Charles Darwin was born on February 12, 1809. The events commemorating Darwin’s birthday anniversary last Sunday, together with the recent conclusion of an important court case concerning the teaching of Intelligent Design (ID) in public schools prompts me to some musing concerning the relation of the Evolution/ID dialog to similar issues arising in connection with anthropogenic global warming. The age of the two theories is similar as well: Darwin introduced his theory in 1859, whereas Fourier initiated the study of the effect of atmospheres on climate with his 1821 treatise, stimulating the chain of developments leading to Arrhenius’ enunciation in 1896 of the theory that human influences on the atmosphere’s CO2 content could change the climate.
I don’t propose to wade into questions of religion, or the question of whether or in what form ID could be taught in public schools. However, the discussion surrounding ID is significant because it has focused a lot of public attention on the question of : "What is science?" A Nov. 5, 2005 letter to the Chicago Tribune by one Mr. Ross Williams makes the connection explicit: In his letter, Mr Williams implies that the Theory of Global Warming is more like ID than it is like Evolution. Referring to global warming, he states: "It is no more than an idea, a notion." and goes on to say:
- " The scientists pursuing this hypothesis are struggling to test it and make predictions using their ideas. Thus far, they have had extremely limited success in testing, and virtually no luck in predicting–resulting in continually modified (and, consequently, less severe) forecasts. Despite this, they are spawning a whole cadre of non-scientific worry warts who are declaring that, well, really, the science doesn’t matter."
In Mr. Williams lexicon, a hypothesis is just "a notion," presumably not much better than ID. In this article, I will attempt to explain why the bleak picture painted by Mr. Williams and people of like mind is unwarranted.
Another relation between the two issues is that Evolution skeptics are motivated by ideology to deny a well-established scientific theory. In the case of Evolution, the ideological motivation is a perceived conflict between the picture of the operation of the natural world presented by the Theory of Evolution, and the tenets of certain faiths (a perceived conflict that, I am happy to see, is not shared by all people of faith, as witness the extensive "Evolution Sunday " activities ). Similarly, most Global Warming denialists are for the most part motivated not by abstract curiosity about the behavior of climate systems, but by a perceived conflict between the actions that would need to be taken to avert unacceptable climate change, and their beliefs about the extent to which economic growth and material prosperity based on fossil-fuel energy use should be unfettered. (Again, not all economists or members of the business community perceive a conflict here). In both cases, the skeptics prosecute not just an attack on the policy implications of science, but on the scientific method itself, often using similar rhetorical devices. In fact, sometimes skepticism about global warming and about evolution are combined in one and the same person, as is the case for Roy Spencer, for example (see his article on evolution here.)
Just what is the theory here?
First, we need to get straight on just what we might be talking about when referring to "The Theory of Global Warming." There’s a natural tendency to identify such a theory with the statement that "The Earth is Warming." That’s wrong because it confuses a theory with observations that might be used to test a theory. It’s also wrong because it would imply that the only reason we think that the Earth will continue warming in response to increased CO2 is that we already see it warming today; it loses the chain of physical causation. Somewhat better would be the statement, "The Earth is warming, and the warming is largely due to increases in atmospheric CO2 and other long lived greenhouse gases." This is defensible as a hypothesis, but I think it would be far better to consider this statement, too, as more properly in the domain of one of the tests we might apply to the Theory of Global Warming.
My own preferred statement of The Theory of Global Warming is this:
- An increase in the atmospheric concentration of CO2 and other long lived greenhouse gases requires the surface temperature to ultimately increase so as to maintain a balance with the absorbed solar radiation. The increase is amplified by water vapor (also a greenhouse gas), which increases with temperature in such a way as to keep relative humidity approximately constant. Melting of ice will further amplify the warming, particularly in high latitudes. The resulting widespread warming corresponding to a doubling of CO2 will be large enough and rapid enough to be well outside the range of past experience of the human species, by an amount comparable to the difference between a glacial and interglacial climate. Changes in atmospheric cloud properties may somewhat reduce or increase the sensitivity, but do not substantially alter the conclusion.
The last part of the statement of the theory is, of course, the hard part, and the most uncertain.
I have deliberately left the matter of the severity of the impacts of such a climate change out of the hypothesis. Theories regarding the impact are nascent and in many regards still rather ill-formed, in comparison to the theory dealing with the physical dimensions of climate change. Also, insofar as there are uncertainties about the severity of the impacts of climate change, it is a matter for the political apparatus to decide how to deal with the uncertainties, and the extent to which one should pay attention to the worst case vs. the most likely case. The question of how to factor in the uneven distribution of harms (and possibly benefits) across the peoples of the Earth, and between human societies and natural ecosystems, is also at heart a matter of ethics and values. These are questions that can be informed by science, but they are not themselves scientific questions.
Finally, one must be careful not to be confused by the usage of the word "theory" in common everyday English. Statements like, "Oh, that’s just a theory, not a fact" have little to do with the scientific understanding of the word "theory." Linguistic confusion goes the other direction as well: Scientists often talk about "believing" in a theory, but this expresses a judgement of whether the balance of tests of a theory against observations lends sufficient support to the theory to rely on it in drawing further inferences. It does not declare that subscribing to the theory or not is an article of faith, to be left to one’s conscience. If I say that I "believe in" quantum theory, that is expressing a different kind of judgement than if I say I "believe in" the tenets of Buddhism.
Judge Jones on "What is Science"
Judge Jones (a George W. Bush appointee, by the way) of the Middle District Court of Pennsylvania, presided over the case Kitzmiller v. Dover Area School District, which dealt with the constitutionality of an attempt to introduce some limited teaching of Intelligent Design into science classes. His decision that teaching ID in public school science classes would be an unconstitutional establishment of religion, is a masterpiece of wit, scholarship and clear thinking. Most of the decision deals with application of tests (such as the "Lemon Test") of whether a government action constitutes an establishment of religion. These make fascinating reading, and show Judge Jones’ wide ranging intellect, but they are not of concern to me here. What’s relevant to the point at hand is the rather extensive part of the decision devoted to the question "How do we know whether something is science?" This question wasn’t entirely central to the basis of the Judge’s decision, but he devoted a lot of attention to it because, in his words,
- "Having so concluded, we find it incumbent upon the Court to further address an additional issue raised by Plaintiffs, which is whether ID is science. To be sure, our answer to this question can likely be predicted based upon the foregoing analysis. While answering this question compels us to revisit evidence that is entirely complex, if not obtuse, after a six week trial that spanned twenty-one days and included countless hours of detailed expert witness presentations, the Court is confident that no other tribunal in the United States is in a better position than are we to traipse into this controversial area. Finally, we will offer our conclusion on whether ID is science not just because it is essential to our holding that an Establishment Clause violation has occurred in this case, but also in the hope that it may prevent the obvious waste of judicial and other resources which would be occasioned by a subsequent trial involving the precise question which is before us."
In other words, Judge Jones had already seen enough irreducible complexity, bacterial flagella, fossil record interpretations and panda’s thumbs to last a lifetime (maybe two), and didn’t want any of his colleagues to have to go through the same business all over again.
For the most part, the good judge takes a positivist approach to the definition of science, following Karl Popper. This approach emphasizes that a scientific theory should be falsifiable. The centrality of this notion has been challenged by Thomas Kuhn and a few other philosophers of science , but as a description of the way most of us in the trenches actually see our enterprise, Popper does pretty well, as long as we allow a little flexibility in the matter of what counts as falsifiability. The important thing is that a scientific theory should be productive. It should make predictions that can be tested against observation and experiment, the more the better. Thus, Ptolemy’s epicycle theory of planetary motion is not bad as a scientific theory: it does make predictions about where planets will be, that can be tested against data. Newton’s theory is far better, though, because it makes far more predictions over a vastly wider range of circumstances, while requiring far fewer assumptions. It’s not just that it’s more economical than epicycles. It’s far more productive of testable predictions — all of which prove true, so long as one steers clear of speeds close to that of light and very strong gravitational fields. Einstein’s General Theory of Relativity is even more productive, covering the extreme cases while reducing to Newton’s theory in the low speed and weak gravity limit.
Further, the notion of prediction has to be broadly construed. The fact that we can’t predict the exact weather a year out is no refutation of the basic theory of climate, any more than the fact that we can’t predict the position of Pluto in its chaotic orbit is a refutation of Newtonian mechanics. In the context of testing scientific theories, a prediction need not refer to something that happens in the future; this is important in observational sciences such as Earth science or cosmology, where one’s "predictions" often deal with things that happen in the past. A prediction in this context is any inference drawn on the basis of a theory, that can be objectively tested against observations. For that matter, a prediction need not even come in advance of an observation. Obviously, it is a more convincing test of a theory if the inference is made before the observation, since this provides some protection against the accusation of tuning unknown parameters; however, there are other ways to check whether a match succeeds only because of unwarranted tuning.
Judge Jones’ considers three basic arguments in his consideration of whether ID is science. The detailed application of each argument to ID is buttressed by numerous citations to theological, scientific and ID-advocacy writings, which are not reproduced in detail below.
The first argument is against ID as science is that science does not rely on untestable supernatural causes. Supernatural explanations are "science stoppers" which preclude further inquiry. This is, in essence, a restatement of the falsifiability (positivist) criterion. Among the many documents Judge Jones cites is a National Academy of Sciences statement that notes that the publications arguing for ID "do not offer hypotheses subject to change in light of new data, new interpretations, or demonstration of error. This contrasts with science, where any hypothesis or theory always remains subject to the possibility of rejection or modification in the light of new knowledge." The Judge declares, on the basis of the evidence, that "ID fails to meet the essential ground rules that limit science to testable, natural explanations."
The Judge notes that the preceding alone is sufficient to disqualify ID as science, but given a surfeit of evidence, he does not want to stop halfway. The next argument he produces is quite different from the positivism criterion, namely that the arguments for ID rest on a contrived dualism. "ID is at bottom premised upon a false dichotomy, namely, that to the extent evolutionary theory is discredited, ID is confirmed, " he writes. He then points out that arguments for ID based on this contrived dualism are, from a scientific standpoints, not arguments for ID at all, but merely tests of the Theory of Evolution — and hence only serve to further establish that Evolution is science. Judge Jones, in this connection, disassembles some of the arguments against Evolution made by ID proponents, but this is a matter of evaluating tests of Evolution as a scientific theory, not a matter of deciding whether ID is science. The notion of "irreducible complexity," for example, is a refutable and testable negative argument against evolution, but that does not make it a testable argument for ID. The discussion of the merit of ID proponents’ arguments against Evolution does, however turn up a point that has some relevence also to the argument brought to bear against the Theory of Global Warming. Discussing testimony on the ID case against Evolution, the judge writes: "We find that such evidence demonstrates that the ID argument is dependent upon setting a scientifically unreasonable burden of proof for the theory of evolution." (My emphasis added). The judge finds that Evolution skeptics argue by "pointing to real gaps in scientific knowledge, which indisputably exist in all scientific theories, but also by misrepresenting well-established scientific propositions." This description applies word-for-word to many skeptics’ arguments against global warming, for example to most of Richard Lindzen’s testimony to the House of Lords (discussed here)
Judge Jones’ third argument is a pragmatic one: it assumes that there is such a thing as a recognized scientific community, and that it knows science when it sees it even if it may be hard to rigorously and unambiguously define the criteria. He specifically looks to the peer-reviewed publication process as an indicator: "A final indicator of how ID has failed to demonstrate scientific warrant is the complete absence of peer-reviewed publications supporting the theory." After some further discussion of the publication record of ID, he concludes "ID is not science and cannot be adjudged a valid, accepted scientific theory as it has failed to publish in peer-reviewed journals, engage in research and testing, and gain acceptance in the scientific community."
Does "Global Warming Theory" pass Judge Jones’ science test?
In one sense, the Theory of Global Warming is clearly a falsifiable scientific theory: all we need to do is wait around a while until industrial activities have doubled CO2, and observe what has happened to atmospheric temperature, water vapor and clouds. This indeed seems to be the experiment that most of the world seems intent on carrying out.
However, when we talk about "verifying" the Theory of Global Warming, what most of us have in mind is doing something to test the theory right now, so that (to the extent that it is correct) necessary policy decisions can be informed by the predictions of the theory.
Earth science shares the full range of difficulties generic to observational sciences, in that we can carry out laboratory experiments testing individual basic physical principles making up our theories, but have only limited opportunities to conduct experiments on the collective behavior of the whole system. For the latter, we must do the best we can with those ready-made examples that Nature provides. In this regard, the situation of the Theory of Global Warming is rather similar to that of the Theory of Evolution.
There are indeed a great many aspects of the Theory of Global Warming that are falsifiable without waiting for the next century’s climate to come upon us. There are, to start, all the laboratory tests of basic physics, such as the infrared absorption properties of CO2 and water vapor. There are also field tests of the predictions of these basic physical theories, as is done when one measure water vapor and temperature in the atmosphere, and compares the predictions of radiative transfer theory with observed infrared radiation measured at the top of the atmosphere by satellite, or at the surface by radiation sensors. One can check the evaporation formulae used in climate models against the measured evaporation at buoys in the ocean, or the predictions of cloud models against observed cloud reflectivity. Going up the scale in complexity, one can compare the predictions of the theory against observations of recent climates, and of climates of the more distant past. General circulation models encapsulate the assumptions of the theory, and provide the tool necessary for testing hypotheses in such a complex system.
A further point regarding the positivist criterion is the the Theory of Global Warming is productive. The implied influence of CO2 (or methane) on climate can be, and has been, applied to the understanding of the Last Glacial Maximum, to Snowball Earth, to the Faint Young Sun, and to Cretaceous warmth. Variants apply also to Venus, Mars (present and past) and Titan. It is fair to say that this theory plays as central a role in the theory of planetary climate as the Theory of Evolution plays in biology. A relatied point is that the theory can be and has been challenged by data, and forced to adapt accordingly. This was the case in the precursor to the theory, when Tyndall discovered that minor constituents (CO2 and water vapor) dominated the greenhouse effect; the resulting adaptation of Fourier’s theory opened the way for Arrhenius to conclude that human influences on the atmosphere could change the climate. A more recent adaptation was the incorporation of aerosol effects in the late 1980’s which was forced upon the theory by the inability to explain the pattern of 20th century climate change with greenhouse gas increases alone. Contrary to the assertion in Mr. Williams’ letter to the Chicago Tribune, revisions to the theory have not led to any systematic downward revision of the appraisal of the magnitude of the thread caused by doubling CO2. Indeed, some discoveries, notably the prevalance of abrupt climate change in the past record, have raised concerns that the current understanding may underpredict the magnitude of the response.
What of Judge Jones’ other two criteria applied in the Kitzmiller case? The false duality issue does not arise in the judgement of Global Warming Theory itself, since the theory has never been argued for on the basis of such a stipulated duality ("The world is warming, and if it’s not the Sun, then it must be CO2!"). On the other hand, a false duality has often been invoked in arguing against the Global Warming Theory. This typically takes the form of pointing out some aspect of the observations that Global Warming Theory doesn’t explain, and then jumping to the conclusion that the observed warming must be due to the local skeptic’s favorite cause: maybe solar variability, maybe some unspecified sort of "natural variability." Often such arguments involve holding Global Warming up to unreasonable standards of proof ("If we don’t understand everything about climate, then we understand nothing about climate."), and often, like ID proponents arguing against Evolution, the arguments offered against Global Warming are at best distortions of scientific truth. In this regard, Global Warming plays the role of the Theory of Evolution, with the Global Warming Skeptics playing the role of ID advocates.
On Judge Jones’ final criterion (presence in the peer-reviewed literature) the Theory of Global Warming gets an easy and obvious pass. Here, the Global Warming skeptics are in a somewhat better position than the ID advocates, in that a very few of the skeptics arguments have appeared in the peer reviewed literature. This doesn’t make them right, but it does mean that to some extent, some of them are playing by the rules of science. Still, the relative paucity of skeptics arguments being played out in the peer reviewed literature suggests that they may not be as wrong as the ID advocates, but that they are not as right as the vastly greater number of researchers who have published in support of the Global Warming Theory.
To what extent is "Global Warming Theory" verified?
The basic physical principles upon which the Theory of Global Warming is based include the notion of interconvertibility amongst forms of energy (introduced by Fourier in his formulation of planetary energy balance), thermodynamics (air cools when it rises), thermodynamics of phase change (cold air holds less water), quantum theory (absorption and emission of infrared by CO2 and other greenhouse gases), blackbody radiation, and Newton’s laws of motion. Each of these components has passed literally thousands of tests in the laboratory. There is essentially zero uncertainty in the validity of such things, which form the basic physical underpinning of the Theory of Global Warming. If any of these parts of the theory didn’t work, neither would microwave ovens, computers, steam engines, infrared remote controls, and any number of other everyday devices.
Tests of the collective behavior of the Earth’s climate system are somewhat harder to come by, but there has been substantial progress here as well. I would highlight the following, which is far from an exhaustive list:
- Reproduction of the temporal and spatial pattern of 20th and 21st century warming. To be sure, models with varying assumptions about clouds and aerosols can fit the observed warming equally well, indicating that the job is not complete. However, no quantitative model based on physical principles can match the 20th century warming without incorporation of a substantial warming component from greenhouse gas increases.
- The rapid increase in atmospheric greenhouse gases should throw the Earth’s radiation budget out of balance, because the ocean has not yet had time to warm up to restore balance. The expected imbalance has been observed. (Hansen et al. 2005)
- The planet’s energy imbalance has implications for the pattern of subsurface ocean warming. The predicted pattern has been observed. (Discussed here.)
- Satellite observations indicate that mid-tropospheric water vapor is indeed increasing with temperature, as the theory requires and as models predict (Discussed here).. Note that the water vapor assumption I included as part of the statement of the Theory of Global Warming is not itself built into the general circulation models used to predict climate change. It is an emergent property that is deduced from more basic assumptions made in the models. In this regard, the statement regarding the presumed behavior of water vapor amounts to a statement that the models capture the same processes governing water vapor in the real atmosphere. There is now a wealth of evidence (in the "large scale control" literature) supporting this viewpoint.
- Melt-back of Northern Hemisphere sea ice
- Nearly worldwide melting of mountain glaciers, many of which survived previous naturally occurring warm periods
- The theory predicts that the stratosphere should be cooling at the same time the surface is warming. This pattern is observed.
- The degree of cooling of the Tropics and Southern Hemisphere during the Last Glacial Maximum, for which there would be no explanation if we were to assume that current models substantially overestimate sensitivity to CO2. An interesting bit of history concerning this point is that in the 1980’s the tropical behavior in glacial times was considered an indication that models were wrong: CLIMAP data indicated little surface cooling in the tropics, while mountain snowlined data did show cooling. This led to all sorts of theories spun about exotic thermostat mechanisms and strange lapse rate behavior. In the end, it turned out that the models were right and that the CLIMAP data was wrong. Thus, in this instance, the models (based on theory) made a true prediction, which was verified after the fact.
The scientific community is still searching for a really good way to evaluate the nature of cloud effects, though comparisons with past and recent climates provide some reassurance that we are not too far off base with cloud effects. More importantly, there is not yet a physically based hypothesis on the table which is compatible with data and which reduces climate insensitivity to inconsequential levels. Lindzen’s "Iris" hypothesis comes closest, but it has been evaluated in the scientific literature and most of the community remains unconvinced.
Besides the ongoing problem with clouds, the general theory of Earth’s climate, like any good scientific theory, continues to be confronted by phenomena it cannot yet fully explain, and to evolve in response. Some notable problems include the tendency of many coupled general circulation models to produce double Intertropical Convergence Zones in the Tropics, inconsistencies in the prediction of the regional distribution of climate change, inability to make firm inferences concerning the effect of global warming on El Nino, and the inability of general circulation models to reproduce recurrent abrupt climate change events like D-O events or even the full magnitude of response to the Younger-Dryas event. An especially notable unresolved challenge is the inability of models to reproduce the low North-South gradient in warm climates such as the Cretaceous. In this case as well as in others (such as the problem of vertical structure of tropical tropospheric warming) the problem may lie as much in the data sets being used to test the theories as in the theories themselves.
A theory can never be definitively proved; there is always the possibility that some new observation will overturn it, and most theories are imperfect and fail in one way or another to account for some of the data. The question thus emerges as to the extent to which global warming skeptics are holding the theory up to an "unreasonable standard of proof," much as ID proponents do in the case of Evolution. Given that the intensity of interest in the Theory of Global Warming stems largely from its policy implications, it is fair to ask how the standards of proof to which global warming has been held stack up against other theories that have been used to make policy decisions of enormous consequence. "Supply Side Economics" (the theory that tax cuts pay for themselves by stimulating economic growth) is a telling example that comes to mind (to say nothing of the "theory" that Iraq had WMD).
Afterword
And speaking of intelligent design, I feel compelled to remark that the CO2 molecule seems rather admirably designed from the standpoint of regulating climate. It’s a good infrared absorber even in small quantities so you don’t need to much of it, yet the radiative effect is logarithmic in concentration, so you don’t have to tune its concentration too terribly precisely to get a habitable climate. There’s plenty of it in the form of carbonates in the Earth’s crust, so you can always get more if you need some to keep the climate warm enough. Most importantly, it plays well with liquid water, so that if the planet gets too warm or too cold the rate of removal tends to adjust to reset the atmospheric carbon dioxide at a point where the climate will stay relatively equable. It has thermodynamic properties that keep it from condensing out of the atmosphere (in contrast to water vapor), resulting in it having a long enough lifetime to even out the vicissitudes of climate forcing fluctuations. How strange it is, then, that the Earth should have an abundant supply of so attractive and convenient fuel as coal. A fuel which, unfortunately, messes up the system by releasing CO2 when it is burned.
Bad design? Or just forbidden fruit?
References
Hansen, J., et al. 2005. Earth’s energy imbalance: Confirmation and implications. Science 308, 1431-1435, doi:10.1126/science.1110252.
This just hit the wires:
click here
The Greenland numbers for glacial melt and calving were off by a factor of two. Twice as much.
In reference to climate change impacts you write: “It is a matter for the political apparatus to decide how to deal with the uncertainties, and the extent to which one should pay attention to the worst case vs. the most likely case.”
[Response: A fair enough point. I focused on the worst vs. the most likely case because most economic analysis and indeed most policy analysis tends to gravitate toward the mid-range of the predictions. I loosely called this the “most likely” case, though I don’t actually believe we have any sensible way to assign probabilities to the different forecasts. We know what is possible, but not really what is likely. Judge Posner, in his book on Catastrophe, make an argument for paying the most attention to extreme cases with very severe consequences, even if their probability is small or poorly quantified. His book advocates this for global warming in particular, as well as a number of other potential catastrophes. –raypierre]
Shouldn’t that last phrase be “worst case vs. best case” or “least likely case vs. most likely case”? I have never understood why outcomes that are somewhere between the worst case and the best case seem automatically considered to be “more likely” than the extremes. Does anyone really have any basis for judging which climate change outcomes are ultimately more or less likely?
Certainly, all the empirically observed effects of climate change that I’ve seen reported in the mainstream media (more often in the British and European media than the US media, of course) over the last year or so are consistent with worst-case, or at least worse-case, scenarios, ie. multiple tipping points and self-reinforcing feedback mechanisms driving irreversible runaway warming leading to global, ecologically catastrophic climate change in the not-too-distant future. Based on those reports, it increasingly seems to me that the worst case is the most likely case.
Happy birthday to the Kyoto Protocol, too (February 16, 2005).
Very nice thoughtful article. Science is infinitely fascinating – the celebrating the birth of a man almost 200 years ago, a towering genius, who’s work still causes such contention (I think he would be amused), and linking him to a discussion of the arguments around global warming, is the sort of thing James Burke used to do in “Connections” in Scientific American, though your article is much better and a great deal more informative. I am reading this in New Zealand, a country that has just reneged on its commitment to a carbon tax, on a day when new information about melting Greenland glaciers is that it is double the previously suspected rate, and where today a meeting between government officials and all of New Zealand’s forestry owners – in regard to global warming, carbon credits and future policy – broke up in acrimony, with no common ground. Have you every thought of a similar discussion in regard to the oft-quoted experiment of frogs being heated up in a large saucepan?
Your rhetorical question about coal is interesting. I have often wondered myself, when I am pretending to be an amateur James Lovelock, whether the coal seams, and oil and gas deposits for that matter, are themselves not part of the Earth-Life interaction in our planetary geostasis. In other words, when global warming sceptics pooh-pooh global warming, and say that the Earth must have always had many different protective mechanisms in the past to preserve an equable climate, would it be reasonable for me to say, yes, but one of those mechanisms was coal and gas deposition. That we are in effect, in the space of a couple of hundred years, re-introducing into our atmsophere the combined effects of 200 million year’s worth of global carbon sequestration? In that sense it is not at all strange we should have an abundant natural resource of carbon. What the Earth (Gaia) didn’t really count on was having a species come along that would have precisely enough intelligence to make use of it, but sufficiently lack the intelligence to do so wisely. Now that is strange.
[Response:What I pointed out once in an essay I wrote elsewhere is that humans are a little like burrowing worms writ large, so far as our access to fossil fuels goes. When metazoans (animals) evolved, they changed ocean chemistry by greatly increasing the portion of the sediments that interacts with the ocean — to the tune of several centimeters. No inanimate process or non-human animal can release the sequestered fossil fuel organic carbon at a rate anything like what we are able to do. So, insofar as we’re part of nature, we’re not so different from other biological effects. It’s just that we have a much bigger footprint, and that we can (en principe) forsee the consequences of what we are doing. –raypierre]
Excellent post with a very nice summary of the Kitzmiller decision and a sensible discussion of the relevant philosophy of science. A corollary is that the ID folks can get traction only by attempting to change the evidentiary ground rules to assume the explanatory power of supernatural entities, as Michael Behe had to concede in his pitiable testimony. Having been defeated in the chess game, they are trying to upset the board. Similarly, the ‘climate skeptics’ have to resort to rhetorical tricks and sometimes outright dishonesty to make their case. Failure to make honest arguments is a de facto concession of defeat.
A really excellent piece (great to see the appreciation of the Judge Jones opinion). The afterword and comment no 4 touch – maybe playfully – on Lovelockian type ideas of self regulation. Given the mauling Lovelock received in a recent post on this site, do the authors think that argument is closed?
(In a 16 Jan 06 article Lovelock made his own homage to Darwin: “Had it been known then that life and the environment are closely coupled, Darwin would have seen that evolution involved not just the organisms, but the whole planetary surface”)
You test of global warming theory by letting man continue his “industrial activities”, opens others to assume you mean only his industrial activities, and nothing else man does.
So, skeptics will try the reverse thought experiment, and assume we removed all of man’s “industrial activities”, also ignoring the concomitant activities what do we get?
The Woods Hole Research center puts the missing carbon sink at 46% of our emissions (this seems high to me). But, all things being equal, that sink puts us in glaciation in 250 years.
And this is exactly the argument that skeptics are making.
[Response: Why would that put us into glaciation? If emissions drop to zero, so does 46% of our emissions – William]
To Doug Percival-
I see that raypierre has already replied, but I think there’s an important clarification to make: considering the worst case vs the most likely case is the act of choosing a defined level of acceptable risk.
In all but the most forgiving circumstances, it makes practical sense to assume that something a bit worse than likely will be a very possible outcome, and thus it’s a good idea to make allowances, plan for a non-optimal and perhaps unexpected case. Of course that’s paralyzing if taken too far, but if not taken far enough the consequences may be equally devastating.
“Worst case vs probable case” is also a better idea than “worst case vs best case” and “probable vs improbable” because it creates a multidimensional picture of the choice. “Worst vs best” imagines, as you point out, that these are located at opposing points on some probability gradient. “Probable vs improbable” makes the same mistake concerning desirable and undesirable outcomes. What we actually want is a reckoning between the cost of absolute failure and the quality of our best guess about how well we understand the system in question.
That is exactly the function of a political apparatus, and it’s a function that is generally not being performed in the United States. There is no collection of people more in need of a firm scientific rigor and comprehension anywhere in the world. These people make choices for a living – they should be able to evaluate data and methodology.
In light of the obs on the acceleration of Greenland’s ice sheet a post on this subject would be most welcome. In particular the question of whether current ice-sheet models do an adequate job of representing the effect of meltwater on lubricating the flow of the glaciers seems to be important regarding the speed with which the Greenland ice sheet might melt/disappear.
[Response:A glaciologist may disagree, but as far as I know, they do not. Single mountain glaciers are reasonably modelled, but that is somewhat easier than, but quite different to, the main ice sheets. This obviously adds significantly to the uncertainty in the ice sheet response. -gavin]
Darwin’s detractors always got published not so with climate skeptics
[Response: Actually, when skeptics make any semblance at all at playing by the rules of science, they have no trouble getting published. Many of the skeptics arguments are allowed through peer review even though the reviewers know they are flawed, because it is thought better to let them be discussed and shot down out in the open. I’ve done this myself from time to time, notably with Lindzen’s Iris paper, on which I was a (non-anonymous) reviewer. If there aren’t many skeptics’ papers in the literature, it’s because most of them don’t or can’t play by the rules of science. ]
Re the response to my comment by WIlliam:
[Response: Why would that put us into glaciation? If emissions drop to zero, so does 46% of our emissions – William]
I am not quite sure what you are saying, as a layman, which is kind of the point I was making.
The layman assumes all things are equal, and if we remove our emissions, the carbon flux is still there, and the sink still takes natural carbon from the atmosphere.
What we fail to tell the layman is that man’s impact on the carbon budget is more complex, and a lot of man induced carbon fluxes are tied to the oil economy outside of emissions. Oil makes clear cutting in China easier, but oil also allowed us to abandon much of our inefficient agriculture and let the land return to natural forest.
Folks who understand the Kyoto protocols understand man made sinks and sources, the layman only hears the emissions part.
[Response: Umm, OK, I didnt understand you. Still not perfectly sure I do. To be clear: there is a CO2 record from ice cores for the holocene – last 10kyr say – which is stable at about 280 ppmv. So the default is stability, in the absence of people (on timescales shorter than ice ages…). Since we’ve increased the atmos conc, its not too surprising that there is a net sink, removing some (about half, as you note) of that. But it would be odd if that increased sink didn’t come back into balance if CO2 levels declined. See-also David Archers post on the long-term future of CO2 levels – William]
You mention the opposition to global warming theory by (some) opponents of evolution. I’ve always wondered about this. I think it has to do with several factors. First, if one believes that the world is shortly coming to an end, as some religious fundamentalists do, then it doesn’t make much sense to worry about what we are doing to the global environment. I believe that James Watt, Reagan’s first Secretary of the Interior, stated this position explicitly. Second, it is important to remember that some of the evidence that climate scientists use is based on paleoclimate studies. If you believe the world is 6,000 years old, you are not going to pay attention to conclusions based on ice cores detailing a history of more than one hundred thousand years. Finally, I think some of the opposition results from a gut reaction against what such people feel are elitist atheisitic scientists who they feel oppose their whole way of life. For the same reason, many such people feel comfortable aligning themselves, contrary to their own economic interests, with free market conservatives. Of course, just as many evolutionary biologists are believing Christians, I am sure many climate scientists are politically conservative in other matters. (James Hansen, by report, liked John MCCain, who is quite conservative on most issues.) But the perception is that you are all Greenpeace activists.
The latest move by some evangelicals to support measures to deal with global warming is a good sign. These people see man as entrusted with God’s creation and believe we are not doing a good job in that regard. But these people may not be fundamentalists, so I’m not sure what that means.
Re 10
I’m sure Lindzen, McIntyre and McKitrick, Baliunas & Soon, Michaels, and others will be incensed to learn that their publications don’t count. Or are they not skeptics? M&M even point out with ill-concealed glee the rejection of their detractors’ papers. Perhaps you could bolster your argument with a few examples of worthy skeptical papers that have been suppressed. In any case, most of Darwin’s detractors published from the pulpit, not the peer reviewed literature, to the extent that there was one at the time. Skeptics seem to have no trouble getting published in today’s analog – conservative think tanks and media.
Wonderful post, but I think you’re relying way too heavily on Popper, and that Jones *isn’t*:
http://scienceblogs.com/intersection/2006/02/evolution_climate_change_and_t.php
[Response: It’s interesting that Judge Jones didn’t rely just on the positivist argument, but nonetheless he did put it first and returned to it at several junctures. I’d like to call this “neo-positivism,” since Popper’s original work had an overly optimistic view of the extent to which interpretation of observations could be separated from theory. Popper’s not perfect, but attempts to do better haven’t been as workable, in my view. Kuhn fails because not much of science is like the examples he quotes. For that matter, even the “revolutions” he quotes are more incremental and build more on past work than his simplistic picture admits. For example, Planck’s work on quantum theory still made use of the basic mechanisms of statistical thermo developed for the classical case. Worse, when you follow Kuhn to its conclusions you get nonsense like science as social construction, and we know what kind of absurdity that can lead to (anybody remember l’affair Sokal?). Quine tried to be more precise than Popper, but under Quine’s picture, it’s hard to see that even Physics is science. So, unless some professional philosopher of science sets me straight, I’m stuck with some kind of Popper-lite as the description of science that resonates most with the way those of us doing it see the subject. –raypierre]
Regarding #9: Thank you for the excellent detailed review of the judges notes. Darwin did have a chance to observe glaciers and has a surprising number named for him, a worthy acknowledgement indeed.
With respect to ice sheets, as a glaciologist in fact our models generally work better because there are fewer small scale important boundary conditions changes on an ice sheet than on a mountain glacier, it is a simpler system in general.
Bi-polar accleration:
A bi-polar acceleration of key ice sheet outlet glaciers has been observed in the last decade. Pine Island and Thwaites Glacier West Antarctic Ice Sheet (WAIS) and Helheim, Kangerdlugssuaq and Jakobshavns Glacier in Greenland have all accelerated dramatically. Twenty years ago Terry Hughes proposed the Jakobshavns Effect (JE). The JE as explained by Hughes (1986) results from an imbalance of horizontal hydrostatic forces at the grounding line. With positive feedback mechanisms that sustain rapid ice discharge: ubiquitous surface crevassing, high summer rates of surface melting, extending creep flow, progressive basal uncoupling, lateral uncoupling, and rapid iceberg calving.
Are the recent outlet glacier accelerations indicative of the Jakobshavns Effect at work via the reduction in back stress allowing the ice to be pulled out of the ice sheets, or is reduced basal coupling solely enhancing basal sliding? This can be answered but is off topic of this post.
I found this on a seb site that I periodically visit.
Plant enzyme efficiency may hold key to global warming
Global warming just may have met its match. In research recently completed at Emory University School of Medicine, scientists have discovered a mutant enzyme that could enable plants to use and convert carbon dioxide more quickly, effectively taking more of that gas out of the atmosphere.
The findings were published online on January 19 and will appear in the February issue of the journal Protein Engineering Design and Selection. Ichiro Matsumura, PhD, assistant professor of biochemistry at Emory University School of Medicine, is the senior author and principal investigator. The lead author is research specialist Monal R. Parikh.
During photosynthesis, plants and some bacteria convert sunlight and carbon dioxide into usable chemical energy. Scientists have long known that this process relies on the enzyme rubulose 1,5-bisphosphate carboxylase/oxygenase, also called RuBisCO. While RuBisCO is the most abundant enzyme in the world, it is also one of the least efficient. As Dr. Matsu-mura says, “All life pretty much depends on the function on this enzyme. It actually has had billions of years to improve, but remains about a thousand times slower than most other enzymes. Plants have to make tons of it just to stay alive.”
RuBisCO’s inefficiency limits plant growth and stops organisms from using and assimilating all the carbon dioxide in the atmosphere, even as the amount of gas in the atmosphere con-tinues to grow. The resulting gas buildup is one cause of global warming. A 2004 report by the National Science Foundation estimates that atmospheric carbon dioxide concentrations remained steady at between 200 and 280 parts per million for thousands of years, but that carbon dioxide levels have risen dramatically since the Industrial Revolution of the 1800s, leading to 380 parts per million of carbon dioxide in the atmosphere today.
For decades, scientists have struggled to engineer a variant of the enzyme that would more quickly convert carbon dioxide. Their attempts primarily focused on mutating specific amino acids within RuBisCO, and then seeing if the change affected carbon dioxide conver-sion. Because of RuBisCO’s structural complexity, the mutations did not have the desired outcome.
For their own study, Dr. Matsumura and his colleagues decided to use a process called “directed evolution” which involved isolating and randomly mutating genes, and then inserting the mutated genes into bacteria (in this case Escherichia coli, or E. coli). They then screened the resulting mutant proteins for the fastest and most efficient enzymes. “We decided to do what nature does, but at a much faster pace.” Dr. Matsumura says. “Essentially we’re using evolution as a tool to engineer the protein.”
Because E. coli does not normally participate in photosynthesis or carbon dioxide conversion, it does not usually carry the RuBisCO enzyme. In this study, Matsumura’s team added the genes encoding RuBisCO and a helper enzyme to E. coli, enabling it to change carbon dioxide into consumable energy. The scientists withheld other nutrients from this genetically modified organism so that it would need RuBisCO and carbon dioxide to survive under these stringent conditions.
They then randomly mutated the RuBisCO gene, and added these mutant genes to the modified E. coli. The fastest growing strains carried mutated RuBisCO genes that produced a larger quantity of the enzyme, leading to faster assimilation of carbon dioxide gas. “These mutations caused a 500 percent increase in RuBisCO expression” Dr. Matsumura says. “We are excited because such large changes could potentially lead to faster plant growth. This results also suggests that the en-zyme is evolving in our laboratory in the same way that it did in nature.”
Even as these results are published, Matsumura and his team are continuing their research on the RuBisCO enzyme. To start, they’ll experiment with increasing mutation rates on genes during di-rected evolution and look for undiscovered connections between the enzyme’s structure and function. Perhaps, with a little more evolution, RuBisCO might be able to shed its ignominious reputation as the slowest of plant enzymes.
[Response: I don’t see this as much of a solution to global warming. After the plants take up all that CO2, what are you going to do with the plant biomass? Unless you keep it from rotting, it’s going right back into the atmosphere. –raypierre]
Thanks for the well written post, though I must confess that I am fairly disappointed that it was posted on this site. I have enjoyed being able to point skeptical friends here for a dispassionate look at global warming news and analysis. Despite how well written this is, it will largely serve to reinforce the views of those of us who already agree with the science in both of these areas. I know exactly how a few of my friends who adamantly reject darwinism would react.
I fear however, that it will likewise reinforce the skepticism of those who might at least be willing to reconsider their opposition to GW science, but not willing to reconsider a tightly held religious view about the origins or development of life.
It is of course all part of an important scientific dialogue, but I (and who am I to push my views here) view this site as specifically targeted to the very important issue of global warming.
That said, thank you so much for your very important work here!
[Response: I understand your concern, and indeed the last thing I’d want to do would be to turn people away from considering the scientific case supporting global warming just because they see it as wrapped up in the same epistemological world that supports the theory of evolution. That said, I don’t see how I could reconcile different standards of evaluation of scientific theories being applied to evolution vs. global warming. I suppose that Young Earth Creationists that believe in physics enough to fly in airplanes have found some way to make the accomodation, and may be able to apply the same accomodation to global warming physics, but I myself don’t understand how that is done. –raypierre]
Brilliant intellectual analysis that must have taken a lot of time and research. This is a very useful synthesis of thoughts I have been having, but have never yet been able to put on paper. Thank You.
The whole planet is a recycling bin. That’s the point that needs to be driven home with the out of sight out of mind crowd. Nothing really leaves, it just moves somewhere else.
Re: #16 Any ideas how to make coal?
Ref: #15
Thank you. I visited your site and finally got my answers as to the mechanism for glacier retreat. The chart showing the number of retreating versus advancing glaciers in various locations around the globe is very convincing. There has to be a commonality such as well-mixed greenhouse gases.
I love data and consider models as mere tools, not oracles. As a humorous aside, I respect Jim Hansen but felt that he hung out with models so long that he became one of them. Now I find he has become a data grinch too with the statement, “None of the current climate and ice models predict this. (the speed of the Greenland retreat) But I prefer the evidence from the earth’s history and my own eyes.” Right on, Jim!
Mark York has it, the recycling bin.
The uraniam analogy is working for me.
Climatologist say,”Nature has buried carbon deep and stabilized the climate. Now man is digging it back out”
RE: “I don’t see this as much of a solution to global warming.”
Are you perhaps missing the point? What are the implications, if this particular science proves out, vis a vis carbon fixing mechanisms and our understanding of the carbon fixing behavior of the biosphere, en masse?
> ideas on how to make coal
Isn’t the standard way looking likely? Just run temperature and CO2 up a ways to a steamy-swamp world for, um, a while, and bingo, coal beds!
Bravo! A wonderful article!! But, as I posted previously, most scientists are atheists (as am I):
http://kspark.kaist.ac.kr/Jesus/Intelligence%20&%20religion.htm
http://pancake.uchicago.edu/~carroll/nd-paper.html
Yes, this is not a web site about religion, but the way that most scientists see the world is fundamentally different than the way most laypeople (a category that I fall into) see it! This is why global warming (and evolution) is ubiquitously accepted within the scientific community but not by the general public.
[Response: I don’t know whether it’s actually true or not that most scientists are atheists. It could be hard to know for sure, since people are rather private about their religious feelings, perhaps scientists more so than most. The answer you get would also depend a lot on how you phrase the question. That is somewhat beside the point, though. There is ample evidence that there is no intrinsic conflict between religion, per se, and the use of the scientific method as a way of understanding the natural world. Religion and science answer different kinds of questions, and use different methods. In many cases, this statement is official doctrine, as it is (loosely speaking) for the Catholic Church. The important thing is to keep those two aspects of human’s attempt to make sense of the Universe in their proper spheres. To not do so is not only bad science, but ultimately bad theology. To be sure, it’s not hard to find types of religious faith that are flatly incompatible with inferences drawn from science, but my point is that such a conflict is not intrinsic to religion itself. A person whose faith requires them to reject science altogether would be perfectly justified in doing so, but it would be wrong to muddle the issue by trying to justify such an action by scientific means. There are deep theological questions here, but I’ve probably already come too close to the line of what’s appropriate to discuss on RealClimate. –raypierre]
Re 16 (and the reply):
An obvious use for a plant that efficiently sucks carbon out of the atmosphere is to produce biofuels. This would not change the current level of CO2, but might allow us to stop burning fossil fuels without changing our energy budget. Another use for such an advance would be the production of a best-selling science fiction novel about an engineered plant going native, evolving into a weed that crowds out all other plants, and threatens to plunge the earth into a deep ice age by removing all of the carbon from the atmosphere. If only there were a science fiction writer who could ignore and distort real science enough to make such a scenario plausible to a gullible public!
[Response: An interesting set of possibilities. To amplify on my reply to #16, one mustn’t confuse biological productivity with carbon sequestration. If you increase the rate of CO2 uptake and then somehow keep the biomass from oxidizing (setting it on the long route to becoming coal or oil) then you will indeed offset fossil fuel emissions. It would be an admirable type of recycling. The tricky thing is to do the sequestration part. Now, Molnar’s comment raises an interesting alternate possibility — to use the increased CO2 uptake to make biofuels more efficiently. To the extent that these replace fossil fuels, that also works. With regard to the specific point in 16, though, the question here is whether CO2 utilization is the limiting factor in the conversion of sunlight to energy stored as chemical bonds in the plant’s mass. If not, then the proposal wouldn’t help much in increasing the efficiency of biofuel production. ]
I must say that this post is quite the best I’ve read on this subject. It should be posted in schools across the country. Also, I must say that the hyperlinks are excellent. Indeed this is true throughout “Real Climate”. Absolutely first class!
I suppose you could call me a skeptic, a contrarian, a dissenter – or more pointed names. But when the IPCC First Italian Report was doctored to remove dissent, doubts were instilled.
Various other incidents have led me to doubt the IPCC certainties. Not necessarily the science, but the overt political thrust of the organization.
I was unable to determine any uncertainty in the IPCC website. The EPA at one time had a page of uncertainties, but then it disappeared. Apparently, under the influence of the present Administration it has moved back – not to genuine scientific uncertainties – but to politically inspired doubts.
[Response:I don’t understand quite how you failed to find any uncertainy. The TAR SPM sayeth “Over the 20th century the increase has been 0.6 ± 0.2°C” – this is an expression of uncertainty. Or try fig 5. Or… well, I just don’t see how you can have missed it – William]
Scientists are people too. The money and perks available to IPCC people are extensive. If oil company scientists are unenthusiastic about GW, then it can be argued that IPCC scientists might be enthusiastic from the same kind of incentives.
[Response: The idea that there are vast wealth and perks to be made from climate science is wrong, and would raise a laugh (albeit a rather bitter one) from anyone “inside” – William]
[Response: Money and perks! Hahahaha. How in the world did I miss out on those when I was a lead author for the Third Assessment report? Working on IPCC is a major drain on ones’ time, and probably detracts from getting out papers that would help to get grants (not that we make money off of grants either, since those of us at national labs and universities are not paid salary out of grants for the most part.) We do it because it’s work that has to be done. It’s grueling and demanding, and not that much fun, and I can assure everybody that there is no remuneration involved. The only thing that might seem like a “perk” to those outside the process would be the international travel (about four trips per report), but these trips are anything but fun. Most of us have more opportunities than we need for international travel, research conferences like the Ascona one on Neoproterozoic climate are much more fun than IPCC, and anyway given all the necessary travel, most of us would rather have more time to spend at home with our families. When I went to New Zealand with IPCC, I spent all my time locked up in the hotel writing reports and having discussions with our chapter authors, then had to head right back to cover my teaching (and to make matters worse got stuck overnight in Los Angeles because of a Chicago snowstorm, missing a fantastic performance of Carmen by the Lyric Opera, for which I had subscription tickets). IPCC is important work, but it’s not something one would wish on one’s best friends. I’m very happy you liked the Darwin article, though. –raypierre]
I suspect that much of the problem may rest in Working Group Three – the “social science” part of the operation – and therefore not subject to the rigor of natural science.
I bet the “uncertainty” memo recently published by the IPCC (it was very good) doesn’t apply to WG3 whose job may be to inform and perhaps frighten the great unwashed.
So my view of GW is that it may well be true in all its aspects, but it is difficult to be sure of anything when a government funded political juggernaut is carrying the ball of absolute certainty. (How I mix my metaphors!)
I should be clear that Real Climate is just about the best information source on GW I have found – even though you seem to bring up contrary opinions only to knock them down. However, I regard that as perfectly fair – and the hyperlinks are so good!
Thanks for this excellent paper. Its description of the big picture of Global Warming and how it fits in with the philosophy of science is clear and concise.
The judge’s second argument, scientifically unreasonable burden of proof, is indeed the error behind most Global Warming skepticism. I have been there and it took years of more observations and the failure of better explanations to appear to “convert” me. I had no hidden agenda; I was looking for “truth”.
There is nothing new about qualified scientists looking at the same data and arriving at different conclusions. There is also nothing new about the most outspoken ones going down in flames rather than admitting that they are wrong. What is the likelihood of Gavin becoming a “denier” and Lindzen becoming an “alarmist”…. zero and never.
What is a problem is not so much the subtle name-calling like alarmist and denier, even Bohrs and Einstein did that, but rather the questioning of motivation. No one knows what is in the other person’s mind. To imply that what is there is negative leads to resentment. Resentment means confrontation and inaction. It is much better to assume that the other person comes from the same place as you. When publically visible climate scientists agree on something, then maybe progress on this issue will be made. I wonder if a peace conference attended by Hansen, Schneider, Michaels and Lindzen would work.
Re #27
I don’t understand where this conclusion could have possibly come from: “I was unable to determine any uncertainty in the IPCC website” Not only is practically every conclusion in there specific in mentioning uncertainty, the phrases used to describe levels of certainty are formally defined.
Also, you might be interested in the position statement issued by the Australian Academy of Sciences, Royal Flemish Academy of Belgium for Sciences and the Arts, Brazilian Academy of Sciences, Royal Society of Canada, Caribbean Academy of Sciences, Chinese Academy of Sciences, French Academy of Sciences, German Academy of Natural Scientists Leopoldina, Indian National Science Academy, Indonesian Academy of Sciences, Royal Irish Academy, Accademia Nazionale dei Lincei (Italy), Academy of Sciences Malaysia, Academy Council of the Royal Society of New Zealand, Royal Swedish Academy of Sciences, and Royal Society (UK).
You can read at the URL below their position on the soundness of the science presented by the IPCC. If it were politically skewed, these organizations would not endorse it.
http://www.royalsociety.org/displaypagedoc.asp?id=13619
Speaking of sequestering — Has anyone tried (modeled) piping oxygen down and burning methane from ice at depth and pressure? The exhaust pressure would be, um, greater, but the cooling would be great, how’d that trade off as an environment for spinning a generator?
If it’d work, generating electricity there, can that be done putting the exhaust into the water deep enough that the CO2 dissolves rather than bubbling up? Or are the methane clathrates unstable enough that warming up a little spot on top of one would risk the neighborhood?
Re #27 The money and perks available to IPCC people are extensive. If oil company scientists are unenthusiastic about GW, then it can be argued that IPCC scientists might be enthusiastic from the same kind of incentives.
It is my understanding that membership on IPCC panels is not highly remunerated. Nor do I see uncertainties played down in IPCC WG I reports. So not only is the attributed motive unsupported, even the existence of the infraction seems to me very much in doubt.
Perhaps Mr Pollard would care to proffer at least one specific instance where IPCC WG I understated scientific uncertainty.
WG I, however, and RealClimate, report on a rigorous physical science. RealClimate largely exists in response to unfair criticisms with unscientific motivations, directed at the science. This is the science summarized by IPCC WGI. The WG II and WG III reports, and the various policy responses including Kyoto, are outside the professional interests of the editors of this site, and are explicitly excluded as core topics in the description of the site’s purpose.
Climate science is not the weak link in climate policy, and attempts to make it appear as such are at best misguided, but are to all appearances often cynical and even malign. Like IPCC WGI, RealClimate is about how the climate system works, what we know about it, and what we don’t. Unlike IPCC WGI, RealClimate is also about responding to baseless critiques of the physical science.
Whether environmental impacts or economic decisions have been comparably well-studied or comparably even-handedly reported by IPCC should be treated as separate questions. I think that for the most part answers to such questions should be sought elsewhere.
There is a deeper connection between our religious myths and the climatologists effort at education.
We have seen the flood, more than one catastophic flood, in our recent pleistocene times. We have seen it get very cold and we have seen it get as hot as the the Teutonic goddess of the dead and daughter of Loki, named Hel would tell us.
But, we have never seen the polio virus until Dr. Salk showed it to us in 1952. So, our religious myths have little to tell us about it.
But we have known about Noah’s struggle with the last deglaciation, we never forgot. It is built in to us, our culture, we accept catastrophes. Our religions prepare us for them by preserving their history. Our religions tell us, don’t worry, the human race will grow back, it is all part of God’s plan.
The heroic king Manu, son of the Sun, the first Hindu man predicted the great deglaciation and was instructed what to do by the great climatologist of his time, the god Vishnu. Modern climatologist cannot compete with that expert.
Been there, done that. You want our appreciation? Go tackle a tiny virus.
[Response: Gunther Anders, the philosopher of catastrophe, makes very effective use of a parable based on Noah in explaining the difficulty in convincing people to react to warnings of natural catastrophe. I learned about Anders work from an excellent little book, “petite metaphysique des tsunamis,” by Jean-Pierre Dupuy, given to me by my colleague Remy Roca. I highly recommend it.]
Re 27
I suspect that much of the problem may rest in Working Group Three – the “social science” part of the operation – and therefore not subject to the rigor of natural science.
Since WGIII has little if any involvement with the science it’s hard to see how it could be the origin of the problems you describe. In any case economists are probably the best-paid discipline in academia (with a low share of funding from government) and so ought to be particularly well insulated from the kinds of motivations you imply.
The IPCC process is merely a highly visible tip of the iceberg. Just as most sport takes place outside of the Olympics, the bulk of activity that winds up summarized in WGIII reports takes place in the wider world, e.g. in the academic literature, and funding for things like integrated assessment modeling is scarce.
It’s also hard to fault WGIII-types for lack of rigor or ignoring uncertainty. If anything, economists et al. have been particularly eager to explore things from an option value perspective and to use sophisticated tools, to offset the fact that the socioeconomic problem space is messier. If anything they could be faulted for measuring only what is measurable, but correcting that generally implies more stringent mitigation effort.
Wow! What an excellent article. Regarding the verified aspects of the theory I have a list of supporting evidence that I like to display to the skeptics when they ask “â?¦ what is the evidence that AGW exists?”
I reply as follows….realizing my list may need some refinement and that other trends may have been left out I’d appreciate any additions.
Basically every climatological trend I can think of is consistent with global warming theory.
– Global Surface temperature trends; 3 independent compilations that each show the same thing
– Satellite trends
– Sonde balloon trends
– Alpine glacial trends
– Precipitation trends
– Hydrological trends (cycle intensity)
– Arctic ice trends
– Arctic river flow trends
– Pan evaporation trends
– Ocean temperature trends
– Large lake temperature trends ( Tahoe, Tanganyika, Baikal)
– Drought trends
– heating day and cooling day trends
– record heat trends
– record cold trends
– snow line trends
– Lake freeze/ thaw trends
– permafrost trends
– Earth shine trends
– Spectrophotometric trends
– surface skin layer trends
– spring budding trends
– migratory trends
– atmospheric moisture trends
– cloud trends
– increased snow accumulation over the Antarctic and Upper elevations of Greenland do to increased moisture and precipitation.
– precipitation trends
– sea level rise trends
– atmospheric shrinkage trends
– stratospheric temperature trends
– sea surface barometric pressure trends
Re #1, #9, #15, #21 about Greenland glacier ice retreat:
The inland ice is thickening due to more precipitation and the edges are melting, due to higher temperatures. Satellite data are accurate for the inland ice, but less accurate for changes at the slopes and flow changes. The earlier Johannessen paper acknowledges this and says it is uncertain about the edges. Rignot and Kanagaratmna ignores the inland ice (as “in balance”, some discrepancy with Johannessen) and concentrate their findings to the edges.
In the (full) comment of Dowdeswell in Science, one of his first statements is somewhat out of reality:
This is certainly not true for the largest Greenland glacier at Ilulisat (Jacobshavn), which breakup point is receding already since (and probably before) 1850. The retreat was faster in the 1929-1953 (24 years) period than in 1953-2003 (50 years).
Thus the recent accelleration is within normal variability, the more that one need to take into account that less friction, due to the shift of the breakup point is increasing speed too.
And yearly average Greenland temperatures (where there are only stations at the edges, as the inland is inhabitable) now are just reaching the 1930-1950 temperatures, but summer temperatures still are lower. See the temperature plot of all Greenland stations here.
Thus the recent accelleration is not the result of GHG induced global or regional warming, as regional temperatures probably are NAO-correlated and are not higher than 50-70 years ago…
This doesn’t mean that there is no global melting for most other glaciers, be it that in general the melting started before the main GHG releases after 1950. And interesting to see that 8 out of 20 glaciers chosen by Oerlemans show a rapid decrease, but a relax after 1980 or even a growth. See the graph on RealClimate.
Raypierre,
Thanks for this nice article, although the ID/evolution controversy seems to be confined to the US. In Europe the ID adherents are a rather extinct species…
To add to your Afterword, I think that water is even better suited as ID molecule than CO2: the earth has it in all three forms in enormous quantities and rapid (external) changes are countered by the large heat buffer that are the oceans. Even at the largest extremes, some part of the surface still rests inhabitable by some species, thanks to water. If the temperature changes, a small change in cloud cover can (and does in the tropics and Arctic) counteract the more extreme peaks…
[Response: Yes, water is a very fine molecule, but it has a tragic flaw that makes it unsuitable to use all by itself in putting together a habitable world. It makes a planet subject to catastrophe on both the cold end and the hot end. On the cold end, because water ice floats, it makes a planet subject to an ice-albedo (Snowball Earth) catastrophe. On the hot end, it makes a planet subject to a runaway greenhouse. Regarding the latter, my own estimates show that if a planet is tuned to be habitable early in its history when the Sun is faint, then it will hit a runaway greenhouse after about 4 billion years, if there is no other regulation mechanism operating. Our current understanding of the regulation mechanism on the hot end is the CO2 weathering thermostat, though recent ideas have started to lean on methane and organic haze clouds as well. On the cold end, CO2 also helps a planet avoid falling into a snowball; buildup of CO2 is supposed to help a planet get out, but my work shows there are some problems with that idea — which could be resolved if there were a good way to make high clouds in a system without much water in it and with feeble convection. Another case of water not doing the job one needs it to do. ]
This is off topic somewhat. Texas republicans seem unimpressed by global warming. What parts of Texas could be flooded in next 50-100 years if Greenland proceeds to melt? Texans who own land in those areas might be interested.
[Response: For Texas, other relevant things to look at would be summertime heat waves, drought, effect of these on air pollution and on agriculture, and potential double-whammies in coastal areas from increased hurricane intensity and sea level rise.]
Here’s a nice map of SE US coastal changes for various degrees of sea level rise. Texas doesn’t quite make it on there.
http://www.gfdl.noaa.gov/~tk/climate_dynamics/fig5.gif
Anyone have any similar maps handy?
You must remember this, Bogey and Bergmann. What one black robed lawyer on the bench giveth, another can just as easily take away. What is worse than a lawyer? A lawyer who becomes a judge.
Ay yup, judge Jones done good this time, and he may know some science; but putting your hopes in the bag of legal rhetoric is folly.
There is a profound gypsy curse (I repeat, curse) – “May your life be filled with lawyers.” Lawyers love it; they have a complete monopoly.
It’s called due process in the legal trade.
Re: George Balella (34). I think you would find relatively few AGW skeptics who would disagree with your list as evidence for GW (ie. global warming). What none of this list would demonstrate is: that climate change is unusual or unexpected; that GW is anthropogenic; that the current temperature trend is outside natural trends (that ocurred before high levels of CO2 emissions); that the current temperature is the highest in the past 1000 yrs (this is inferred only by the proxy studies – which have very high levels of uncertainty).
60 Minutes on GW tonight, 2/19/06 (CBS)
re 34
Alright the global temprature has gone but I doubt that you can prove CO2 is the cause.
“Actually, when skeptics make any semblance at all at playing by the rules of science,”
How scientific is to ask everybody to believe that CO2 causes global warming when you know that it cannot be directly proved and there could be any number of other explanations for it?
How nice to see a discussion of intelligent design and a mention of Rubisco.
For if there is ‘evidence’ of ID it is Rubisco -God’s deliberate mistake – indeed perhaps THE forbidden fruit whose mortal taste will bring ‘death unto the world…..’
Not that upregulating its expression would do much of interest.
Its defect is that cannot sort out oxygen from carbon dioxide, so while it adds Carbon to the plant it also burns it (back into CO2).
-If Rubisco didnt have this defect there might be very little co2 in the atmosphere at all -and there might be no upper limit to its oxygen concentration (please extinguish your cigarettes).
Of course, life processes on all inhabited planets are going to appear ID, a posteriori, but that surely the fun of exploring the idea at school in science lessons.
We also need to create something to replace the Acts of the Apostles et al (post Dawkins) for those who do need something as succour.
Consider the pineapple!
Hi Brian,
What would you consider “proof” that CO2 is the primary cause of GW?
Hi Coby
Certainly not a computer model which can prove anything provided the period of time is short enough .
I would want a direct proof, not one based on two readings with two different instruments separated by anumber of years.
[Response: You don’t seem to have understood the article, or the nature or the argument. There is very basic physics that predicts that increasing CO2 should lead to warming. Two things that could moderate this link are the behavior of water vapor and the behavior of clouds. It’s increasingly clear from water vapor observations and advances in the theory of how water vapor behaves that water vapor is very likely to amplify CO2 induced warming as the theory predicts. Clouds are still in a more uncertain column. The earth is warming in a way that the CO2 theory predicts. That doesn’t say that its’ the only possible theory that could account for the observed warming, but the observed warming is indeed consistent with the theory. If you think that some other theory could account for the warming, then it is up to YOU to show that this meets the observations equally well. Better people than you have tried, and failed. If you think you can do it, by all means go ahead. –raypierre]
Brian,
There was a reason I put proof in scare quotes, and that is because there is in fact no such proof possible. We will never have anything more than very strong evidence and very high certainty, that is the nature of science, proof is for mathematics.
What we do have is a theory of how climate works that is based on very solid physics and that is internally consistent. It is further consistent with a mountain of empirical evidence (data) and supported by very sophisticated computer models.
When I asked what you wanted to see as “proof” I was wondering if there was some observation you would need to see confirmed before you would believe CO2 is causing warming. If the above (theory based on hard science, consistent with obsevations) is not enough for you then nothing ever will be. I would also note that if this is the case, you must instead believe in magic as all the technology around you was developed using the same scientific methods that underpin AGW theory.
“The earth is warming in a way that the CO2 theory predicts.”
How so?
When I look at global temperature and CO2 concentration charts I see only a poor correlation and the two graphs actually diverge for 35 years between 1940 and 1975. How is this consistent with CO2/GW theory?
[Response: Your question is dishonest, since you’ve asked it and been answered before: http://timlambert.org/2005/11/milloy-spreads-lie/ – William]
An excellent post, very good reading.
Slightly off topic, I was particularly interested to see the latest Carl Wunsch paper in press at Quaternary Research. Entitled ‘Abrupt Climate Change: An alternative view’ its a provocative read (not really a surprise for a Wunsch paper!) and I think well worthy of comment here at RC.
Keep up the good work.
nanny_etc: As has been pointed out a number of times when you have raised this point, a refinement of GW/CO2 Theory incorporates the radiative effects of aerosols, emitted by volcanoes and fossil fuel burning, and other radiative forcings [land-use change, solar]. Consequently, the theory predicts that there would be warming in the early 20th Century due to a number of factors [land-use change, solar, relative lack of volcanic aerosols, some CO2], cooling in the mid-20th Century [Anthropogenic aerosols now being dominant], and warming in the late 20th Century [as CO2 becomes more dominant than aerosols due to its longer atmospheric lifetime and clean air legislation].