The New York Times's masthead motto is "All the news that's fit to print." The Australian's might as well be "All the news that fits our prejudice."
Don Aitkin is of course entitled to his opinion (though as the late Senator Moynihan reminded us, he is not entitled to his own facts). The paper could have run his piece as an op ed on the inner pages (though for what purpose, I don't know). But by running it with the prominence they have, you have to wonder at their motivation. Don Aitkin is a political scientist, no doubt eminent in his field. But no one can pretend he is an authority on climate science. What's more, his article contains nothing of any novelty. So what purpose can there be in not only publishing the article, but in giving it the prominence of a page 1 placement? All I can think of is that The Australian wishes to continue to stoke controversy -- whether to generate circulation (which doesn't work with me, I stopped buying the paper) or to pursue its own agenda on climate science.
However, since they have done this, and in addition, posted a lengthier paper (an address he gave to the Planning Institute of Australia), his views demand rebuttal. Here it is, based on the lengthier paper.
- Arguing about "consensus" is silly. There was a consensus before Einstein's time that Newton had the Laws of Physics stitched up. Einstein found a more general theory. "Consensus" in science is not a deep concept -- just a way of expressing the fact that most scientists do not see the point in arguing over something that has been shown to be valid, and no one has successfully invalidated. There was a similar "consensus" about the link between tobacco and cancer, which the relevant industry attacked vigorously, using similar language to the anti-AGW movement. That consensus remains to be overturned, despite the fact that we still have a lot to learn about the mechanisms of cancer.
- He claims that he is "presently agnostic about the central Anthropogenic Global Warming...proposition" but this is not borne out by his article, which dwells on arguments against AGW. To quote Monty Python, that's not debate, it's contradiction.
- The "panicky media mood" he talks about is no reason to trash the science, rather to be skeptical about the quality of science journalism in popular media. There was a similarly panicky media mood about global cooling in the 1970s (he quotes Newsweek further on) but if you actually search the scientific literature, there was very little basis in science for this. I don't think you will find a "panicky mood" if you read Science or Nature. A paper has been published showing that 7 papers in the 1970s predicted cooling, compared with 42 predicting warming. The cooling papers attracted only 12% of the citations counted. In other words, even in the 1970s, the evidence available at the time -- Newsweek and other popular media notwithstanding -- was that warming was more supportable than cooling.
- Einstein and Feynman on refutation and uncertainty in science: the anti-AGW movement can be accused of a higher degree of certainty with considerably less evidence on their side. Read Bob Carter's polemics. Is there a hint in any of his writing the he could be wrong? On the contrary, there is a bellicose certainty in his writing which I have not found in the scientific literature -- which I find odd from a scientist of his experience (here's a classic example).
- "...human beings barely understand 'climate'". Well of course this is a vast field but enormous strides have been made over the last 20 years. I have been following this issue over that period, and the scope and accuracy of the models have improved vastly. To speak of the field in terms that were true 20 years ago is misinformed, I'm afraid. Models developed over that time have for example accurately predicted the effect on climate of a major volcanic eruption.
- Urban heat island effect -- I suggest he reads the literature on how this effect has been isolated out. For example, warming in the Arctic cannot be explained by this effect. Studies have been done eliminating urban sites to see if they skew the trend, and statistical techniques like jackknifing have been applied to determine whether a fraction of the stations is skewing the trend. There is an excellent discussion of this issue at the RealClimate site.
- Reduction in measuring stations -- the reason for this is the introduction of satellite-based measurement. Satellites can measure bigger areas more accurately (though they do need careful calibration, the source of some of errors which have since been put right).
- Uncertainty brushed aside -- this is simply untrue. Measurements and model outcomes are given with a range of values to allow for the uncertainties in measurement and modeling. Uncertainties in IPCC reports are expressed numerically (90% probability etc.).
- "IPCC, for example, discredits satellite-based measurements, perhaps because they are lower). But let all that pass too." If he didn't mean the reader to take this into account, why mention it? This is a rhetorical trick befitting a shaky legal case not a serious academic argument. As I pointed out earlier, satellite measurements are subject to a period of calibration, as is true for any new instrument.
- Wine-making in England: this is skimpy evidence at best for unusual warmth. Wine is grown in England on an even bigger scale now, and has been for years. It's also grown in much cooler climates (Germany, Canada: have you heard of Eiswein?). The literature on the medieval warm period is subject to much greater uncertainties than the modern climate record, and that the world as a whole was warmer (as opposed to a few regions) has not been established. It is a bit rich to complain of the IPCC brushing aside uncertainties, then accepting the "medieval warm period" as fact, without any doubts as to the accuracy of measurement.
- "... we don't know what the 'normal' production of CO2 is". The natural carbon cycle is very well understood. Try looking for papers by Berner for example.
- He correctly points out that the greenhouse effect of CO2 is logarithmic, then goes on to look for a "dramatically linear relationship". Why would you expect to find a linear relationship if the effect is logarithmic?
- The claim that the warming of the troposphere doesn't match models arises from improper handling of uncertainties (where have we heard that before?).
- IPCC and sea levels: the IPCC's 2007 numbers are lower than their earlier numbers because they took out the area of greatest uncertainty, ice loss. This is not reassuring. The behaviour of the Antarctic is deviating from models significantly, including much more rapid ice discharge than predicted. If you want to criticise the IPCC for inadequate handling of uncertainty, this is the place.
- "... slight cooling in the sea" -- again, a problem with calibrating new instrumentation. See the note at the head of the press release that started it all. Prof Aitkin may be a novice at climate science so one could forgive him the lapse of failing to check for follow-up studies. This error has been known for almost a year. But Bob Carter was advising him. Surely he can't be that incompetent. Or is he dishonest?
- Antarctica: the West Antarctic Ice Sheet is cause for concern. It is grounded below sea level (up to 2km in parts) and if it destabilized, it could come apart quickly, adding around 5m to sea levels. The problem is that we don't have good models to predict its behaviour. There is evidence of very rapid ice loss in the distant past, but no evidence of the mechanism.
- Climate models versus weather prediction. I've seen this argument often and it doesn't improve with age, unlike a good wine (British or not). Climate is a long-term effect, averaged over many years. Weather is an instantaneous measure (what you see now). I can predict with reasonably accuracy, based on decades of medical data, that flu cases will increase over winter. I cannot, however, predict whether any individual will get ill at all, let alone when. Should we stop advising the infirm to take flu shots, because we don't know which of them will succumb? One of the great advances in the twentieth century is the science of large numbers. We can do epidemiological studies, accurate censuses, and the like -- even though there are many errors in the data.
- Validity of models -- there are many climate models, not just one. They broadly show the same trend with small differences. If modeling the climate many different ways arrives at a similar outcome, it increases your confidence in the models. If a discrepancy is found, either the discrepant model is invalid, or the others are, and work goes into fixing the problem. This has been happening over a couple of decades. If you think this is not a very good approach, what would you advocate we do instead? Carry on as normal, and see if nothing happens? Is that a responsible position if the best science we can do, whether imperfect or not, says we are heading for trouble?
- He claims that the IPCC has extraordinary influence and that its work is political. I argue the opposite. If they had significant influence, we would have a much stronger worldwide agreement than Kyoto by now. On the contrary, the anti-AGW position is largely political (show me the scientific papers: I've found a few, but they are not convincing); I refer you again to the style of Bob Carter. If you think the language of the IPCC Summaries (for policymakers, note, not for scientists -- responsible policymakers will in any case run the detail past their own scientists) is not very scientific, look again at the Carter article I referred you to earlier (not an isolated example).
- "... tendency of scholars to 'protect' their theory" -- I suggest he takes a step back and looks at the anti-AGW position in the same light. Lindzen for example persists with his "iris" theory even though he has no hard evidence to back it (and there's a very fundamental reason that it is unlikely to be right -- ask nicely and I'll explain).
- "... quasi-religious view" -- again, look at the anti-AGW position. Many of its proponents aren't scientists, or are retired scientists. Their orthodoxy is being challenged, and they are putting up a bitter fight. Similar opinions were expressed about tobacco and cancer, and the ozone hole. What is a scientist who finds that an industrial practice is harmful to do? Shut up and live with the consequences, or speak out and be accused of "religion" or "politics"? Take a step back from the anti-AGW position, and ask yourself what you would do faced with that situation.
- Influence of "Greens and environmentalists" -- now he is moving into the political. Is he saying that NASA's labs, the UK Antarctic Survey, et al. are mainly populated by Greens and environmentalists? This is where the science is coming from. I've been in science for over 20 years, and my experience is that scientists are significantly more conservative on average than his end of academia. That there is a Green vote no doubt influences governments to take some kind of action, but you can be sure that as long as that vote is under 10%, that action will be tokenism at best.
- "... if there is no true causal link between CO2 and rising temperatures" -- there is. The physics is well established. The only cause for uncertainty is the feedbacks (e.g., extra heating caused by reduced albedo).
- "I ask for a public inquiry" -- what purpose would this serve? The detail of the science is beyond the non-scientist, and any scientist can look up the relevant literature. The IPCC is an enquiry of a sort, but he rejects it; would the anti-AGW camp accept any finding they didn't like? His supposition is that the IPCC was set up with the AGW hypothesis set as truth. However, thousands of scientists working on the problem had every opportunity to refute it. Some have pointed out problems, most of which have been addressed, as he would have found had he followed up his limited literature review with a search for citations. There is in fact considerable reward in demonstrating flaws in the science because so few people are doing it -- hence the entry into the field of previous unknowns like Lomborg (would any conventional funding agency have funded him? Only one journal publication, and not in a relevant area ... or now that Aitkin's no longer involved in funding decisions, does he no longer accept track record as a criterion for funding research?) Why are so few people doing it? Is it because the "consensus" is substantially right? Because of a conspiracy?
- "... ensure that the funding directed to climate science research be allocated in a disinterested way" -- does he have any evidence that it's not? Again, I point to Lomborg. No track record, no relevant scientific background, yet he was able to attract significant funding. If you want to look for political interference in funding, look no further than his case.
- "... started to think through how to find alternatives to oil" -- James Hansen at NASA, often accused of being alarmist, has also pointed this out.
- "likely to be attacked and demonised" -- I have seen this claim often but I have yet to see a real instance. Lomborg for instance was attacked largely on the poor quality of his science, which he took personally. The Australian has plenty of articles "attacking and demonising" the IPCC position (how would you classify his?) He may find, however, that some people are annoyed by the fact that he is raking over old arguments that are easy to refute. I was annoyed enough to write this lengthy rebuttal when I have better things to do with my time.
The only part of Aitkin's paper which makes any sense is where he points out that there are other good reasons to aim for a cleaner, greener planet. Well good. Why, then, muddy the waters by pontificating at length on matters on which he is not qualified and which he clearly does not underestand?
As a courtesy to other readers, please provide references (not just a web site or an organisation please: something that can be found) if you have information to add. I do not feel obligated to respond to unsubstantiated claims to the same extent.
Follow-Up
Predictive Power of Models
One of the comments on this article claims, "To put it simply, models have got better at being tweaked to match historical climate but no-one has the faintest idea of how good they are at predicting future climate." In other words, the models have no predictive power. I took this as a challenge, and compared one of the earliest papers with reality.
Antarctic
Also since the Antarctic has been the subject of some discussion, I though this picture may be of interest:
The picture (sourced from NASA) shows the warming trend around the Antarctic, 1982-2004. As you can see warming around the edges is very significant, but much of the interior is cooling. The overall picture is consistent with the view that the region is warming, but the special properties of the continent with its extremely massive, high ice cap are causing it to deviate from the trend.Consensus
I was accused of talking nonsense when I spoke of "consensus". Another area where this term is used in in evolution. As with climate change, effects are long-term and can't be observed directly. If most evidence points to a particular view and there is scant evidence to the contrary, it is reasonable in science to talk about "consensus" emerging. It is simply not true that a scientific theory can only exist if you can directly demonstrate its validity experimentally. Evolution and geology operate on multi-million-year timescales; cosmology on even longer timescales. We can no more recreate the steps leading from simple organic molecules to multicellular beings (at least in some cases) possessing intelligence than we can recreate the steps from the instant of creation of the universe to countless millions of stars as we know them. Nor can we experience climate change directly and change its course by a simple experiment. None of this means that we cannot have valid scientific theories in these areas -- only that testing them is hard, and those who refuse to be persuaded have an easy time developing arguments that seem compelling to the non-scientist.
Satellite data
One of the comments said:
Satellite-based measurements are more accurate - I agree - and the calibration issues have been resolved. Both the University of Alabama (Huntsville) and RSS are now producing very similar temperature data and .. I suppose to your dismay ... it's showing little sign of warming.
It took me a while to get to this and ... why should I be dismayed? If the problem is going away we can all breathe easy. As it turns out, recent corrections show that errors in Christy and Spencer's work significantly underestimated the warming trend.
Sea Level Rise
Here's something I found recently on sea level rise and the potential for a rapid meltdown of ice caps, based on paleoclimate studies:
Jonathan T. Overpeck, Bette L. Otto-Bliesner, Gifford H. Miller, Daniel R. Muhs, Richard B. Alley, and Jeffrey T. Kiehl. Paleoclimatic Evidence for Future Ice-Sheet Instability and Rapid Sea-Level Rise, Science, vol. 311 no. 5768 24 March 2006, p, 1747-1750.
20 comments:
Philip
I didn't bother to go past your first point, because your claim that, in effect, science operates by consensus is total nonsense. The examples of consensus you cite (the tobacco-cancer link and Newton's laws) were not consensus based at all, but based on extensive data collection, observation and objective analysis, that lead to the logical conclusion that these theories were very highly likely to be correct. That is a scientific conclusion and not a consensus. In contrast, the AGW theory has yet to reach anywhere near the same levels of probability of being correct. Putting figures on it, the probability that the former two theories are correct is > 99.9%. The best the high priests of AGW theory can come up with is about 90% (ie less than 1/100th as certain. Even that is opinion and not objectively demonstrated; despite the massive amounts of research that has gone into attempting to scientifically verify the theory.
In fact, there are plenty of observations that do not fit with or even contradict the AGW theory as it stands; some of which are noted by Aitken. How for example can you explain that the region on earth that is most likely to suffer a greenhouse effect; Antarctica, is not on average warming at all? Even though West Antarctica is, the average is not; ergo, the rest of the continent is actually cooling! Compare this to the most similar climatic region on earth; the Arctic, which is actually heating faster than anywhere else in the world...In scientific terms, these observations are the equivalent of Newton's apple falling up and not down. For Newton's law to survive in the face of such observations, you would need to explain the forces that counteract gravity in the observed case of the apple falling up. In the case of AGW, the same applies; you need to explain contradictions such as these, or else as Popper points out, the AGW theory is in fact false.
You misunderstood my first point. I did not say science operated by consensus but rather that consensus is the loosely accepted idea that it's a waste of time to rehash areas where agreement is broadly reached.
As for the tobacco vs. climate science situation, the arguments are the same. It was very late in the day that a direct gene-damage link was made to a carcinogen in tobacco. Up to then, the evidence had all be epidemiological, i.e., evidence based on large-scale statistical studies. Climate science is in fact on a firmer base. The models are based on well-understood principles of physics. Statistical methods are needed to handle uncertainties in the measurement. In this respect, the fundamental understanding of what's going on is more advanced than with the tobacco and cancer link. The only major cause for doubt, in both cases (beyond the usual caveats that science can always be invalidated -- but if that concerns you, you should never use a bridge) is vested interests.
It's not true that the Antarctic is not warming at all. The Antarctic peninsula is the fastest-warming region of the planet, even if it's a relatively small part of the Antarctic.
Much of the rest of the continent is experiencing warming but not as yet at a statistically significant level.
The Antarctic's warming response is damped by two effects. The southern hemisphere has much more ocean than the north, and there is a massive quantity of ice, some over 2km above sea level.
All of this fits the mainstream climate models. There is no contradiction.
Measurement of temperature in the Antarctic is especially difficult because of the harsh terrain and difficulties in satellite measurement during Antarctic storms. For this reason, we have a poor record of the overall situation, and making categorical claims as you do only supports my point, that the denial camp looks for certainties yet accuses the other side of failing to allow for uncertainty. See also this article in Nature on why we can't make useful predictions.
The poor state of Antarctic temperature measurement does not prevent us from seeking other direct evidence of warming, for example, rapid break up of ice shelves. Larsen B in 2002; more recently the Wilkins Ice Shelf. There's also an accelerating trend of glacial retreat on the continent.
What a lot of nonsense Phillip.
1 - There is no demonstrable consensus about climate science. The only IPC sonsensus is from government representatives who agree that the report is an accurate summary of climate science, not that the science is correct.
2 - Various Journals and news outlets discredited them selves yeasr ago. In 2002 the editor-in-chief of Science declared that the science was settled when it was obvious back then that it wasn't. The journals and media are very aware of readership and advertising revenue. If readership dropped due to a lack of alarmist stories they wouldn't like it one little bit.
3 - It's not for sceptical scientists to disprove man-made warming. It's up to the believers to prove their case. In the absence of any scientific papers showing irrefutable evidence of man-made warming I believe that everyone should be sceptical.
4 - "the scope and accuracy of the models have improved vastly" .. that's a line we've been hearing or reading for years. To put it simply, models have got better at being tweaked to match historical climate but no-one has the faintest idea of how good they are at predicting future climate.
5 - There's no link between urban heat Island Effects and localised warming in the Arctic. You should know that perfectly well. The UHIE is very likely an issue when attempting to calculate the average global temperature from a series of near-surface measurements. Far too many observation stations now come under the temperature influences of nearby towns and cities.
5 - Satellite-based measurements are more accurate - I agree - and the calibration issues have been resolved. Both the University of Alabama (Huntsville) and RSS are now producing very similar temperature data and .. I suppose to your dismay ... it's showing little sign of warming.
6 - "Measurements and model outcomes are given with a range of values to allow for the uncertainties in measurement and modeling." That's rubbish and you (should) know it. I recently read an alarmist and widely cited 2007 paper from James Hansen and he mentioned 3/4 degree + or - 1/4 at point but later forgot all about it and made all kind of asuumptions of accuracy on just the 3/4. No error margins for him because people would see that the range of values was 2/3 of 1 degree, and that's very high for temperature data.
7 - "Uncertainties in IPCC reports are expressed numerically (90% probability etc.)" ... more nonsense. Scientific claims are expressed with (highly subjective) ratings of uncertainty. Newton wasn't 93.5% about gravity, ws he?
8 - The literature about the Medieval Warm period is well established and is supported by numerous temperature proxies. (Not proxies based on trees because temperature is not the only factor in their growth.)
9 - Th anatural cycle of carbon dioxide is poorly understood. Absorption has recently increased (i.e. less remaining in the atmosphere) because of the La Nina. The movement (extent and drivers) of oceaninc absorption are poorly understood and little is known about how much settles on the ocean floor. Read the literatue and you'll find CO2 in teh atmosphere known to 3 decimal places but oceanic precipitation estimated in millions of tonnes.
10 - The latest IPCC sea level figures are based on a technique of estimating historical levels from a statistical calibration of recent monitored sea levels with the prevailing weather conditions and seasons. This ignores issues such as geological movement (uplift, fall) and is probably very dicey when it comes to the interplay of seasons, winds and ENSO events. Why am I slightly uncertain? Because the method has been poorly disclosed, especially the vital matter of accuracy.
11 - The seas have in fact cooled. For sea surface temperatures take a look at the NOAA maps and data. For the temperatures down deeper try the recent paper about that, you know the one, it's where the author tried to find all the possible excuses for the data being cooler than he wanted/expected.
I'm runnign out of time now so I'll huryy.
- Of course the IPCC is political. It's not much more than a government-funded lobby group that greatly influences government spending on climate-related matters. It has always attarcted those scientists who believe in man-made warming and it's charter directs it to assess the risks of a human-influence on climate. Why on earth would anyone claim it's impartial?
- The partial collapse of the Wilkins Ice Shelf shows no sign of being anything other than natural. The press statement from NSIDC/BAS was just a beat up ... for funding(?), exposure(?) or political purposes(?). The fissure started to develop between March 2007 and July 2007, during the late autumn and early winter when temperatures were low. Winter temperatures in that part of the world have jumped around all over the place and cloud cover since 1998 has shifted away from low cloud and toward mid-level cloud, so I can't see any human influence in that.
Philip
The tobacco story is a good example. Long prior to establishment of causal means, as you note, we still had very strong epidemiological evidence which said there was a very high probability (>99%) of a link between tobacco and cancer. That is an objective measurement. We do NOT have that for climate change; if we did, then for example, average global temperatures would be tracking rises in GHG levels far more closely than they are. They are not, so we have to rely on a consensus view.
You also sink your own argument with respect to Antarctica and end up supporting the thrust of mine. Firstly you note that western Antarctica is warming faster than any other area of the planet, and then say that the rest of Antarctica is not warming because it is covered in ice and surrounded by a huge area of sea. Last time I looked, that was also so for West Antarctica, so you have the paradox here ultimately revealed. Either West Antarctica defies your explanation, or the rest of Antarctica does. Which ever is correct, you must conclude that one of the two defies predictions made according to the AGW theory.
I also note that you blame "vested interests" for the doubts about climate change. That is a very stereotypical response, a very poor excuse for rational argument and no excuse whatsoever for ignoring the points raised; as is also usual for the greenhouse religion. What is Aitken's "vested interest"? I'll tell you what mine is by the way; if AGW theories turn out to be right, then I will make a small mint; or perhaps more like a large mint. If you need it spelled out any more clearly, by adopting my current position, I am actually arguing against my vested interest. Can you please explain how that stands up with your theory?
Greetings Paul,
I love the web! Thanks for putting up the link to your blog. I am very strongly of the opinion that anthropogenic global warming is real, but that the probability of a catastrophic 'tipping point' are vanishingly small and that the costs of adapting to the effects of global warming are much less than the costs of futile attempts to stop it.
I am a card-carrying scientist...
Please, climate skeptics, drop by and read this on why we think anthropogenic global warming is true; true believers, drop by and read the lot. Please.
I'm not sure if we are arguing here whether consensus is important or not but in any case, show me the literature that refutes the "mainstream". There's a very small group of scientists plugging away at this and they are not convincing compared with the overwhelming majority. That's not a vote, it's weighing the evidence.
Now a reputable journal like Science only sells because it's alarmist. Please stick to plausible points otherwise you don't win anyone over.
UHI and Arctic: the point is that if the temperature trend was solely an artifact of UHI, we wouldn't be seeing the strong heating trend we do get in the Arctic.
Antarctic: either you want to base everything on absolute certainty, or you don't. Temperature measurement in the Antarctic is hard and records are patchy. That's a fact.
University of Alabama (Huntsville): could this be what you are referring to? I must say this is a bit of a puzzle. Christy claims that the standard models predict greater warming in the tropics which is exactly the opposite to what I've seen everywhere else.
The misconception some of you are coming from is that I want the AGW theory to be correct. Nothing would please me more than to discover it wasn't because experience tells me that if we really need global action to turn it around, there's little chance it will happen in time.
What does not help the case is vituperative bile such as we see from some in the anti-AGW side, and snidely dismissing science which looks reasonable and valid. I haven't read the specific Hansen paper cited here, but he has been the subject of beat-ups before (e.g., his early models showed a range of scenarios and some in the anti-AGW camp have conveniently only taken his worst case which he himself said was unlikely, and used this to claim he was out by a factor of 3).
If you guys want to claim the other side is duplicitous, you are hardly making a case by using tactics like this. Further, I try to give references for my claims so they can be checked. NOAA has masses of data (thanks for the pointer but something specific would have been helpful) but I'll try to track down their numbers.
Chris Fellows: thanks for dropping by. I'm happy to read your views as well as all the other stuff I've plowed through.
Your thickness amazes me.
Just how difficult do you think it is to publish papers sceptical of man-made warming? What? You think the peer-review system is credible and above broad? Soeems like you have a lot to learn.
A journal like Science sees the editor rejecting papers that he doesn't like or sending them to reviewers that he knows will trash them. What? You still believe that the publication of scientific papers is a fair and impartial business? Where have you been?
You are the first person I've read who has tried to claim that anyone thinks the ONLY reason that temperatures have risen is because of UHI. All my learned colleagues - try finding some - will tell you that over the last 50 years temperatures have risen for (very probably) natural reasons and they have fallen for natural reasons. They will also say that there is very likely some underlying distortion brought about by the UHI effects on near-ground temperatures.
I was referring to observed temperatures at the Rothera and San Martin bases in the Antarctic. Read that sentence again - I said "observed". Yes, generalising across Antractica is difficult but it's more than that - it's foolish to claim that you know what land based temperatures are when there's no observations there.
I was referring to UAH data of lower tropospheric temperatures. Apparently you are unaware that these figures are published every month.
"The misconception some of you are coming from is that I want the AGW theory to be correct. Nothing would please me more than to discover it wasn't because experience tells me that if we really need global action to turn it around, there's little chance it will happen in time." Put the viloin away. Your raison d'etre would disappear if you didn't have man-made warming to carry on about.
You didn't respond to my other points so I'll take it that you agree with them.
What vituperative bile? We've put up with ad hominem attacks and gross unsubstantiated assertions from the warm-aholics for years. It looks like you're being rather precious. My heart bleeds ... from laughter.
In response to "What vituperative bile?" may I quote your words to you: "Your thickness amazes me."
I am offering you the opportunity to post your views here without censorship. If you feel you are making a case by being rude, I am not going to argue.
On UAH data of lower tropospheric temperatures: I have read this report, which claims to have fixed significant though not all discrepancies. Christy's comment only refers to temperatures, not the atmosphere, which threw me off track. Surface temperature trends in models generally do increase less in the tropics. Thanks for the correction.
See my next article for a more detailed response on some points raised here.
UHI: it is you who is claiming there is no significant temperature trend outside of natural variability. If you isolate out rural stations including the Arctic, this is one of many techniques for eliminating UHI bias. Following from your logic, if you haven't answered my other points on how UHI bias can be eliminated, can I take it you agree that the problem can be satisfactorily handled?
It's hard justify to responding to every point by someone who does not post their name (I don't know which of the anonymous posts are the same person for example) or provide references. But feel free to continue to post here. I'll try to get to your other points as time allows.
Anonymous says:
models have got better at being tweaked to match historical climate but no-one has the faintest idea of how good they are at predicting future climate.
This is a common misconception of denialists. Models are not in any way "tweaked to match historical climate." The only climate data that goes into the models is grid data -- the albedo, elevation, terrain type and average cloud cover of each grid point. The rest is physics, and the improvements have all been in how to model physical effects. For instance, the first radiative-convective model of Earth's atmosphere (Manabe and Strickler 1964) used a fixed vertical distribution of absolute humidity to allocate water vapor, while a later one (Manabe and Wetherall 1967) used a fixed distribution of relative humidity, which matched empirical data better.
Anonymous repeats:
[[Th anatural [sic] cycle of carbon dioxide is poorly understood.]]
No matter how many times you repeat this, it still won't be true. The carbon cycle is very well understood, thanks to the efforts of such scientists as James C.G. Walker, James Kasting, Hays, Berner, Lasaga, and many others. Your ignorance of the field doesn't mean the field doesn't exist.
Anonymous posts:
[[What vituperative bile?]]
You have to be kidding.
You keep saying consensus is meaningless and so is peer review, because scientists are prejudiced and as suppressing research which disagrees with them. Leaving aside your gross ignorance about how modern science operates -- e.g. the fact that it operates by consensus and peer review -- your ad hominem remarks about how scientists deliberately distort the truth and suppress opposing research are nothing if not personal attacks. Who do you think you're kidding?
I find this debate very interesting, but somewhat dysfunctional.
I am most interested in the points raised by climate skeptics but it seems to me that no one here is making any concessions, so the debate isn't moving forward. i.e. can we identify which points raised by skeptics like "anonymous" do actually contribute to uncertainty about AGW and which points do not contribute to uncertainty because they have been rigorously addressed? Can skeptics then agree that some of the points raised have been sufficiently dealt with so that we can concentrate on the ones that are really still important?
I guess that we are mostly scientists here, so it strikes me that the debate is so unscientific! Why the impoliteness, what benefit is there to claim that people/ideas are nonsense, idiots, kidding etc.?
If everyone would cite specific references that would help us readers a lot too!
Thanks, and keep up the good discussion.
Thanks, Brad.
The denial case would be more strongly made without personal attacks and the harping on evidence that's easily refuted like wine production in England. Of course some of these people have run into personal flak as well, but I didn't do that, so I do not accept that I should be a target of rudeness. To me that comes across as not having a case.
I recognize that there are some genuine scientists out there with genuine concerns, but I don't expect any of them to post personal attacks. I would be happy if they would provide links to research that clarifies the picture. Robust debate is fine. I have no problem with that.
I accept that there are big problems with modeling something as complex as the climate. What I am not seeing from the denial side is what their alternative is. As far as I can tell, it's sit back and see what happens.
Some may consider "denial" some sort of insult, but as long as the case being put is that the only possible flaw in the modeling is that it's pessimistic, I can't think of a better term. If there are indeed significant flaws in the models, as we should acknowledge, what about the possibility that the error is on the optimistic side? Someone examining both sides of the potential errors would in my book be a skeptic.
Would have responded directly to Barton Paul Levenson, but couldn't find an email.. sorry to clutter up your comments! Just wanted to point out that the carbon cycle is not cut and dried, there are serious problems with some of (most of?) the modelling of transport of gases across the air/water interface. In 2006 I went to a talk by a physical chemist who talked about how mass and heat transport are coupled: you can’t calculate the flux of carbon dioxide from water to atmosphere and vice versa just by looking at the concentrations, you need to know the relative temperatures too. I worked out his equations in Excel, and a gas will move against a pressure gradient if it is moving with a temperature gradient: i.e., if the air is hotter than the water, the concentration of carbon dioxide in the water will be higher than in the air.
This physical chemist wrote two papers on this in 1991-1992 in the climate scientists’ journal of record, Geophysical Research Letters (Phillips, Leon F.. Carbon dioxide transport at the air-sea interface: Effect of coupling of heat and matter fluxes. Geophysical Research Letters (1991), 18(7), 1221-4.; Phillips, L. F.. Carbon dioxide transport at the air-sea interface: numerical calculations for a surface renewal model with coupled fluxes. Geophysical Research Letters (1992), 19(16), 1667-70.) As of last year the papers have each been cited exactly four (4!) times. I found a paper from 2003 by a collection of climate scientist chaps from Princeton and other places, who estimated carbon uptake in various places and come to the conclusion: ‘there is more carbon dioxide uptake at low latitudes, and less at high latitudes, than the models predict.’ This is because the physics in those models is wrong.
Thanks, Chris. That's good information. There's also the question of how the ocean's rather complex chemistry which includes a thing called "life" will respond to a less alkaline environment. A lot of unknowns -- but I would still argue that the big picture is well enough understood to estimate in roughly the right ballpark. What we want to know is whether we are heading for climate change rapid enough to be harmful.
There have been papers recently suggesting that natural sequestration is slower than predicted. Possibly your issues are part of the cause. As with other uncertainties in the modeling, my concern is that reality could be worse than any of the models.
Hello All,
why is it that web comments on any article related to climate change, no matter how specific the origional article, end up as tit for tat "it's true" or "it's not true".
Thanks Phillip for your rebuttal of the Australian's article by Don Aitkin. It made me so angry that such conjecture and pure nonsense could be published by an acaedamic of high standing. Since when were political "scientists" called upon to review the work of climate scientists. I certainly didn't see the Australian publishing articles by Jim Hansen about the demise of the Liberal party. It is perfectly within Aitkin's ambit to discuss political and policy reaction to climate change but for him to question the basic science is ludicrous.
Thanks, Peter. Don Aitkin is by no means the only person of his standing to have done something like this. It is becoming quite fashionable. I only wish we could get a history professor to write something on gravitation waves, to vary the fare. But I don't blame him: he is entitled to his opinion and as long as he is willing to debate it intelligently, there is no big problem. I do have some difficulty with The Australian giving the article undue prominence because he wasn't really saying anything new, and he lacks the background to repeat claims of others with increased authority. That said, some of the responses posted here illustrate the deeper problem: that there are some not really open to reason, who are somehow getting editorial space (even if they can't publish significant research for whatever reason).
"Validity of models -- there are many climate models, not just one. They broadly show the same trend with small differences. If modeling the climate many different ways arrives at a similar outcome, it increases your confidence in the models."
But how much actual difference in the underlying assumptions in the models? If they have the same assumptions, then, yes, the trends will be similar. CO2 forcing alone accounts for only a portion of warming trend, and rest is water vapor and cloud feedback. If the models have similar assumptions wrt water vapor feedback, then the model accuracy rests on the accuracy of such assumptions.
The number of models is irrelevent to assessing their validity. It's all about the data matching the models that validates or invalidates them.
. and you have folks claiming the data falsifies estimates -
http://rankexploits.com/musings/2008/ipcc-projections-overpredict-recent-warming/all-comments/#comments
- for the simple reason that natural climate variability factors have turned recent temperature trends down (last 8 years).
anon says: "AGW theory has yet to reach anywhere near the same levels of probability of being correct."
IMHO, its talking about the key nub of skepticism, but that's not a well-formed way of stating it. AGW theory is partly physics (well-founded) and partly climate modelling assumptions (some wellfounded some speculative).
ONE CAN TRUST ASPECTS OF THE AGW THEORY WITHOUT TRUSTING THE MODELS. We shouldnt trust models without good validation mechanisms, even if we think AGW theory is right. One way is to cross-check side-result of historical trends with models. There have been reported errors & contradictions in some cases (cloud cover differences, precipitation estimates off, etc).
http://www.weatherquestions.com/Roy-Spencer-on-global-warming.htm
Spencer on cloud cover feedback
Anonymous:
If you want to test the models, see my next article.
You can't separate out a trend of 2 or 3C per century in 8 years. If you look at the earliest instrument record of annual temperature variation (before industrial pollution was worldwide) e.g. HadCRUT3, you will see that there is a variation of about 0.5C without a statistically significant trend (I looked at HadCRUT3 for the first 50 years). If you take this as "natural variability" a trend of 0.03C per year can hardly be expected to be discernible over 8 years. It won't break out of natural variability; try a period of 15 years + or just test the "trend" that's exciting you for statistical significance.
Cloud feedback: here's a thought experiment for you. The earth's orbit changes, inducing an increase of 4W/m^2 in net energy flux. Would you expect the cloud feedback effect to damp this increase? Yes? Then how did warming well above the current trend occur in the inter-glacials? No? Then why is this source of 4W/m^2 different from the same increase in net energy resulting from AGW?
I found the discussion at this site fascinating. The "skeptics" argued themselves hoarse that proxy data couldn't be accurate, forgetting that they are the ones with a case to make that the Medieval warm period can be accurately compared with today. If you dismiss all the evidence as inaccurate, the best you can do is say we can't learn from the past, not that your preferred version of the past is correct. Hint: if you are really a skeptic, you question all sides of the debate, not just the one that you dislike.
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