no clear implication at all for the global mean heat budget of the Earth. The global heat imbalance has been inferred (Hansen et al, Science, 2005), and it is consistent with rising greenhouse gas concentrations and transient heating of the ocean.

A word about models in science (as opposed to in think-tank economics, Mr. Avery’s home turf). Models would have little use if they were so easy to bend into any answer we thought we knew about in advance. One can always be critical of models, but there is no model that avoids global warming by parting the heavens, or that is exquisitely sensitive to solar variability but insensitive to CO2, the worlds that Mr. Avery wishes for.

Avery’s talk also dusted off many of the good old good ones, like the cosmic-ray / cloud connection, the temperature lead of CO2 through the deglaciation, the Antarctic warming, the cooling during the period 1940-1970, the now-resolved satellite temperature discrepancy from ground temperatures, and even the ancient CO2 band saturation myth.

In addition to Chen, Avery offered to us the work of Maureen Raymo and Gerard Bond. Bond didn’t think his work cast any doubt on the possibility of anthropogenic warming, neither do Raymo or Chen. Hint: if you want to sound like you know what you’re talking about, the accent on the fourth syllable of foraminifera, not foraminifera.

Point. Environmentalists do what they do because they miss having their mommies reading Grimm’s Fairy Tales to them. They like getting all scared.

CounterPoint. To hybrid-phrase Thomas Jefferson and Richard Feynman, I tremble for humanity when I reflect that nature cannot be fooled. You’re damn right I’m scared.


209 Responses to “Avery and Singer: Unstoppable hot air”

  1. 101
    Lynn Vincentnathan says:

    RE #99. I’m no climate expert, but I see it like this at the macro level: increased GHGs, all things being equal, will increase the global average temp (which doesn’t say exactly how each micro-region will be impacted). The main thing I see working against that would be less sun due to less solar radiance or the earth moves farther away from the sun. Other things, things that cause aerosols, that may temporarily cool regions a bit (volcanoes, forest fires, etc), ultimately will cause warming, since the CO2 will greatly outlast the aerosols & particulates (see the article David Archer wrote on CO2′s longevity up to 100,000 years on RC, http://www.realclimate.org/index.php?p=134). In fact, I think volcanoes are suspects in triggering the end-Permian global warming 251 mya that killed 95% of life on earth (Michael Benton’s WHEN LIFE NEARLY DIED is a good read on that).

    So unless there’s a major sun reduction or planetary move, it’s pretty sure there will be warming with continued addition of GHGs.

    And I for one wouldn’t want to gamble with the life of the biota, including us, on our dear, beloved planet.

  2. 102
    Lynn Vincentnathan says:

    And BTW, we could conceivably live without an economy (which is sort of a new boy on the block, only thousands of years old, at most maybe a million), most of life has done just fine without an economy (exchange of goods & services). However, we do need the environment. The environment is fundamental to life; the economy, contingent.

  3. 103
    Jim Dukelow says:

    Marco Parigi wrote:

    “I will expand on my original point which was that Climate, like weather (or the stockmarket) in general is a chaotic system, with a lot of unknown positive and negative feedbacks.”

    Marco Parigi makes a category error that is fairly common among people who don’t really know what chaos is. Chaos is a property of the output of non-linear dynamical systems. The Earth’s weather is a non-linear dynamical system and one that is almost certainly chaotic. Earth’s climate is various sets, depending on who’s defining it, of statistical measures of the spatial and temporal properties of the Earth’s weather. As such, climate can not be chaotic and is not subject to some of the constraints of chaotic systems, like the lack of long-term predictability. See the Wikipedia entry for chaos theory at en.wikipedia.org/wiki/Chaos_theory .

    Best regards.

    Jim Dukelow

    [Response: You probably don't want to be to dogmatic on this point. As far as we can tell (so far), climate is not chaotic (at least in it's present state). We are sure that models do not have chaotic climates (their statistical properties are stable and well defined), but it is conceivable (though not proven) that as we add more feedbacks to them (vegetation, ice sheets, carbon cycles etc.) they may become so. So it's an open question. This is distinct from the 'weather is chaotic therefore climate can't be predicted' line of argument which, as you suggest, is fallacious. - gavin]

  4. 104
    Eli Rabett says:

    Marco, while arguments from ignorance are popular, you first have to demonstrate that the ignorance is general and not personal otherwise such arguments simply become handwaving. One of the nice things here is that among the moderators one can find people who can debunk the standard “we don’t know anything about” with “yes, we have a pretty good idea of x, see ref” or “the situation is well bounded by y. However, this becomes pretty daunting when a whole pot full of spaghetti is thrown against the wall.

    Without setting myself up as an expert there are some obvious things in your list of claims that are simply not true. For example reductions in CFCs will not disrupt the usefulness of current models. Their effects are included as greenhouse gases. Same for CH4. On the other hand, with CH4 there are problems in the positive direction, because of methane clathrates and permafrost warming that are only loosely bounded (much study going on there), but such unknowns only make things worse.

    The scary thing is that when you sit around and spit ball about what could happen that is not in the models, the most likely things (not that they are probable) are all scary. If you want a short list, start here.

  5. 105
    Pat Neuman says:

    Re: 94

    In his reply, NWS John Jones tells us (in 2003) that under the President’s leadership more than 30 nations came together to establish an Earth observation system aimed at providing scientific data needed to understand our climate.

    Many here at RealClimate may support that position of more data needed, but when will they understand climate change enough to safeguard this world without more delay waiting for more data?

    From my experience, scientists may say they want more data even though they know that more data is unnecessary.

    Extensive soil and water in snow sampling by air, which is operated by NOAA’s National Operational Hydrologic Remote Sensing Center for the NWS North Central River Forecast Center, is wasteful of public money and has contributed to global warming in fuel emissions for many years (1979-current) over hundreds or thousands of flight lines by multiple aircraft.

  6. 106

    Having invited himself to Harvard last week ,Singer delivered a Thanksgiving eve talk on his ‘intuitive ‘ view of the celestial mechanics of satellite capture at the Smithsonian Center for Astrophysics. Asked afterwards about this site he replied :

    “I don’t read Real Climate “

  7. 107
    Steve Bloom says:

    Re #98: Paul G., you cherry-picked my remark in #96. I started out saying “if the authors are correct in their supposition that the rate of melting has greatly increased in the last several years”, IOW everything following was based on the authors’ (not my) *supposition* being true. I don’t agree with their supposition since it is too much in conflict with actual measurements of melting. If you want to apply Occam’s Razor to the situation, consider that sea level measurements have continued a smooth rise. If we simply assume that past trends have more or less continued, there remains very little to explain. Things get complex and inconsistent only if you try to reconcile an inferred sharp stearic drop in sea level with the measured increase.

  8. 108
    Steve Bloom says:

    Re #100: Joel, the models are not perfect, although they are improving at a steady pace. IIRC Gavin has noted elsewhere that short-term fluctuations in ocean temperature (such as the one Lyman and Willis believe they have found) are one of the things the models don’t do well with as yet. OTOH, the models have adequately tracked the long-term trend. As to the data being true, remember that the problem here is that we have a contradiction in the data. The measured sea level rise (pretty reliable), the measured melt (fairly reliable), and the ocean temp measurements (probably somewhat less reliable) need to add up and they don’t. The obvious thought is that there is something wrong wth the least reliable of the measurements; i.e. the ocean temps. Note also Charles Muller’s good point in #79 that we’re talking about relatively short-term trends in metrics that are all subject to substantial decadal variation. That said, the apparent recent increase in melt seems on somewhat firmer ground, which is why it and not the postulated ocean temp decrease has been getting all the attention. We shall see in the next year or two whether it too is a short-term fluctuation rather than a harbinger of more to come. If the atmosphere continues to warm, the safe bet would have to be on the latter.

  9. 109
    Jim Dukelow says:

    In #103, Gavin wrote:

    “Response: You probably don’t want to be to dogmatic on this point. As far as we can tell (so far), climate is not chaotic (at least in it’s present state). We are sure that models do not have chaotic climates (their statistical properties are stable and well defined), but it is conceivable (though not proven) that as we add more feedbacks to them (vegetation, ice sheets, carbon cycles etc.) they may become so. So it’s an open question. This is distinct from the ‘weather is chaotic therefore climate can’t be predicted’ line of argument which, as you suggest, is fallacious. – gavin”

    Gavin, incorrect use of mathematical terminology with a settled and agreed definition IS something I am willing to be dogmatic about. The rest of your response contains an interesting assertion about which I would like to know more information. Have climate scientists actually calculated the Lyapunov exponents of a GCM (or CGMs) to establish that their behavior is not chaotic or perhaps rerun a GCM with a tiny change in initial conditions and shown that the output stays “close” to the previous run? I am talking here about the raw physical output of the GCM (its “weather”) rather than any statistical summary. A problem here, I guess, is that, because of the spatial and temporal discretization in a GCM, even the “raw” physical output includes an effective spatial-temporal averaging.

    Since chaotic dynamics was finally “discovered” in a way that convinced almost everybody, by the chaos in Lorenz’ toy convecting atmosphere, I have had the working hypothesis that weather and any other richly connected non-linear dynamical system with substantial feedbacks would be chaotic. I would appreciate some pointers to the relevant climate literature.

    Best regards.

    Jim Dukelow

    [Response: Let me be clear. Individual trajectories in a climate model are chaotic, just as in the Lorenz model. However, the means of these paths are not (at least in current models). This is equivalent to the stability of the centres of the Lorenz 'butterfly wings' despite the chaos of individual trajectories. - gavin]

  10. 110
    Neal J. King says:

    re: 99, Marco Parigi:

    If you’re sure of your point of view, you should be willing to accept a large bet at 1:1 (limited only by your willingness to deal with a loss), rather than limiting it to $50. For example, I would bet any amount of money that, if I drop an apple, it will hit the ground. I would even accept very unfavorable odds, because I would be sure of winning! A 1:1 ? No sweat.

  11. 111
    Catastrophe says:

    “Marco, I’m sure you’ll be pleased to find out that James Annan, an occasional guest author here, would be very happy to enter into a substantial bet with you along the lines you describe. Please do report back on how much money you’re willing to stake.”

    This is a terrible state of affairs.

    When people pretending to be real scientists are taking bets to shore up their position in lieu of actual evidence.

  12. 112
    dhogaza says:

    “This is a terrible state of affairs.

    When people pretending to be real scientists are taking bets to shore up their position in lieu of actual evidence.”

    Not at all. They’re simply proposing to make money on their belief of the actual data.

    As a skeptic, you’re prepared to back up your dismay with real money to spank these dudes, right?

  13. 113
    Marco Parigi says:

    it is conceivable (though not proven) that as we add more feedbacks to them (vegetation, ice sheets, carbon cycles etc.) they may become so. So it’s an open question. This is distinct from the ‘weather is chaotic therefore climate can’t be predicted’ line of argument which, as you suggest, is fallacious.

    I didn’t really think I was saying anything particularly controversial by asserting that climate will be shown to be “chaotic”. Since that part of my argument rests on this assertion, so does my argument that Avery had some useful insights amongst some otherwise biased (against global warming scientific consensus) statements.
    However, I am very concerned that the moderators and other contributors to this forum are dismissive of Economists in general. For activists in this arena, economists should be entrusted to demonstrate the best ways to invest money in carbon reductions, cost/benefit analysis of various projects as well as realistic estimated economic consequences of global warming. They are the experts to do with these questions, but few policymakers are listening to them when formulating environmental policy. This is in part due to statements in sites such as this. eg. “This person’s field of expertise is economics, not environmental science.” The result is that other statements that other economists say such as “A flat global carbon tax is infinitely more effective at reducing GHG’s than the myriad of solar/wind subsidies applied, and is virtually costless in comparison” will also be dismissed to the detriment of the environmental movement.

  14. 114
    Neal J. King says:

    re: 111, Catastrophe:

    a) Annan IS a real climate scientist. You can look him up in Google.

    b) There is a long history of scientific experts making bets, when it’s currently impossible to prove a point either way. Example: in the arena of General Relativity, such renowned experts as Stephen Hawking, Chandrasekhar, John Wheeler, and Kip Thorne have had bets among each other. It’s just a way of saying, “Even though I can’t give you proof that you accept as incontrovertible at this moment, I’m sure that in x (x = 5, 10, whatever) years, that you’ll have to agree.”

    Usually the stakes are much lower than the thousands that Annan has put up. But that’s because the bet is much friendlier: No one on one side of a general-relativity argument thinks that the fate of the world (or of the economy) depends on the result turning out one way or the other, so no one accuses the other side of operating in bad faith.

  15. 115
    Neal J. King says:

    re: 113, Marco Parigi:

    GW is a topic for which there are both scientific and economic aspects. There is no problem in respectfully using input from both areas of expertise, as long as it is clear which aspects of the input apply to which aspects of the topic. An economist’s attempt to apply chaos theory to climate modelling should be regarded as similar to a climate modeller’s attempt to apply pricing theory to carbon credits: strictly amateur-hour.

  16. 116
    Jim Dukelow says:

    In #113, Marco Parigi wrote:

    “I didn’t really think I was saying anything particularly controversial by asserting that climate will be shown to be “chaotic”. Since that part of my argument rests on this assertion, so does my argument that Avery had some useful insights amongst some otherwise biased (against global warming scientific consensus) statements.”

    Well, live and learn — or, perhaps not.

    The general dyspepsia toward economists writing on climate issues is due to their pretending to know things they do not know. Case in point, the over-simplistic nature of economic models and the poor empirical basis for their structural assumptions and critical data.

    Best regards.

    Jim Dukelow

  17. 117
    Hank Roberts says:

    >since the climate models didn’t predict this ….

    You start with a wrong assumption and demand a needless choice between two true facts.
    Treat this as science, not politics, and check what you’re told. Your source was wrong.

    As an example, I’ve put your phrases into a Google search. Click here:

    http://www.google.com/search?hs=DVM&hl=en&q=%2B%22climate+models+predict+increased+variability%22&btnG=Search

  18. 118
    pete best says:

    The climate would need to be in a far from equilibrium condition to become chaotic and 3 deg C hardly implies that does it?

  19. 119
    Dan Hughes says:

    Comments 103, 109, and 118. These issues are somewhat outside my ranges of expertise, so I hope RC will allow me to attempt to add to this discussion.

    Mathematical chaos is basically understood within the framework of simple algebraic and ordinary differential equations. The actual existence of an attractor for the famous three-equation Lorenz equations, developed in the 1960s, was only proven in 1999 (I think). The statement that “weather is chaotic” seems to be invoked from the almost uncountable number of studies associated with the original Lorenz three-equation “model” and subsequent slightly more complex “models”. The original lorenz equations are well-known to be a severe truncation of an already over-simplified representation of a very complex physical process. At its very best the original three-equation model describes only the onset of bulk fluid motion for the case of a fluid layer heated from below under the influence of gravity acting transverse to the fluid layer. A less-dense fluid under a more dense fluid is known to be physically unstable. The three-equation model might approximate the initial unstable fluid motion at the end of the conduction-controlled heating of the fluid, and nothing more. It does not, because it cannot, have any connection to reality following the onset of fluid motion.

    The chaos shown by the model is exhibited for only certain values of some of the parameters (constant coefficients in the ODEs) of the model. The model equations also exhibit stable solutions for other values of the parameters. I have not found papers that report validation of any of the various Lorenz models by comparisons of predictions with experimental data. A very important aspect of the validation would be the necessity of using experimental data for which the conditions match the ranges of the values of the parameters in the model equations for which the equations exhibit chaotic behavior. For the case of the original three-equation model validation would consist of showing that the model predicts the onset of fluid motion following a conduction-controlled phase. For applications to weather the equations would also be required to be a correct description of the fluid motion following the initialization of the motion.

    Generally, analytical/theoretical certainty about chaos is based almost entirely on simple iterated algebraic maps and some ordinary differential equations. Less is known analytically/theoretically about chaos within the realm of partial differential equations. Even less (nothing, maybe?) is analytically/theoretically known about chaos for systems of equations comprised of algebraic equations plus ordinary differential equations plus partial differential equations within a solution domain that contains discontinuities in both the physical dependent variables and the independent spatial variables (some of the algebraic equations might also contain discontinuities). And not to mention the possibility of discontinuities in the first derivatives of some of the equations. Nothing, and I do mean nothing, has been analytically/theoretically established about chaos within the realm of approximate numerical “solutions” to the discrete approximations to the systems of equations as described in the previous sentence. Finally, nothing about chaos can be established or learned from the results displayed by calculations of the computer codes that contain the numerical methods and for which it is a known fact that independence of the discrete approximations used in the numerical methods can not be demonstrated.

    In this respect, the question in #109 above has not been answered. But I think that I can state with a great deal of certainty that the Lyapunov exponents have not been, and very likely will not ever be, determined. Again I think that this must be done within the framework of the original continuous equation system composed of algebraic equations, ODEs and PDEs. It cannot be accomplished within the framework of an exceedingly complex computer code in which only approximate “solutions” to discrete approximations to the original continuous equations are obtained and accepted. The fact that only approximate “solutions” are the standard is proven by the fact that independence of the calculated results from the discrete approximations has never been demonstrated. That is, the need for convergence of the solutions of the discrete approximations to the continuous equations, the very standard for numerical methods, is dismissed with hand-waving. Convergence follows from consistency and stability. These latter two foundations of numerical solution methods also do not seem to receive due attention in the AOLGCM world.

    The difficulties of obtaining accurately converged numerical solutions to systems of non-linear PDEs which describe inherently complex multi-state, multi-scale physical phenomena and processes are known to be enormous. Pathology behavior of even a simple, single, non-linear ODE, within the framework of a well-posed problem, is easily demonstrated to arise from the numerical method alone. The computed results are simply wrong. Given what is for all practical purposes the uncountable number of degrees of freedom for numerical solutions of a system composed of algebraic equations plus ODEs plus PDEs, correctly fretting out any chaotic responses based on numerical results alone seems to be beyond reach, and reason.

    Additionally, given a system for which chaotic response is known to be a proper response and within the domain of the parameters for which chaotic behavior is known to occur, the initial portions of two calculations are known to be “nearer” than in the later portions of a calculation. For climate-change calculations with temporal scales of 100 years, how is it known that the results of the calculations that make up the ensemble do in fact represent the same physical states. Truncation errors, which will always be present in numerical solution methods, are a way for “small” perturbations to be introduced into the response at each and every discrete time step. The stopping criterion for even a single non-linear algebraic equation is a simple and straightforward example. The exact function is not represented by such iterative solutions. How is it known that these small discontinuities do not induce a chaotic response? Shadowing breakdown, introduced by “errors” of the size of truncation errors in numerical solutions, has been shown to be possible. The computed trajectory has no relationship whatsoever to the correct trajectory.

    Very importantly, none of the issues mentioned above begin to address the question of how is it known that attractor(s) even exist in a system composed of algebraic equations plus ODEs plus PDEs. And for what ranges of which parameters a chaotic response is expected to occur.

    The usage of “chaos” seems to be backwards between weather and climate-change. The weather calculations cover a very significantly shorter temporal range so that the individual calculations will have diverged less than for the climate-change case. I suspect that due to the relatively short temporal range the solution of the “weather” problem is governed by the initial conditions. And by this I do not mean that the response is sensitive to small changes in the initial conditions. The initial conditions will not satisfy the equations of the model, so deviations from the initial condictions are expected to be the norm. The path of the calculated results are then determined by the equations programmed and solved. An algebraic switch in a parameterization, for example, may or may not be activited.

    So, what is the theoretically proven basis for using very-long range climate-change calculations in ensemble averaging? How is it that we know that mathematical models for weather are correctly calculating chaotic response? How is it known that a single trajectory from an AOLGCM code is chaotic? Where are the reports and papers that address these questions within the framework of the continuous equation system used in a given AOLGCM?

    [Response: First point, statements about climate and weather models do not equal conclusions about the real world - though to the extent they have similar behaviour and responses, one can infer similar conclusions, but those are obviously less certain than statements about models. Given that, any climate or weather model is a deterministic mapping of some state space at t to another at t+1. You can easily demonstrate that this is sensitive to small perturbations in initial conditions and you can indeed calculate Lyapunov exponents (the decorrelation time is on the order of two weeks). Thus the weather in these models is indeed chaotic by any reasonable definition. As far as we can tell, this behaviour exists at all resolutions and degrees of complexity above a certain threshold, and so it is a reasonable inference that this applies to the real world also. (As an aside, no-one thinks of the Lorenz model as a 'model' of the real world. It is just a simple(r) system with which you can illustrate certain phenomenology). Whether the continuous equations are chaotic is an open question, though most people would bet that they were - but since it is impossible to construct such solutions it is impossible to say, and therefore not a particularly interesting question. Statements about the non-chaotic nature of climate model long term changes is based on the empirical observation that they are independent of the initial conditions. The climate sensitivity for instance can be calculated over and over with different 'weather' and it will converge to the same answer every time. - gavin]

  20. 120
    Marco Parigi says:

    Jim Dukelow says :The general dyspepsia toward economists writing on climate issues is due to their pretending to know things they do not know. Case in point, the over-simplistic nature of economic models and the poor empirical basis for their structural assumptions and critical data.

    Thank you. This is exactly the kind of broad generalisations about economists which I am complaining about. Instead of saying that “This is an economist so don’t listen to him” I suggest instead to say something like “Listen instead to economist X who is saying “Economic models are showing that money spent on wind/solar subsidies are wasteful compared to spending the same amount on direct carbon reduction (buying voluntary carbon credits or “carbon neutral” type products). Removal of fossil fuel subsidies and higher price expectation of electricity would also be helpful.” This message is not getting to the voters in Western countries, and it is because of this general dyspepsia which you seem to be propagating.

    Instead of picking on economists as a class, highlight statements where they are talking in their field of expertise and propagate those!

  21. 121
    Chris Schoneveld says:

    Ok, now a question that burdens my environmental conscience. I raised the same question at the Gristmill Blog. Let’s assume (here I am playing devil’s advocate or with fire since this would leave the global warming fraternity with egg on their face) that after a number of years there is irrefutable scientific proof – or scientific consensus, if you like – that global warming is not caused by humans but a natural phenomenon, should we try to interfere with nature or manipulate our climate (assuming we find a way to do so) in order to “save” humanity and those ecosystems that are now said to be in grave danger?

    [Response:The origin of the present-day warming tells us whether the future will be gravely dangerous or not. If the present-day warming were purely natural in origin, then it probably wouldn't get much more extreme than it already has. We could assume that the Earth would stay within the natural envelope of climate variability from the recent past. OK, that could mean a sea level rise of a few meters, to bring us up to the level during the last interglacial time 120 kyr ago. But the forecast for the coming century, including the effects of rising CO2, put the temperature outside the range of natural variability over the past several million years. I think Avery's trick was to muddy the distinction between the present-day warmth, which is comparable to the recent past and arguably even beneficial, with the forecast for the coming century, which is neither of those things. David]

  22. 122
    Neal J. King says:

    re: 120, Marco Parigi:

    RealClimate is a forum focused primarily on the scientific, not economic, issues of climate change. Why do you think the participants here would be in any position to identify an economist’s particular area of expertise and know whether he is talking about? So why should they evaluate or promote any specific economic policy whatsoever in this site?

    Dukelow’s pique at economists in general may not be quite fair – but in the context of your suggestion that economists can predict temperature trends better than climate modellers, it’s quite understandable.

  23. 123

    Re “I will expand on my original point which was that Climate, like weather (or the stockmarket) in general is a chaotic system”

    Climate, in general, is not so much a chaotic system as a deterministic system. You may have climate confused with weather.

  24. 124
    Neal J. King says:

    re: 121, Schris Schoneveld:

    If it were to turn out that GW really were caused by natural phenomena, an immediate question would have to be, Is there anything that we have the ability to effect that would stop it?

    If the answer were No, then there would be nothing to be done.

    If the answer were Yes, then it would make sense to respond to it as we would to any large natural threat: try to forestall it. For example, if a large asteroid were heading in our direction, and we thought we had the capability of dispersing or diverting it from impacting the Earth, I don’t think there would be too many people arguing for “letting nature take its course”.

    Does this vitiate the case for protecting the environment against AGW? I don’t think so: When we protect the environment, we are also protecting certain “services” the environment provides to us: biodiversity is not only an esthetic service, but also provides a source of new biological & medical capabilities, and also is a source of biological robustness. Ultimately, protection of the environment is not about returning to a mythological pristine state of nature, but about protecting the sustainability of our own existence.

  25. 125
    Jeffrey Davis says:

    re:121

    Would the origin of a house fire — lightning vs. arson — keep you from fleeing?

    [Response:A better analogy would be a real house fire versus a false alarm. If your smoke detector were faulty, went off for no reason, it would probably mean your house is not really on fire. Present-day warmth is the alarm, not the fire. The fire is yet to come. David]

  26. 126
    teacher ocean says:

    Re:#74

    I didn’t mean to come at anyone with bare knuckles. But thanks for your candor David. I just think the discussions could be more focused.

    Re #125: I was under the impression that we were sure the warming was related to anthropogenic influences. Is there any doubt about that other some denialists screaming “tell me it isn’t so.”

    [Response:IPCC says we're sure. We have measured a large climate forcing from greenhouse gases, and not much from natural agents. The temperature rise can be explained quantitatively as resulting from the gases, but if we wish the gases away, toss out the forcing that we know exists, then we wouldn't be able to explain the warming. By the usual rules of scientific evidence, it's case closed. David]

  27. 127
    Doug Watts says:

    Point. The existence of the medieval warm and the Little Ice Age climate intervals, and the 1500 year D-O cycles in glacial climate, proves that the warming in the past decades is a natural phenomenon, not caused by human industry at all.
    —–

    This is the type of “point” that as a climate science layman makes me immediately suspicious of the speaker’s motives. It is such an obvious bait and switch, very much like a magician distracting your attention for a short moment to reach for a card in their back pocket. Why not just say that because things fall I should not be worried if you throw me out the door of an airplane? It’s really that stupid.

  28. 128
    Doug Watts says:

    “Point. Human populations of Europe and India thrived during the medieval warm time, so clearly warming is good for us.”
    —–
    This contains two blatant fallacies of logic.

    The first is the fallacy of embedded, unproven assumptions. The statement above, for it to be true under its own standard of construction, requires that the contemporary warming is identical to earlier warmings in all fundamental aspects. Yet, the statement does not prove this nor does it attempt to. It simply “says” it is the case without any proof. But if this assumption is not true, the entire argument falls apart.

    Second, and most obvious, is that even if true, this “fact” is completely irrelevant to people and other critters who live somewhere on Earth other than Europe or India. This is cherry-picking.

    [Response:Just to be clear, this "Point" was my paraphrasing of a statement made by Avery. David]

  29. 129
    Doug Watts says:

    Ok, now a question that burdens my environmental conscience. I raised the same question at the Gristmill Blog. Let’s assume (here I am playing devil’s advocate or with fire since this would leave the global warming fraternity with egg on their face) that after a number of years there is irrefutable scientific proof – or scientific consensus, if you like – that global warming is not caused by humans but a natural phenomenon, should we try to interfere with nature or manipulate our climate (assuming we find a way to do so) in order to “save” humanity and those ecosystems that are now said to be in grave danger?
    —–
    I respect the sincerity and intent of the question, but it completely misses and obscures the critical scientific issues here, as most “what if?” questions do. An analog would be, “what if we find out 50 years from now that smoking does not cause cancer?” Or another: “Because it is possible that Einstein’s theories of general and special relativity may be refuted in 50 years should we really design space craft today in accordance with those theories?

    Questions framed like the above are unanswerable because right now — by definition — we don’t know what we will know 50 years from now.

    This fact is the genesis of the Precautionary Principle. Google it.

  30. 130
    Jim Steele says:

    #108 SB wrote “The measured sea level rise (pretty reliable), the measured melt (fairly reliable), and the ocean temp measurements (probably somewhat less reliable) need to add up and they don’t. ”

    I am not at all convinced by your reliability rankings. Ocean temperatures appear to me to be the most direct observation. Sea Level measurements require modeling of tectonic forces. Along with Glacial Isostatic Adjustment estimating glacial rebound effects, how much does the 2 mm/year westward movement of the North American Plate affect the 20 cm greater height of the Pacific? If you squeeze your coffee cup the level of coffe rises, but the volume stays the same. And sea level is mostly a proxy for volume changes. Does the growing Atlantic basin off set the rise in the Pacific? Or does the growing volcanoes at the mid-Atlantic ridge offset chnages of a widening Atlantic. Granted that I have an elementary understanding of this, but actual sea level determination appears to be a much more complex and derived metric. Thus there is greater room for more errors and amplification of errors. And I am not sure why meauring melt would more reliable than an Argos measurement? Please explain.

  31. 131
    Ike Solem says:

    Regarding the first point about the natural variability of climate, the Little Ice Age, and so on – isn’t this itself evidence of the high sensitivity of the climate system to relatively small forcings? Lindzen has always tried to portray the climate system as a ‘stable equilibrium system’ but the reality seems far closer to what Spencer Weart called “An Erratic Beast”.

    Now if the climate system is quite sensitive to small forcings, and since human activity is undoubtedly a large forcing (which noone has to debate anymore, hopefully), isn’t that itself strong evidence that we are seriously affecting the climate system? Unlike volcanoes, whose effects are temporary, we’ve been applying a steadily increasing forcing for over a century. How do the denialists get away with using this example as evidence of a lack of a human effect?

    Regarding the several posts about ‘economic theory’, let me offer a practical example of economic reality. In Farmington, New Mexico, there is a gargantuan coal-fired power plant (you can see a picture of the facility and a rundown of the ownership here). It was built by Bechtel Corp. in the 1960′s, and operates without any regulations. This facility is supplied with coal by Peabody (the nation’s largest coal producer). It sells 48% of its electricity to California, and those of us who pay attention to these things are wondering if California’s new anti-global warming bill, AB32, will force a halt to this. Shutting down this coal-fired system and replacing it with solar power would result in large reductions in CO2 emissions (it emits about 15 million tons of CO2 to the atmosphere per year, plus about 40,000 tons of NOx, plus mercury and sulfur dioxide).

    However, shutting the plant down and building a solar replacement would cause economic pain to the owners of Peabody Coal and to the owners of the power plant, who make a lot of money supplying electricty to the lucrative California market. This is why the American Enterprise Institute (whose director is also the CEO of ExxonMobile) are offering $10,000 for ‘respected climate scientists’ who will serve as climate denialists. That’s the real economic picture.

  32. 132
    SecularAnimist says:

    I am not surprised to see Dennis Avery joining the ranks of the shrill AGW denialists. I am familiar with his work at the Hudson Institute where he has made a career of attacking organic agriculture, for example with the blatantly false claim (i.e. the lie) that organically produced produce is extremely dangerous to eat (compared to crops that are drenched in toxic pesticide residues). He has been peddling fake, phony, bogus “science” to the general public on behalf of various corporate interests for a long time. There is something of a connection between his shilling for the pesticide and chemical fertilizer industry (against organic agriculture) and the fossil fuel industry (against AGW) since most pesticides and chemical fertilizers are derived from the same sources as fossil fuels.

  33. 133
    SecularAnimist says:

    In the previous comment I wrote about Dennis Avery’s “blatantly false claim that organically produced produce is extremely dangerous to eat (compared to crops that are drenched in toxic pesticide residues).”

    I recommend the article at SourceWatch.org about the history of this particular lie from Dennis Avery. It illustrates the depths of this man’s dishonesty and corruption.

  34. 134
    Lynn Vincentnathan says:

    Re #121, 125, 126 & David’s replies, I’m not sure there is no net harm from the present warming.

    My impression is that there is net harm & death, though some of the harms might not (yet) meet scientific or 95% certainty, such as harm/death from Katrina. I’m thinking AGW-added intensity of droughts around the world, flooding, extra heat deaths, disease spread, storm harm — of course subtracting out those guys who didn’t die from snow-shovelling because there wasn’t any snow, etc.

    Species extinctions are also greatly on the rise, and though a particular frog specie going extinct may not impact our human well-being much (except, perhaps, for more disease-carrying mosquitoes), biodiversity is so complex (according to my understanding of it), that our elimination of at least some species might have far-reaching repercussions harming our human well-being. We’re really playing with fire and kerosene here.

  35. 135
    SecularAnimist says:

    Lynn Vincentnathan wrote in #134: “… I’m not sure there is no net harm from the present warming. My impression is that there is net harm & death …”

    According to the World Health Organization your impression is correct:

    Climate Change Death Toll Put at 150,000
    by Christian Plumb
    December 11, 2003
    Reuters

    MILAN – Global warming killed 150,000 people in 2000 and the death toll could double again in the next 30 years if current trends are not reversed, the World Health Organization says.

    One heatwave killed 20,000 people in Europe alone this year, the WHO said, launching a book on health-weather links at a U.N. environment conference.

    Climate change, linked by scientists to human emissions of gases such as carbon dioxide from cars and factories, is causing more frequent floods and droughts and melting ice caps.

    “An estimated 150,000 deaths…were caused in the year 2000 due to climate change,” the study said. A further 5.5 million healthy years of life were lost worldwide due to debilitating diseases caused by climate change, it said.

    “The 1990s were the hottest decade on record and the upward trend in the world’s temperature does not look like it is abating,” it said. “In Europe this past summer, for example, an estimated 20,000 people died due to extremely hot temperatures.”

    The situation will worsen if climate trends continue, WHO experts said at a news conference to launch the book.

    “We see an approximate doubling in deaths and in the burden in healthy life years lost” by 2030, said WHO scientist Diarmid Campbell-Lendrum.

    [...]

    [Although of course this isn't the *net* toll, since its only the negatives, and doesn't mention lives saved by warmer winters... -W]

  36. 136
    Chris Schoneveld says:

    #129 DW wrote: An analogy would be, “what if we find out 50 years from now that smoking does not cause cancer?”

    I would have no problems answering that question: smoke as much as you like in 50 years from now, of course. I didn’t ask what you would do NOW if you hypothesize that you turn out to be wrong later on.
    Therefore, It has nothing to do with the precautionary principle, because that only applies when you are uncertain but don’t want to take the risk of doing nothing. I asked what you would do THEN when you have established certainty.

    I am more inclined to follow King’s(#124) reasoning yet there is a big difference if we are dealing with a warming trend that may persist for millennia. Do we have the right to interfere with nature in that case? We are not talking about single calamitous events like asteroid impacts.

    The questions I raised is not quite hypothetical since I cynically believe that we won’t be able to reverse any trend by any CO2 emission management scheme which prompts the question shouldn’t we accept the inevitable and start thinking how to manage the consequences (that is also a precautionary attitude). I am sure if we were indeed convinced that global warming is natural that we would immediately start thinking how to minimize its effect on our world rather than trying to interfere with the natural trend. So here I have cleared my conscience and given the answer to my own question.

  37. 137
    Paul G says:

    ==== Comment # 131 by Ike Solem ====

    However, shutting the plant down and building a solar replacement would cause economic pain to the owners of Peabody Coal and to the owners of the power plant, who make a lot of money supplying electricty to the lucrative California market. This is why the American Enterprise Institute (whose director is also the CEO of ExxonMobile) are offering $10,000 for ‘respected climate scientists’ who will serve as climate denialists. That’s the real economic picture.

    ====

    Your simplistic blame scenario is not true, and not helpful. At present, large scale solar and wind would cost us, the consumer, much more money. As little as you like coal plants, they perform a common good, in that they supply affordable, reliable electricity to the masses. AGW may change this, but this ongoing demonization of businesses that legally supply us with energy is somewhat shameful.

    And to suggest that any scientist could be bought for a piddly $10,000 is equally ludicrous. The suggestion that the tiny sum of $10,000 would upset the consensus of AGW is not even plausible.

    Demonizing big businesses engaged in legal, lawful activities is mostly psychological projection; where we absolve ourselves of any personal responsibility and thrust any necessity for ourselves to take any personal action by foisting any and all blame onto others.

    Regards,

  38. 138
    Paul G says:

    ==== Comment # 131 by Ike Solem ====

    However, shutting the plant down and building a solar replacement would cause economic pain to the owners of Peabody Coal and to the owners of the power plant, who make a lot of money supplying electricty to the lucrative California market. This is why the American Enterprise Institute (whose director is also the CEO of ExxonMobile) are offering $10,000 for ‘respected climate scientists’ who will serve as climate denialists. That’s the real economic picture.

    ====

    Your simplistic blame scenario is not true, and not helpful. At present, large scale solar and wind would cost us, the consumer, much more money. As little as you like coal plants, they perform a common good, in that they supply affordable, reliable electricity to the masses. AGW may change this, but this ongoing demonization of businesses that legally supply us with energy is somewhat shameful.

    And to suggest that any scientist could be bought for a piddly $10,000 is equally ludicrous. The suggestion that the tiny sum of $10,000 would upset the consensus of AGW is not even plausible.

    Demonizing big businesses engaged in legal, lawful activities is mostly psychological projection; where we absolve ourselves of any personal responsibility and thrust any necessity for ourselves to take any personal action by foisting any and all blame onto others.

    Regards,

  39. 139
    Marco Parigi says:

    Re: MILAN – Global warming killed 150,000 people in 2000 and the death toll could double again in the next 30 years if current trends are not reversed, the World Health Organization says.

    In an earlier post I was criticised for asserting that climate will be shown to be “chaotic”. In one of the replies, scientists in general do believe weather to be “chaotic” by scientific definitions.
    Weather kills people, not climate. Scientists are on tenuous ground if they attribute deaths due to weather events on the climate changes. The causal relationship is difficult to demonstrate and impossible to “prove” scientifically. I will now assert that in a chaotic system (weather) the associated statistical averaging (climate or climate change) should not be attributed to either the frequency or severity of events in the chaotic system. I challenge the scientists on this forum to show causal evidence from the historical record to demonstrate this link suggested; or otherwise reject this statement by the WHO as unscientific.

  40. 140
    Lynn Vincentnathan says:

    RE #135, I suspect that WHO has grossly underestimated the actual death toll, due to the difficulties in scientifically, with a high level of certainty, establishing links from the warming (or CO2 emissions) to the harms. Someone informed me the 160,000 deaths/year only reflected deaths from disease spread due to GW. Farmers in India & Australia are committing suicide due to the droughts, but I doubt those are included in the death tolls. Do they even include at least a portion of the people dying from drought in Africa?

    Then there are the myriads of harms & death from other problems related to the same GHG-producing actions (such as coal & oil burning)….acid rain, local pollution, etc.

    [Okay, there are benefits from burning fossil fuels, too, like a high lifestyle, but I'm so happy I'm on 100% wind power. Hope others that can afford the $5 or so extra per month would also do the same where it's available.]

  41. 141
    Tosh says:

    Re: #137

    ‘Your simplistic blame scenario is not true, and not helpful. At present, large scale solar and wind would cost us, the consumer, much more money. As little as you like coal plants, they perform a common good, in that they supply affordable, reliable electricity to the masses. AGW may change this, but this ongoing demonization of businesses that legally supply us with energy is somewhat shameful.’

    This appears to be a simplification of what is a cost and what is a common good. I am guessing that if the full lifecycle ‘costs’ and ‘common good’ of electricity sourced from coal power were fully accounted for and understood by consumers, consumers would be very happy to ‘pay the extra cost’ of solar and or wind power.

  42. 142
    Dan says:

    re: 137.”AGW may change this, but this ongoing demonization of businesses that legally supply us with energy is somewhat shameful.”

    Clearly some perspective on what is “shameful” is in order. DDT was “legally” applied on agriculture for many years with significant negative consequences on the ecosystem. Fortunately it was eventually regulated.

  43. 143

    Re “Species extinctions are also greatly on the rise, and though a particular frog specie going extinct may not impact our human well-being much (except, perhaps, for more disease-carrying mosquitoes), biodiversity is so complex (according to my understanding of it), that our elimination of at least some species might have far-reaching repercussions harming our human well-being.”

    Lynn, you’re right that this is a serious problem, but I don’t think it’s directly related to global warming (though it increasingly will be as the world heats up). I believe the main thing now driving species extinction is the fact that humanity is expanding its numbers and its use of resources. In the short term, the biosphere is a zero-sum game. Animals are dying out because we’re eating their food.

  44. 144
    Doug Watts says:

    RE: #137. Your simplistic blame scenario is not true, and not helpful. At present, large scale solar and wind would cost us, the consumer, much more money. As little as you like coal plants, they perform a common good, in that they supply affordable, reliable electricity to the masses. AGW may change this, but this ongoing demonization of businesses that legally supply us with energy is somewhat shameful.’
    ——-
    Pointing out that Industry X causes air pollution is not demonizing it. It is just pointing out a verifiable scientific fact. Scientific facts are value neutral, by definition. Coal is a dirtier energy source than many other energy sources. That is a verifiable scientific fact. Simply stating that fact is not “demonizing” the coal industry. Facts are value neutral. The acid rain and mercury pollution in New England, which is severe in eastern Maine and Nova Scotia, is directly and provably due to emissions from coal plants in the mid-Atlantic corridor. This is a scientific fact. Scientific facts do not “demonize”. They don’t do anything. They just sit there and speak for themselves. As an aside, the coal industry has yet to offer a single penny of mitigation or compensation for the dozens of Atlantic salmon and brook trout rivers in Nova Scotia that are barren and biologically dead due to acid precipitation. This is a classic example of an externality that is not factored into the price of electricity derived from coal burning power plants. To have a scientifically responsible discussion of various energy sources, all externalities have to be included or else the analysis will be skewed from the very start. And energy efficiency must be given equal emphasis to energy sources. Energy efficiency is often left out of these type of discussions, which results in a flawed methodology and product from the outset. The economic and job benefits of energy efficiency technology alone warrant its equal consideration under any value analysis. Cheers.

  45. 145
    Phillip Shaw says:

    Re #139:

    Marco, you wrote: “Weather kills people, not climate. Scientists are on tenuous ground if they attribute deaths due to weather events on the climate changes. The causal relationship is difficult to demonstrate and impossible to “prove” scientifically. I will now assert that in a chaotic system (weather) the associated statistical averaging (climate or climate change) should not be attributed to either the frequency or severity of events in the chaotic system. I challenge the scientists on this forum to show causal evidence from the historical record to demonstrate this link suggested; or otherwise reject this statement by the WHO as unscientific.”

    That is the silliest thing I’ve read in months. You’re saying that during any of the historic ice ages, the increased snowfall (weather) that occurred can’t be attributed to the ice age (climate). Of course there is a causal relationship between the short-period chaotic phenomenon of weather and long-period climate. Can you even suggest any way in which they could be independent?

  46. 146
    Paul G says:

    ==== Comment # 141 by Tosh: ====
    “This appears to be a simplification of what is a cost and what is a common good. I am guessing that if the full lifecycle ‘costs’ and ‘common good’ of electricity sourced from coal power were fully accounted for and understood by consumers, consumers would be very happy to ‘pay the extra cost’ of solar and or wind power.”
    ====

    Consumers will be very displeased with greatly increased energy costs, even if it becomes necessary or mandatory. It is this resistance to higher costs by consumers that explains why little action has been taken so far. We are happy to support action against AGW in theory, but not so much in reality.

    ==== Comment # 142 by Dan: ====

    “Clearly some perspective on what is “shameful” is in order. DDT was “legally” applied on agriculture for many years with significant negative consequences on the ecosystem. Fortunately it was eventually regulated.”

    ====

    What is advocated in combatting AGW goes far, far beyond what occurred with DDT. Personally, I can not see any government in the world mandating reductions in CO2 emissions by 90%, can you?

    Regards,

  47. 147
    Doug Watts says:

    Animals are dying out because we’re eating their food.
    —-
    Not really. More correct attribution would be:

    a) Habitat destruction and modification over a significant portion of the species’ natural range.

    b) Over-harvesting (primarily ocean fish species)

    c) Causes A and B synergistically (great apes, smaller primates and large mammals, most acutely).

    d) Causes A and B along with toxic contaminant pollution, esp. DDT, PCBs, heavy metals. (especially large carnivores at top of food chain due to bioaccumulation)

    e) All of the above, and now increasingly in synergistic combination with climate change (polar bears, for one).

    Obviously, each and every species and population is affected by a differently weighted combination of the above general factors. Most disturbing and important is that species decline is severe right now and will continue to be so even if climate change were not happening and does not continue at present trends. Adding the synergistic impact of climate change onto the stresses which already exist could exponentially increase the risk of extinction, ie. by becoming the straw that breaks the camel’s back for species that might have otherwise made it through the bottleneck (sorry for the mixed metaphor). From direct experience in New England U.S.A. with Atlantic salmon, which are now close to extinction, you get to a point where there are just so few females left that the population loses all resiliency. Very small effective population size results in additional synergistic effects, particularly the harmful side effects of genetic bottlenecking and severe inbreeding among the few animals left. This is often called the extinction vortex. Many biologists believe the Right Whale, with only 300 or so animals left, are entering or have entered this vortex. Adding climate change to an already severely stressed and tiny remnant population could foreclose any hope of recovery even with massive, costly and elaborate long-term recovery efforts. So it’s extremely important, in my opinion, not to compartmentalize and consider in vacuo climate change impacts to animal/plant populations and ecosystems. That’s not how it works in real life. In real life, all of the various agents act at the same time in very complex ways, with numerous positive and negative feedback loops. Much like the weather.

  48. 148
    Tosh says:

    Re #146

    ‘Consumers will be very displeased with greatly increased energy costs, even if it becomes necessary or mandatory. It is this resistance to higher costs by consumers that explains why little action has been taken so far. We are happy to support action against AGW in theory, but not so much in reality.’

    Paul, if you read my statement again you will see that I think consumers need to understand the full costs/benefits of both sources of energy before we can make a ‘rational’ decision on price. I suggest that the reason people won’t pay a higher price is because they don’t understand the value represented by the price. For example, people pay more for a Britney Spears CD than they do for a local cover band copying Britney Spears because the difference is obvious.

    I don’t think enough people understand that although electricity is the same when it arrives at their house, it is produced in vastly different ways which affects its price.

    I suggest that the reason why limited action has been taken is because most people don’t fully understand the difference between clean and dirty electricity and that as a result of this, governments are not willing to take the political risk of increasing energy prices.

  49. 149
    Dan says:

    “What is advocated in combatting AGW goes far, far beyond what occurred with DDT. Personally, I can not see any government in the world mandating reductions in CO2 emissions by 90%, can you?”

    No, DDT applications were banned throughout the US so that “reduction” was far beyond what is being proposed for CO2 at this time. Safer DDT alternatives were found to mitigate the economic impact to farmers and environment impacts in general. Same can be said with sources of CO2. Who is advocating CO2 reductions that are far beyond what occurred with DDT? In fact, that would impossible considering DDT was banned here. Positive results (economic and environmental) were achieved when DDT was replaced. CO2 mitigation and emission reductions would be similarly beneficial. Goodness, no one is saying CO2 must be cut 90%.

  50. 150
    Paul G says:

    === Post # 148 by Dan: ===
    “Positive results (economic and environmental) were achieved when DDT was replaced. CO2 mitigation and emission reductions would be similarly beneficial. Goodness, no one is saying CO2 must be cut 90%.”

    ====

    A lot of people died when DDT was banned. It may have been fine (and affordable)to ban DDT here, but it was not in Africa.

    And C02 reduction would be massively more expensive then a simple ban on the use of DDT in North America. Our costs for energy would rise by an amount that millions would not be able to afford, without any observed benefit for decades. I don’t believe we are willing to pay that price as of yet.

    As for cutting CO2 emissions by 90%, George Monbiot advocates cuts of that magnitude; by 2030 no less!

    The Guardian Oct.31, 2006
    “Drastic action on climate change is needed now – and here’s the plan” – George Monbiot
    http://tinyurl.com/ylebvq

    Regards,


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