In a departure from normal practice on this site, this post is a commentary on a piece of out-and-out fiction (unlike most of the other posts which deal with a more subtle kind). Michael Crichton’s new novel “State of Fear” is about a self-important NGO hyping the science of the global warming to further the ends of evil eco-terrorists. The inevitable conclusion of the book is that global warming is a non-problem. A lesson for our times maybe? Unfortunately, I think not.
Like the recent movie “The Day After Tomorrow”, the novel addresses real scientific issues and controversies, but is similarly selective (and occasionally mistaken) about the basic science. I will discuss a selection of the global warming-related issues that are raised in between the car chases, shoot-outs, cannibalistic rites and assorted derring-do. The champion of Crichton’s scientific view is a MIT academic-turned-undercover operative who clearly runs intellectual rings around other characters. The issues are raised as conversations and Q and A sessions between him (and other ‘good guys’) and two characters; an actor (not a very clever chap) and a lawyer (a previously duped innocent), neither of whom know much about the science.
So for actors and lawyers everywhere, I will try and help out.
The issues Crichton raises are familiar to those of us in the field, and come up often in discussions. Some are real and well appreciated while some are red herrings and are used to confuse rather than enlighten.
The first set of comments relate to the attribution of the recent warming trend to increasing CO2. One character suggests that “if CO2 didn’t cause the global cooling between 1940 and 1970, how can you be sure it is responsible for the recent warming?” (paraphrased from p86) . Northern Hemisphere mean temperatures do appear to have cooled over that period, and that contrasts with a continuing increase in CO2, which if all else had been equal, should have led to warming. But were all things equal? Actually no. In the real world, there is both internal variability and other factors that affect climate (i.e. other than CO2). Some of those other forcings (sulphate and nitrate aerosols, land use changes, solar irradiance, volcanic aerosols, for instance) can cause cooling. Matching up the real world with what we might expect to have happened depends on including ALL of the forcings (as best as we can). Even then any discrepancy might be due to internal variability (related principally to the ocean on multi-decadal time scales). Our current ‘best guess’ is that the global mean changes in temperature (including the 1940-1970 cooling) are actually quite closely related to the forcings. Regional patterns of change appear to be linked more closely to internal variability (particularly the 1930’s warming in the North Atlantic). However, in no case has anyone managed to show that the recent warming can be matched without the increases in CO2 (and other GHGs like CH4).
Secondly, through the copious use of station weather data, a number of single station records with long term cooling trends are shown. In particular, the characters visit Punta Arenas (at the tip of South America), where (very pleasingly to my host institution) they have the GISTEMP station record posted on the wall which shows a long-term cooling trend (although slight warming since the 1970’s). “There’s your global warming” one of the good guys declares. I have to disagree. Global warming is defined by the global mean surface temperature. It does not imply that the whole globe is warming uniformly (which of course it isn’t). (But that doesn’t stop one character later on (p381) declaring that “..it’s effect is presumably the same everywhere in the world. That’s why it’s called global warming”). Had the characters visited the nearby station of Santa Barbara Cruz Aeropuerto, the poster on the wall would have shown a positive trend. Would that have been proof of global warming? No. Only by amalgamating all of the records we have (after correcting for known problems, such as discussed below) can we have an idea what the regional, hemispheric or global means are doing. That is what is meant by global warming.
Crichton next raises the apparently unrecognised (by the lawyer character at least) fact that the interior of Antarctica is cooling (p196), an issue discussed in another post (Antarctica cooling, global warming?). This is more or less correct (given the obvious uncertainties in long term data from the continental interior), but analogously to the example above, local cooling does not contradict global warming.
Next, and slightly more troubling, we have some rather misleading and selective recollection regarding Jim Hansen’s testimony to congress in 1988. “Dr. Hansen overestimated [global warming] by 300 percent” (p247). Hansen’s testimony did indeed lead to a big increase in awareness of global warming as a issue, but not because he exaggerated the problem by 300%. In a paper published soon after that testimony, Hansen et al, 1988 presented three model simulations for different scenarios for the growth in trace gases and other forcings (see figure). Scenario A had exponentially increasing CO2, Scenario B had a more modest Business-as-usual assumption, and Scenario C had no further increases in CO2 after the year 2000. Both scenarios B and C assumed a large volcanic eruption in 1995. Rightly, the authors did not assume that they knew what path the carbon dioxide emissions would take, and so presented a spectrum of results. The scenario that ended up being closest to the real path of forcings growth was scenario B, with the difference that Mt. Pinatubo erupted in 1991, not 1995. The temperature change for the decade under this scenario was very close to the actual 0.11 C/decade observed (as can be seen in the figure). So given a good estimate of the forcings, the model did a reasonable job. In fact in his testimony, Hansen ONLY showed results from scenario B, and stated clearly that it was the most probable scenario. The ‘300 percent’ error claim comes from noted climate skeptic Patrick Michaels who in testimony in congress in 1998 deleted the bottom two curves in order to give the impression that the models were unreliable.
Dr Hansen is further quoted (a little out-of-context) saying: “The forcings that drive long term climate change are not known with an accuracy sufficient to define future climate change”. Given the discussion above it is clear that without good estimates of the actual forcings, the differences in the model projections can be large. It is widely accepted that exact prediction of what will happen to climate in 50 or 100 years is impossible. Much of the future is of course unknowable. A new energy source could replace fossil fuels, governments could control emissions, or maybe a series of huge volcanoes will erupt. Therefore it is much more sensible to ask, what would climate be like if you doubled CO2? or if this or that scenario occurred. These are much better defined questions. Hansen’s quote is often taken to imply that models are so unreliable they are useless in helping assess the issue. In fact it is the opposite – Hansen is actually claiming that the uncertainty in models (for instance, in the climate sensitivity) is now less than the uncertainty in the emissions scenarios (i.e. it is the uncertainty in the forcings, that drives the uncertainty in the projections).
Continuing to p315, it is claimed that “in the 1970’s all the climate scientists believed an ice age was coming” (and, as described on p563, the MIT academic apparently still thinks so). However, this is not an accurate statement and William Connolley’s pages on the subject are an illuminating read for those wanting more details.
Another issue that often comes up in discussion about the surface temperature record is the impact of the Urban Heat Island Effect (UHIE), and here it appears on p370. It is undisputed that the centres of cities such as New York are significantly warmer than the surrounding countryside. This issue has been extensively studied and is corrected for in all analyses of the global temperature trends. To see whether there might still be a residual effect in the corrected data, a recent paper (Parker, Nature, 2004) looked at the differences in the trends if you looked separately at windy and not-so-windy conditions. Wind is known to diminish the impact of urban heating, and so the trends on windy days should be less than trends on still days if this was important. The trends actually end up almost exactly the same. Other validating data for the corrected surface temperature record comes from the oceans, which have also been warming in recent decades. Even Richard Lindzen , normally an arch-skeptic on these issues, stated that “ocean temperature increases present some support for the surface temperature record” Lindzen (2002). Another demonstration that the corrections are sufficient is that over the continental US, where many cities have a clear urban heating signal, the mean of the corrected data is actually rather flat (p88) – i.e. none of the strong urban biases in the US has made it into the regional or indeed global mean.
A central issue in the book concerns sea-level rise. Vanuatu is singled out for special attention since the islanders there are understandably concerned about their low-lying islands eventually being swamped. Sea level however is a surprisingly difficult thing to measure. Tide gauges are very noisy, and are usually located on the continental coast. Global trends in sea level from these gauges are between 1.7 to 2.4 mm/yr. Sea level though is not rising everywhere. In Scandinavia the continents are still rebounding from the ice age and local sea level is receding. Satellite data (TOPEX/POSEIDON and JASON) can give a global picture, and indicate that although the global mean rise over recent years (2.8 mm/yr) is significantly larger than the longer term trend estimated from tide gauges, sea level change is actually very dynamic. There are many patterns of behaviour particularly in the Pacific, associated with El Nino variability – possibly related to Vanuatu’s lack of actual sea level rise over the last 40 years. Curiously, Crichton cites the higher satellite derived number to claim that the rate of sea level rise has not increased recently (“[Sea level is] rising faster, Satellites prove it”,”Actually they don’t”), p424. There are clearly some problems in comparing tide gauge and satellite data, and of course, satellites can have their problems (cf. MSU data), but the quoted numbers don’t support the actual statement at all – though it would be fairer to say that the satellites are consistent with a recent rise in the rate, rather than a proof that it is occurring.
There are only a few out-and-out errors, but to be generous, they probably just slipped through the editing process. For instance, on p187 “higher temperature means more water vapor in the air and therefore fewer clouds” – Presumably, he meant that if the temperature is higher, the relatively humidity could be lower (and so there might be less clouds). On p368. “Croplands are warmer than forested lands”. This is probably a confusion with the urban heating issue, but the actual impact is the opposite – croplands have a higher albedo than forests, reflect more solar radiation, and are thus cooler. In fact, while this is not yet fully quantified, it appears to have been a significant cooling term in the global budget over the last 150 years. On p461 “…Greenland shows that, in the last hundred thousand years, there have been four abrupt climate change events” More like 40. And that is probably an undercount given that Greenland may not record events in the tropics.
At the end of the book, Crichton gives us an author’s message. In it, he re-iterates the main points of his thesis, that there are some who go too far to drum up support (and I have some sympathy with this), and that because we don’t know everything, we actually know nothing (here, I beg to differ). He also gives us his estimate, ~0.8 C for the global warming that will occur over the next century and claims that, since models differ by 400% in their estimates, his guess is as good as theirs. This is not true. The current batch of models have a mean climate sensitivity of about 3 C to doubled CO2 (and range between 2.5 and 4.0 degrees) (Paris meeting of IPCC, July 2004) , i.e an uncertainty of about 30%. As discussed above, the biggest uncertainties about the future are the economics, technology and rate of development going forward. The main cause of the spread in the widely quoted 1.5 to 5.8 C range of temperature projections for 2100 in IPCC is actually the different scenarios used. For lack of better information, if we (incorrectly) assume all the scenarios are equally probable, the error around the mean of 3.6 degrees is about 60%, not 400%. Crichton also suggests that most of his 0.8 C warming will be due to land use changes. That is actually extremely unlikely since land use change globally is a cooling effect (as discussed above). Physically-based simulations are actually better than just guessing.
Finally, in an appendix, Crichton uses a rather curious train of logic to compare global warming to the 19th Century eugenics movement. He argues, that since eugenics was studied in prestigious universities and supported by charitable foundations, and now, so is global warming, they must somehow be related. Presumably, the author doesn’t actually believe that foundation-supported academic research ipso facto is evil and mis-guided, but that is an impression that is left.
In summary, I am a little disappointed, not least because while researching this book, Crichton actually visited our lab and discussed some of these issues with me and a few of my colleagues. I guess we didn’t do a very good job. Judging from his reading list, the rather dry prose of the IPCC reports did not match up to the some of the racier contrarian texts. Had RealClimate been up and running a few years back, maybe it would’ve all worked out differently…
Update: Due to popular demand here is an updated version of the figure that was originally made in 1998. Apologies for my lack of photoshop skills.
Update 02/16/05: Chris Mooney also does a good job at checking some of the footnotes in Crichton’s book.
Dear Dr. Schmidt:
In my comment #43, I asked: “What justification is there for the IPCC projecting that methane will increase by an average of 12.5 ppb per year for the next 60 years?”
You didn’t reply. I assume you can’t think of any justification, either. The only possible justification I can think of is a collective case of “methane madness.”. It certainly doesn’t appear that methane will increase by an average of 12.5 ppb for the next 60 years, based on recent trends.
I also asked: “What justification is there for the IPCC projecting that CO2 concentrations will increase by an average of 3.2 ppm per year for the next 60 years?”
You didn’t reply directly to this. But possibly you replied indirectly, when you wrote, “However, it is not inconceivable that the current rate of growth of 1.4%/yr in fossil-fuel related emissions could reach 2%/yr or more due to rapid economic growth in the developed world.”
‘However, it is not inconceivable’ Hmmm.
Over the last 5 years, Barry Bonds of the SF Giants has hit 258 home runs. That’s an average of more than 51 home runs per year. “It is not inconceivable”that Barry Bonds will average 51 home runs per year in the next 5 seasons. But next season, Barry Bonds will be 39 years old, so the probability that he will average more than 51 home runs a year for the next 5 seasons is very low – almost certainly less than 1 chance in 10. In my opinion, the odds that human emissions of CO2 will increase by an average 2% per year or more for the next 30 years is lower than that (i.e., lower than 1 chance in 10). What is your estimate of the probability that CO2 emissions will increase by an average of 2% per year for the next 30 years?
Finally, you conclude, “the probability of a warming as low as 0.8C over the next 100 years is extremely low.”
I disagree. In my opinion, the probability that the lower troposphere will warm by ‘as low as 0.8C over the next 100 years’ is approximately 50 percent. What is your ’50 percent probability’ estimate for global warming in the lower troposphere over the next 100 years?
Response: Let me try again to make my position clear, since you obviously failed to grasp the point earlier. I (and other climatologists) are not in the business of fortune-telling. I do not know what CH4 or CO2 levels will be like in 100 years time. This may come as a shock to you, but it really shouldn’t. So, given my ignorance on what the future may bring, I therefore attempt to bracket the possibilities through the use of a number of different projections -some produced by IPCC, and others created in-house (such as Hansen’s ‘Alternative Scenario’). Some of these have large increases in CO2 and CH4 while some have smaller changes in CO2 and reductions in methane – and it is correct to consider all of them, precisely because they are conceivable, not because they are necessarily likely. Unless you understand this, there is no point in continuing to dicuss.
With respect to the uncertainty in CH4, I will add that the growth rate has changed from over 10 ppb/yr in the 80’s to close to 0 ppb/yr over the last few years. Since we don’t have a full understanding of why this is, it is premature to assume it will continue. There are a number of factors that control CH4 concentrations that are extermely poorly understood and are mostly ignored in the scenarios – the dependence on other gases (such as O3, and CO), the impact of increased temperatures and changes to precip on tropical and boreal wetland emissions, the existence (or not) of a significant methane hydrate source from permafrost or continental shelves, the climate impact on the atmopsheric chemistry of CH4. Throw in a huge uncertainty as to whether commercial exploitation of methane hydrates is possible and what impact that may have, I am quite comfortable in projecting a range of variations for CH4 levels in 100 years time.
However, there are good reasons to expect CO2 levels to continue to grow. Any conceivable growth rate (even a constant 1.5ppm/yr) will add by 2050, another ~1W/m2 to the climate forcing. Add in the current radiation imbalance of ~1 W/m2, you have at least 1.5 deg C surface warming to come (assuming a canonical 0.75 C/W/m2 sensitivity). So I repeat, the probablity of only 0.8 deg C warming by 2100 is extremely low. You are entitled to your opinion, but your estimate is apparently just based on you saying so. – gavin
Gavin
re : the Hansen graph (thanks for your efforts btw)
Which temperature record are you using. I assume it is the GISS (Land + Ocean) record, but which is the mostly widely accepted record CRU or GISS.
Don’t the IPCC use the CRU record?
Response: It’s usually a good idea to have two or more groups try and produce the same ‘record’ using different methodologies. The GISTEMP data are processed differently from the CRU data, and I don’t have any particular reason to prefer one over the other. In most respects they are extremely highly correlated and so it doesn’t matter much which you use. – gavin
“So I repeat, the probablity of only 0.8 deg C warming by 2100 is extremely low.”
When you say this, are you referring specifically to greenhouse gas forced warming, or warming overall?
One of the things I’m having trouble with is the uncertainties of aerosals and their effects on cooling, or the possibility of volcanic eruptions producing particles that result in cooling. It seems like there’s a good many factors that could offset warming – many of them unpredictable and relatively unstudied and not quantified.
I’m not suggesting that an alcoholic with liver problems should keep on drinking, hoping something else will come along and fix his liver.
But I’m trying to understand the confidence level in the totality of these predictions vs. the narrowed scope of forcings from greenhouse gases. Would particle forcings be irrelevant long-term as they don’t have the lifespan of grenhouse forcings? And could temporary stability switch to more radical climate change if these kinds of forcings offset greenhouse gases over the next century?
Thanks.
Response: The different timescales do make a difference. Because aerosols only stay around for a short time (weeks), the concentration goes like the emissions (i.e. double the emissions to double the concentration). For CO2 however, it goes like the accumulated emissions over past decades to centuries. Thus to keep up with the CO2 warming, the emissions of aerosols would have to go up exponentially. For various reasons this is not going to happen (not least because of negative public health effects), so eventually CO2 is going to ‘win’. In fact, it is much more likely that aerosol emissions will decrease in coming years. However, aerosols are complicated and include both absorbing and reflecting types, and have complex interactions amongst themselves and with atmopsheric chemistry. Therefore our uncertainty about their future impacts are high. Due to the timescale issue though, that uncertainty will be less and less important as CO2 increases. Volcanic aerosols have a clear cooling effect (c.f. Pinatubo, El Chichon, Mt Agung) but judging on past frequencies/explosiveness are unlikely to have much impact on longer time scales than maybe decadal. My comment about the unlikeliness of 0.8 deg is about the overall warming, which by 2100 is much more likely to be dominated by CO2 than the present warming. – gavin
I’m not a scientist in the area of geoclimate or the environment (I do have a background in physics and numerical computation). So I appreciate the expert comments addressing inaccurracies in the book (I read it).
A point that comes across in the book is that these models shouldn’t be trusted without significant empirical evidence, particularly when policy is being based on them. And I tend to take the book’s side on this perspective. (The poster seems to be focused on computational models as part of his research)
[Response: The best place to start looking at the models and their comparison against reality is the IPCC report chapter 8. The vast wealth of scientific work on validation of models appears to be ignored in the book – William]
I respect that climate scientists employ highly complex and intensive models to describe and simulate the most complex phenomena in nature. Due to the enormous complexity of the subject, these models tend to lack the tighter coupling with empirical evidence – when contrasted in an area such as computational physics (when validated by theory and experimental results).
As a outsider, I wonder how many variables are hidden? How much precision, drift or inaccuracy builds up due simply to limited computational power? How are results are skewed due to a trend in the use of certain statistical approaches? What are the limitations caused strictly by the numerical approaches? What focus has been put on understanding and improving the sensors themselves? All the same things that effect every computational models – but are exacerbated by a problem which seems intractable (modelling the climate).
To any experts out there, what are the guidelines for interpreting results from a computational models? What has worked? What doesn’t? What percent of climatology research is based on these models?
It seems that there is enough evidence to support or argue either perspective of global warming (or other major climate models/theories).
Crichton’s science was abysmal in Prey, an anti-nanotech screed. I wrote a review explaining just how bad. It seems he’s continuing the trend. Let’s get the word out: Crichton is *not* any kind of scientific authority.
Chris
In your response to posting 51 you say “However, there are good reasons to expect CO2 levels to continue to grow. Any conceivable growth rate (even a constant 1.5ppm/yr) will add by 2050, another ~1W/m2 to the climate forcing. Add in the current radiation imbalance of ~1 W/m2, you have at least 1.5 deg C surface warming to come (assuming a canonical 0.75 C/W/m2 sensitivity). So I repeat, the probablity of only 0.8 deg C warming by 2100 is extremely low. You are entitled to your opinion, but your estimate is apparently just based on you saying so. – gavin”
1. Why do you say “ANY conceivable growth rate…will add..another ~1W/m2…” when the discussion is about the IPCC’s claim of a 1% growth rate (about 3.8ppmv) and the long-term observed rate which is less than 50% of that figure? Surely a difference of more than 50% in input values will produce different output values.
[Response: I meant “..at least 1W/m2…” If the actual concentrations grow faster than 1.5ppmv/yr, the forcing will obviously be greater. – gavin]
2. Over in https://www.realclimate.org/index.php?p=13 we find “In other words, CO2 does not initiate the warmings, but acts as an amplifier once they are underway.”. Can you explain why you say that increased CO2 is causing warming but this other article says that increasing CO2 merely amplifies existing warming?
[Response: Post 13 is talking about inter/glacial transitions in the assumed absence of human forcing. In those cases, there is no obvious reasons to assume that CO2 would inititate the forcing (though one could think of some if required). In the current case, there is an excellent reason to think that CO2 is initiating the forcing – we can watch it accumulating and we know we’re doing it – and the short timescales rule out astonomical forcing – William]
I note that if CO2 merely amplifies warming then the reasons for warming remain unquantified and this casts doubt upon climate models. Conversely I note that if CO2 directly causes warming as you appear to be claiming, the fact that ice cores show that temperatures increased about 800 years before a CO2 increase (and a latter decline in temperatures before CO2 levels declined) casts doubt upon CO2 as a driver.
Please tell us how many degrees of warming we can expect from a 10 ppmv increase in atmospheric CO2 if no other climate factors are varied. In other words, let’s see your base value for CO2-induced warming before we consider the influence of the various positive and negative feedbacks. – John
[Response: if you want to know, you can read the appropriate numbers off the graphs in the IPCC reports, though you may need to clarify your question a bit – William]
[Response#2: The standard for comparing responses across different models is to look at the radiative forcing at the top of the atmosphere – for 2xCO2 it is around 4 W/m2 (read the new National Academies report on this for a much more detailed discussion of the concept). Temperature responses to that radiative forcing have to involve at least some feedbacks (LW, Sensible Heat, Latent heat, evaporation, etc.) so your question is a little ill-posed. In a simulation with a simple mixed layer ocean, the temperature response to 2xCO2 once all the fast feedbacks have happened is around 3 deg C (current range among models being analysed by IPCC is 2.6 to 4.1 deg C). Note that 2xCO2 is the preferred test since the impact of 10 ppmv depends on the base amount of CO2 (i.e. 280+10 ppmv has a different response that 380+10 ppmv due to the roughly logarithmic change of forcing with CO2 level). – gavin]
I read the IPCC summary of the climate models, and was impressed by the last sentence:
“The overall assessment of coupled models was that “current models are now able to simulate many aspects of the observed climate with a useful level of skill” and “model simulations are most accurate at large space scales (e.g., hemispheric or continental); at regional scales skill is lower.”
That is not exactly a ringing endorsement.
Several questions on models:
1) Has anyone run these against known initial conditions circa 1800 to determine how well they replicate known climate over the succeeding 200 year?
2) As the resolution of models has increased, is there any trend regarding the predicted temperature changes?
Also, am I reading the last graph incorrectly, or is the climate acting a whole heck of a lot like scenario C?
Response: The IPCC statement is a fair assessment of the current state-of-the-art and could be paraphrased as saying that models are not perfect, but they are useful. No modellers have ever claimed anything different. Simulations from the pre-industrial to the present are being done all the time, and are currently being heavily analysed for the next IPCC assessment. The main result is that the global mean temperatures (including short term dips as well as the recent rise) are actually well modelled when you include as many of the forcings as you can. (I will post a discussion about this soon, including figures to make this clearer). At a regional scale the simulation are not as good a match because of uncertainties in the regional distribution of aerosol forcing, the fact that there is simply more variability at regional scales, and the noted performance issues of the models at that scale.
As resolution increases many things improve (such as the definition of frontal structures , storm tracks etc.) , however there is no indication that climate sensitivity is a strong function of resolution, that is much more tied to the physics in the models.
Scenario C has the same forcing until 2000 as Scenario B, after which it is constant at 2000 levels. The apparent difference between them earlier on is simply due to the chaotic nature of the system (i.e. the different ‘weather’ in each simulation). In the real world, forcings continued to increase after 2000, much closer to scenario B. – gavin
Thank you–your reply is very thorough and informative.
There are many scientists who think we are entering the next ice-age. The temperature of the Earth’s surface is not static, and has changed considerably (in many-thousand year cycles). Quite frankly, there isn’t uncontroversial scientific evidence either way. In the meanwhile, environmentalists use this propaganda to lobby statists into grabbing even mroe power. See this article and this article.
POINT ONE: You missed Crichtons point in his prediction of a rise of 0.812436 degrees C/
Quotes from his book follow:
. “Nobody knows how much of the present warming trend might be a natural phenomenon” .or..” man made.”
. “Nobody knows how much warming will occur in the next century. The computer models vary by 400%, defacto knowledge that nobody knows. But if I had to guess… I would guess the increase will be 0.812436 degrees C.”
.”I think that for anyone to believe in impending resource scarcity, after two hundred years of such false alarms, is kind of weird”
. “The ‘precautionary principle’ properly applied forbids the precautionary principle. It is self-contradictory.”
. ” I am certain there is too much certainty in the world.”
.”Everyone has an agenda except me”
When taken in context Crichton is predicting EXACTLY 0.812436 degrees. He obviouly knows ONLY TOO WELL that 6 significant figures is absurd. AND HIS PREDICTION IS STILL JUST AS GOOD AS EVERYONE ELSE’S, given all the uncertainties you all are talking about.
POINT TWO Similar comment on Eugenics- the point is that Politicians, state Governments, the US Supreme Court, the media, the public, & concensus CAN be wrong when implementing policy. We once believed in in a flat earth.
QUESTION: Why on common sense grounds is CO2 a more significant driver of the greenhouse effect & warming than water vapor? With water vapor at 2-4% ~40,000ppm & increasing, & CO2 at 379ppm and increasing HOW can CO2 be significant? If you claim that CO2 initiates other impacts, amplifiers etc then why is the impact of sunspots decreasing cosmic rays decreasing clouds NOT JUST AS IMPORTANT(AND EQUALLY JUST AS UNKNOWN.) Likewise for the uncertainty associated with water vapor driving clouds etc?
Why is it justifyable for Ca EPA , Sierra Club etc to claim that CO2 is the biggest cause of the greenhouse effect when quite clearly water vapor is larger. When you answer that with anything containing manmade only – then answer WHY is man made CO2 any different from nature made?
Finally please account for ice age length variations in CO2/warming back when man was not producing it. AND the possible error (30-50ppm?)in connecting ice core CO2 measurments with the Keeling measurements.
WHICH ALL leads back to Crichtons other point – nobody knows enough to say for sure.
SO WHY make policy on this basis?
Especially when a decrease in CO2 translates to a direct decrease in the 99% of energy production from fossil fuels.- BASIC chemistry- burn a hydrocarbon & get energy plus CO2 plus water vapor. Decrease the CO2 and decrease the energy!!- which leads to, in my opinion, guaranteed suicide for the world’s poor.
Response: [There’s no need to SHOUT!] Crichton’s point is indeed obvious, but, in my opinion, incorrect. We do not know “nothing”. We actually know quite a lot (but not everything). Using what we know is better than pretending that we know nothing. I argued above why 0.8 is extremely unlikely, and why not all projections are created equal.
The consensus issue is being debated on another thread.
With respect to water vapour, you are repeating a common misconception. Water vapour is indeed the most important greenhouse gas (and no climatologist has ever disagreed). However, the amount of time that any individual water molecule is in the atmosphere (the lower part at least) is around 10 days. Thus water vapour can be considered to be in a dynamic equilibirum with the surface conditions, trace gas amounts and aerosols on time scales longer than a month. Therefore water vapour levels in the atmosphere are a feedback and not a forcing, and are always modelled as such. The reason why CO2 (and CH4 and CFCs and N2O and O3) are important is because they absorb in parts of the spectrum where water doesn’t have much impact. There is a small potential for the direct forcing of water vapour by changes in irrigation patterns, but this appears to be small on the global scale.
Your other points are dealt with here (cosmic rays) and here (ice core CO2) and here (why not all CO2 is equal). – gavin
Yeah, those damn environmentalists – have so much power now and keep grabbing for more ;^! They’ll be forcing car companies to make EVs any day now (oh, wait, they did, but the government caved).
You know: I find it perplexing that this “novel” is found in bestselling science fiction. By rights it should be found in
HUMOR. Seriously, claiming that global warming is fabricated simply because a continent was cold for a decade really cracks me up. Come on. If people were really so fear stricken by global warming; would Bush have won the election?
I’d like to finish by stating the following:
1)Thanks to Michael Chrichton’s babbling, heresay-based idiocy, I may never be able to watch Jurrassic Park again.
2)I think that eco-terrorists has a subliminal connection to Greenpeace. Believe me, ecologists are the last people that should be regarded as a terrorist threat.
3) The September 2004 edition of National Geographic has a large section on Climate Change. It is far more credible than this ridiculous excuse for a book.
4) As a note to anyone interested, there is a forth factor in Global Warming. It’s called human ignorance: once that is defeated we’ll be well on our way.
P.S. There is well written book called “Stormy Weather: 101 Solutions to Global Climate Change. Read it and be educated, not decieved.
As an environmentalist I find it disheartening when other environmentalists adopt the “fair and balanced” methods of certain news organisations in order to force their opionions on everyone else. I believe that global warming may be a problem. I also believe we have very little climate data on which to base our computer models. As a computer programmer I understand the concept of GiGo (garbage in garbage out) when it comes to scientific models.
I do not believe an “argument” should ensue over the possibility of global warming. Rather, an open and honest discourse and acknowledgement of the fact that we are operating with very little information and we need to learn more.
All the shouting in this blog about who is right and who is wrong is not related to science in any way that I understand.
Too bad Crichton does not use some of his talents and energy to help anyone other than himself.
Preemptive strike: No, climate “data” from geological study does not enlighten or, if so, very little, since we must interpret it based on the meager and scant quantitiative data from the twentieth century and 4% of the 21st. We humans just have not been around all that long and we have been paying attention even less.
Of course, I am just one of the ignorant lay persons to whom so many references are made in this blog.
Cheers!
I’m curious that the discussion is so exclusively about temperature. It seems to me, in my lay understanding, that climate change is likely to be expressed as increased average global temperature plus increased mechanical energy in oceanic and atmospheric currents. Is the mechanical energy component being addressed elsewhere? Won’t increasing temperatures and wind pressures increase average humidity, thus forcing greater greenhouse energy accumulation? Wouldn’t increased weather activity suppress surface temperatures, making temperature a less useful measure of total change?
For a real science fiction novel (I don’t really consider Crichton to be a genuine writer in the genre, more a mainstream/horror hack using SF motivs) concerning GCC would be Kim Stanley Robinson’s “Forty Signs of Rain”. Though I can”t judge his use of scientific information in creating what speculative features he uses in his story, I can say his feeling of verisimilitude concerning the work of real scientists doing real science is infinitely more compelling than anything I’ve ever read from Crichton.
Crichton has done a great service to the science of Climatology by putting the topic of global warming on the front burner. This is fantastic! Of course his book is only a work of fiction, but playing the role of “devil’s advocate” is exactly what is needed to bring the argument out into the open. Too many political advocates of Kyoto and the IPCC models seem to want to suppress open debate, as if no intelligent person could possibly dispute the models.
But Crichton is intelligent, and a successful enough writer to put his objection into the public realm. His ideas will be widely discussed and debated. Nothing can stop that.
Instead of demonizing Crichton you should be praising and thanking him for the opportunity he has given you.
Someone here said it’s absurd to worry about extreme environmentalists being terrorist threats. Really? These are an arrogant group of people who think they should have the right to tell other people how to live. They find nothing wrong with the death of millions of people in the 3rd world, due to various environmental regulations (see DDT). They think that their theories — which are certainly anything *but* conclusive — give them a justification for interfering with the lives, freedoms, and property of others. And, of course, anyone who disagrees with them is an idiot, anti-earth, or just a greedy capitalist pig (“industry”).
It’s unremarkable to think of these people as terrorists. Look at what “animal rights” protestors do to the research labs of scientists who use animals: tresspassing, destruction of property, and violence. Animal rights is not the same thing as environmentalism, but there is overlap.
Re response to posting 56.
William, you say “In the current case, there is an excellent reason to think that CO2 is initiating the forcing – we can watch it accumulating and we know we’re doing it – and the short timescales rule out astonomical forcing” but you appear to be confusing a correlation with a definite connection.
Unless you can precisely explain and quantify the interaction between the correlated elements (and have it peer-reviewed and replicable) , you have nothing but an interesting coincidence and a strong hint that one or more external elements is driving those elements.
Gavin, in your response you resort to the dubious wisdom(?) of models. (Are you perhaps one of those scientists who validate ideas against models rather than against actual observations?)
Climate models are notorious for under-estimating radiation in the polar regions and for poor calculations of heat transfer from the tropics to the poles. Models are also exceptionally poor at dealing with one of the most common weather elements, clouds. (I note that a press release in the last few weeks said how difficult this has been and was proposing some new method.)
It seems to me that you (and many others) have decided that carbon dioxide is to blame before you have properly investigated ALL of the possible factors. To me that is irresponsible science!
John
Response: I am actually one of those scientists that spend almost all their time (when not answering needlessly aggressive posts like this) comparing models with data and seeing if my ideas fit both. I personally have looked at many different forcings, solar, volcanic, orbital, CO2, CH4, ozone, and aerosols and have investigated many different forms of intrinsic variability, as have many of my colleagues. The conclusion that I (and others) have come to is that CO2 is the biggest forcing over the last 100 years (followed by CH4 and aerosols) – this is not an assumption, it is a result. (see Hansen et al (2002) or vast literature cited by the IPCC report for the details). The conclusion that the CO2 increase is undoubtedly anthropogenic was discussed in another thread. With respect to my previous response, you asked an ill-posed question, I gave what I thought was a reasonable answer to what you actually wanted to know. If that wasn’t satisfactory, ask a better question. – gavin
You seem to be deleting comments with which you disagree. You only keep the comments that agree with you, or that you feel make easy straw men to knock down. This is not the mark of true science.
I am disappointed by your blog. You seem to re-iterate the same claims over and over, emphasizing the strength of your models and minimizing the weaknesses. Real scientists would emphasize the weaknesses and explain how they are going about making them stronger.
[Editor’s Note: Comments that get caught by our (admittedly imperfect) moderation filters will sit in the queue for a while before someone can get around to deciding to post or not. Anticipating that your previous comment (posted Dec 24 11:10pm) would recieve attention prior to your next comment (Dec 25 11:12 am), given the particular day in question, is possibly asking a little much of us. ]
In comment #66, Marvin writes, “You seem to be deleting comments with which you disagree. You only keep the comments that agree with you, or that you feel make easy straw men to knock down.”
I have had comments deleted here. (About a third of my comments have not been posted.)
But it’s simply wrong to say that RealClimate only keeps the comments that agree with their positions. Or that they only keep comments that are “easy straw men to knock down.”
I have posted here and intend to post again (when I have more time). I disagree with Gavin Schmidt: Dr. Schmidt seems to think that the temperature projections in the IPCC Third Assessment Report, or TAR (i.e., a temperature rise of 1.4 to 5.8 degrees Celsius from 1990 to 2100) are better than Michael Crichton’s projection of 0.8 degrees Celsius from 2000 to 2100. But the IPCC TAR projections are clearly worse, if one places the same range of temperatures around Michael Crichton’s estimates that exist in the IPCC TAR. That is, the IPCC TAR has a mean value of 3.6 degrees Celsius increase, +/- 2.2 degrees Celsius.
If Michael Crichton’s value of 0.8 degrees Celsius is taken with a range of +/- 2.2 degrees Celsius, it becomes a prediction of anything from a cooling of 1.4 degrees Celsius, to a warming of up to 3.0 degrees Celsius (with a mean value of warming of 0.8 degrees Celsius). Even assuming a warming of as much as 2.0 degrees Celsius from 2000 to 2100, Michael Crichton would still have a better prediction than the IPCC TAR (i.e. 0.8 degrees is closer to 2.0 degrees than 3.6 degrees is to 2.0 degrees).
As I noted, I will post again (when I have more time) on why Michael Crichton’s prediction is *better* than the predictions in the IPCC TAR.
Regarding comment 31: The IPCC projections are completely unrealistic, in part because:
1) They include completely unrealistic projections for future atmospheric methane concentrations, and
2) They include unrealistic projections for future CO2 emissions, and for future CO2 atmospheric concentrations.
The mistake you are making is assuming that the modelers are not already aware of the extreme nature of some of the projections. The goal is not to produce THE solution that will predict the future state of the climate system. That is clearly impossible. Although we like to think of model output as being deterministic (the solution my model gives is THE solution), the reality is far different. Because of our inability to capture the initial state of the atmosphere, imperfect data assimilation, parameterizations of some model schemes, etc., our deterministic model output is really a single member of a family of possible solutions defined by some probability distribution. This distribution says nothing about the real solution. If the model is a good one, then it is likely that reality will fall somewhere within the boundaries of the distribution. You also hope that by defining the distribution that some statements can be made about the most likely solution. The goal of the IPCC projections is to attempt to define the distribution of the GCM solutions. In order to do that a number of extreme scenarios are required. Without them, you cannot adequately define the distribution. So we have one that assumes that we are stopping our emissions right now (the best case scenario?) and we have one that amounts to the worst case scenario. Not surprisingly, the most likely solution appears somewhere between the extremes. Of perhaps more concern is the fact that the range of solutions is shifting toward increased warming with each IPCC report.
You seem very reluctant to post critical messages …
Its now two weeks ago.
Hi Gavin,
Using a different method to measure speed _only_ suggests a different speed, it cannot prove accelleration..
If a police man radars you a higher speed than you have on your dashboard what does this prove?
“Sir, my radar measurement suggests that you have been
accelerating” ?
From:
To:
Sent: Monday, December 13, 2004 12:36 AM
Subject: Re: [RealClimate] Please approve: ‘Michael
Crichton’s State of Confusion’
I know. That’s why I said ‘not necessarily’. It hardly
proves the opposite
though!
(Due to a slight problem, I’ve actually pulled this post
for the time
being, and so your comment won’t get posted either. It
should be back in
couple of days though – sorry for the confusion).
gavin
> A new comment on the post #74 “Michael Crichton’s State
of Confusion” is
> waiting for your approval
>
> Author : Hans Erren ()
> E-mail : erren21@…
> URL :
> Whois : …
> Comment:
> Sea-level rise
>
> Although satellite data (TOPEX/POSEIDON (sic) and JASON) shows a much
> steeper trend over recent years (2.8 mm/yr) than the long term mean
> estimates from tide gauges (1.7 to 2.4 mm/yr), each
method compared to
> itself does not indicate an accelleration.
This comment should probably be in a different place, but since several others raised related issues and I’m here….
Does responding to authors and books like Crichton and Lomborg make sense?
Yes and no.
Yes. As the current topic of general discussion, they provide a framework for discussing the broader issues. Any opportunity for engaging people in discussion is valuable.
No. The point by point refutation of the errors and biases merely results in those people who agree with the author’s premise bringing up other biased points of view from other sources.
The real problem is a lack of understanding about science and its process. A superficial understanding of “science” and the use of science in contexts like political science and social science, leads far too many people to the conclusion that if you present charts and graphs based on the past, the future can be predicted. Yet, the nature of charts and graphs is such that prediction seems to be magic.
The real “cherry picking” that occurs is due to a bias toward a specific political or social view of the world. The core argument is based on applying the principle that “anyone can see that the theory is wrong”.
When the winter is cold with lots of snow, clearly global warming is wrong.
When you consider the complexity of man and animals, the idea that we evolved from amino acids is absurd.
When you consider the change in ratio between the number of workers and the number of retirees, clearly Social Security is soon to fail.
When discussing the end of the oil age, the universal response seems to be “we will never run out of oil” and this comes from the oil industry and they MUST know the truth.
Yet, no one says, “gravity is not a weak force, because if it were, we would fly off into space”.
No one says, “quantum theories are bogus because even Einstein couldn’t believe that God places dice with the universe, and if merely observing the scene out the window changes the view which is just random events, then why does it look the same day after day?”
No one says “Einstein was and is wrong because you can’t see light bend around a lead cannon ball, and when have you seen matter converted into energy according to E=MC2? Look, I burn a cord of wood and most of the mass is converted into energy but I don’t blow up the world.”
After all, “theory is not fact”.
Yet, within the selective “scientific” refutation of “bogus theories”, we see lots of contradictions in the way this so called “science” is applied.
Ok, maybe there will be a shortage of oil in the future, but that is at least 20 years and probably 50 years in the future and technology will fix the problem. Yet, for Social Security, we have an immediate crisis that requires immediate action because of a $10 trillion short fall OVER THE NEXT 75 YEARS. Hmmmm, we never see that 75 year timeline emphasized by those who want to dramatically change the system immediately.
If technology will solve the oil problem and result in no crisis for oil, why won’t demographics or technology solve the Social Security problem over a longer time period?
There is a divide between those who think that we should “question authority” and those who don’t. I “question authority” no matter what the authority: the government, a book, the internet. I don’t do this out of disrespect, but to ensure that I understand enough to correctly interpret the theories, the observations, the conclusions.
The reason we have a field of study called “political science” is that it attempts to provide a methodology to examine history and develop political theories and from that suggest political policies. The science occurs when different voting systems are considered: the electoral college vs majority rule vs approval voting vs rank voting. It is not science to talk of Red States and Blue States or “values” being the factor that determined the election.
I find that even some of my most informed friends, people who explain to me what really happened with various space and aircraft disasters based on their own critical review of the available information on the subject, have problems discussing topics like global climate change, the end of oil as a fuel, because they haven’t even asked some obvious questions, much less done any research. How can someone go beyond the causes of either shuttle crash and question the ability of NASA or any equivalent organization to function effectively, yet simply accept that since The Limits to Growth predicted a crash due to resources by 2000 and that didn’t happen, global warming is bogus? The first problem is NOT QUESTIONING The Limit to Growth MYTH.
When told that the book forecast the collapse of the world by 2000, I reflected back on my buying the book to read about when the world would exhaust all resources and discovering that the book never provided a date or even a century, and that was in the early 70s. I recently bought the recent reprint and finding no dates, found a copy of the first edition in a library and still no date. Yet I see comments everywhere about how the book was wrong in failing to predict something that it never predicted, a fact that would be clear if the writer took an hour to find a copy of the book in a library and glanced through it.
We have a problem in our education system. We seem to have teachers who have no idea about science, critical thinking, doing good research, finding the best, meaning original source, of weighing multiple views of the data and competing arguments and theories.
Some suggest that Intelligent Design is a recent theory, yet I am old enough to know that Erich von Daniken made the same argument 30 years ago, but his intelligence was space aliens. Isn’t ironic that the Fox Network’s most scientically accurate programs were produced by Chris Carter – at least he cleverly wove fact into enjoyable fiction.
I don’t know, but somehow I think us aging hippies screwed up somewhere over the past three decades, failing to keep alive and pass on the ability to question everything?
In addition to #56, the ice core data mentioned in https://www.realclimate.org/index.php?p=13 reveal that a decrease in temperature (some 8 K) in the previous interglacial-glacial transition is followed by a CO2 decrease of ~50 ppmv, many thousands of years later. The decrease in CO2 levels had no measurable influence on temperature. This was disputed, by Severinghaus, pointing to Cuffey and Vimeux, which corrected the deuterium data used as temperature proxy. But the correction doesn’t change the timing of the temperature/CO2 changes, only the amplitude. That can be seen in later work from Jouzel and Vimeux at http://www.ipsl.jussieu.fr/GLACIO/hoffmann/Texts/jouzelJGR2003.pdf see the last page, where the deuterium and corrected temperature are presented. Temperature decreased in the period 120-110 ky BP, CO2 levels decreased 111-104 ky BP, taken from the Vostok ice core data, see http://home.scarlet.be/~ping5859/co2_temp_ice.html .
Consequently, CO2 has little influence on temperature in the 50 ppmv range, far less than current models implement (0.3-1 K).
That a CO2 doubling causes 4 W/m2 extra heat retention maybe right theoretically, but several other sources find a much lower sensitivity of our climate to forcings, see: http://www.warwickhughes.com/hoyt/climate-change.htm
And climate models understimate natural climate responses, which seems to be largely negative (underestimated in most models). The higher sea surface temperatures in the tropics (~0.85 K/decade in recent decades) have lead to an increase in LW (infrared) radiation, and a loss to space of some 3 W/m2 all over the tropics (50% of the surface), which more than halves the – theoretical – global influence (~2.4 W/m2) of all extra GHGs together since the start of the industrial revolution. See the papers of Wielicki http://www.atmos.ucla.edu/csrl/publications/pub_exchange/Wielicki_et_al_2002.pdf and of Chen e.a. http://pubs.giss.nasa.gov/docs/2002/2002_ChenCarlsonD.pdf
Maybe some downward “projections” of the climate models should be included in the range…
Response: Nobody is claiming that CO2 is the only thing affecting climate. Especially at the regional scale, ocean and atmospheric circulation changes are clearly also important. For small changes in CO2, the tendency will be small and potentially difficult to see among the other effects – it does not mean there is no effect. The climate sensitivity (the global mean surface temperature change in response to a doubling of CO2) is estimated from models to be around 3 deg C (+/- 1 deg). This is also supported by the paleo-data. At the last glacial maximum (20,000 yrs ago), forcings by ice sheets, vegetation, greenhouse gases and dust loading are estimated to be around -7W/m2, and that sustained a climate 5 to 6 degrees cooler than present. This is consistent with the model estimates, and provides a severe test for those who would argue that the sensitivity is much less (say <1 deg C). If sensitivity is that low, then the forcing at the LGM needs to have been more like -20 to -25 W/m2 – and where would that come from?
Tropical variability does appear to be greater in the real world than in the models, and that is the subject of significant current research into the satellite record and the models, however, there is no indication that this necessarily indicates a smaller sensitivity. And, as you well know, the reason why there are no ‘downward’ projections is that the forcings continue to increase. – gavin
Re the 1940-1970 cooling: I’d be rather interested in a model of the interaction between atomic explosion and cliamte. During that period there were almost 500 nuclear tests (in the atmosphere). A severe inpute of particulate in the stratosphere definitively modified the climate patterns..
[Response: this isn’t my strong point, but AFAIK no-one within the climatological community considers them significant. I suspect that their input into the stratosphere was quite small, though I have no numbers to back this up – William]
From post 67, Gavin says:
> Response: I am actually one of those scientists that spend almost all > their time (when not answering needlessly aggressive posts like this) > comparing models with data and seeing if my ideas fit both. I …
Gavin: Your gripe that John’s post was “needlessly aggressive” appears a bit sanctimonious given your “needlessly aggressive” comments only a few posts earlier (post 51):
> Response: Let me try again to make my position clear, since you
> obviously failed to grasp the point earlier. I (and other
> climatologists) are not in the business of fortune-telling. I do not
> know what CH4 or CO2 levels will be like in 100 years time. This may
> come as a shock to you, but it really shouldn’t….
Response: Ah, but there it was needed…. ;) – gavin
It might be interesting to some readers of this site to know that Crichton’s comparison of global climate change theory to eugenics in Appendix I of his novel was adapted without attribution from an essay by Richard Lindzen, “Science and Politics: Global Warming and Eugenics,” which appeared in R.W. Hahn, Ed., Risks, Costs, and Lives Saved, (American Enterprise Institute, 1996). Lindzen kindly makes a PDF copy available on his web site, http://www-eaps.mit.edu/faculty/lindzen/180_Eugenics.pdf.
Crichton lists several other Lindzen publications in his bibliography, but omits this one, which mileads the reader into thinking that the ideas in this appendix are Crichton’s own. Where I teach, we disapprove of this sort of thing, even in works of fiction.
I just read the book.
It was really awful, on so many levels, but in particular it showed so little understanding of the nature of prediction. Post #69 posits that MC actually understands that prediction involves confidence band, but that idea is no where present in the book. As already noted above, neither was the idea that many variables may influence a single outcome. In fact models and scientists are completely absent.
The social science is also awful. Not that this board cares, but the hypothesis that society needs demons in the forest and the other that ordinary people are generally poor at estimating risk say nothing about whether or not there is actually danger.
The funniest part–except for the plot, of course– is where the good guy characters say that in the future they will use only data, not hypotheses.
Response to 66:
Baloney. Arrogant pollution apologists like you think they have the right to impose their unwanted emissions on others.
This is a “Big Lie.” Banning DDT in the U.S. didn’t cause millions of deaths in the Third World. Some countries still produce DDT. Why you think U.S. environmental law holds in foreign countries is unclear.
If you can keep your pollution on your property, you’ll get no argument from me. I’d love nothing more than to see anti-enviros suck up all the toxic pollution they can get. When you start polluting the commons, you should expect limits on your “freedom.”
Why anybody would defend the “freedom” to pollute is beyond me.
[This comment edited to avoid off-topic wars – William, 2005/01/05]
A point Crichton raises that, in my opinion, merits serious discussion is the cost/benefits analysis of environmnental regulation, combined with the principle of uncertainty relating to unintended consequences. In an interview of Crichton published in a U.K. newspaper a few days ago, he stated that he might endorse the Kyoto Treaty, or something similar, 10 years from now IF the science, at that point, more strongly supports the global warming theory than he believes it does now. The Kyoto Treaty, if ratified, will effect a major change in the way we do business, particularly in the U.S. The compliance costs and related economic costs, e.g, lost opportunities, will be staggering. I think all Crichton is saying is that we need to be very, very sure we are right about global warming before we expose our economy to the potential disruption the Kyoto treaty would entail. I agree with him 100% that you cannot divorce science from politics at this level. There’s no free lunch.
Response: Had Crichton simply used this economic argument, I would not have complained about his use of science. Whether Kyoto is or isn’t cost effective is irrelevent to the scientific understanding of climate change. As stated in the blog description, no digressions into the economics or politics will be entertained here. – gavin
In response to #73, Gavin responded that it is not only CO2 that is necessary to change climate. That is right. But one can find similar results of the models by adjusting a few parameters opposite of each other. E.g. there is an offset between GHG forcing and sulphate aerosol forcing. Higher estimates of GHG influences need to be compensated with higher influences of aerosols to fit especially the 1945-1975 period trend. The same for solar influences. If solar is increased by feedbacks (like cloud cover), that will give the same fit of past temperature data at the cost of combined GHG+aerosol.
The Hadley Centre has done some model experiments with 10x solar and 5x volcanic to test their influence. See: http://climate.envsci.rutgers.edu/pdf/StottEtAl.pdf
The best fit was with 2x solar according to Hoyt & Schatten, at the cost of 20% of GHG influence. But that was within the constraints of the model (no change in aerosol influence, lack of solar stratospheric influences, no influence of solar on cloud cover…).
As already said, there are a lot of indications that GHG influences are overestimated in current models (see discussion #10 and #11 of https://www.realclimate.org/index.php?p=22 ), not at least as the influence of sulphate aerosols are not measurable where the largest cooling according to the models should be seen. See: http://home.scarlet.be/~ping5859/aerosols.html
At the other side, if the influence of solar cycle(s) on cloud cover is real (no matter what mechanism is involved), then the initial variation in insolation (as incorporated in current models) is increased by a factor 4-5. The change in cloud cover between the Maunder Minimum (Little Ice Age) and today would make a difference of ~7 W/m2, pretty close to the 7 W/m2 which is lacking at the depth of the previous glacial…
I have a proposal. Make a few runs of the HADcm3 climate model around a 5 times increased solar (according to Hoyt & Schatten) and a 5 times reduced GHG&aerosol influence set for the period 1860-2000. Although not perfect (the influence of solar on the stratosphere, cloud cover, jet stream position,… are poorly described in the model), it will make clear that other combinations than mainly GHGs describe the far and near past as good (or not). Of course, that costs a lot of time and money if done on the mainframes. But climateprediction.net offers an inexpensive possibility to run the model sets in the background on several home computers worldwide at once (actually, a HADsm3 model set is running on my PC). The answer may take several months, but as the CO2 doubling is not yet for tomorrow…
Dear Gavin:
John Brockman has done us all the good service of posing, as an _ Edge _ question, what is it that we believe that we cannot prove?
To avoid Mike Crichton declaring a Scotch Verdict, let me therefore raise a matter that you are competent to answer in that spirit.
GCM’s on a global or pixel scale, operate of necessity using mainly time averaged values of dynamic variables-in the case, for example of a 1-D model, diurnal variations are approximated by average values of insolation; likewise cloud cover is smoothed to a representative number and homogeneous average precipitation replaces the squally reality of showers and rain bands.
So we are left with little sense of how much some ‘average’ macrovariables like albedo, vary day to day and hour by hour as clouds come and go and land use and natural cover vary
Can you edify us on, basically, what the limits of dayside albedo are, both in the visible and IR?
[Response: you seem to be suggesting that GCMs use diurnally averaged insolation. But they don’t. Hadcm3 (in its standard configuration) does the (expensive) shortwave calculations every 3 hours and interpolates between. I think the longwave is done every half hour. Clouds vary on the half-hour timestep. These numbers would be different for different GCMs. Perhaps we need a primer post on what-are-GCMs? – William]
Thank you all for the (so far) interesting discussion. I have a question regarding an item mentioned by Crichton’s book that hasn’t been discussed so far.
Crichton describes a report issued by the IPCC in the 90’s where bureacrats edited the original draft written by scientists to imply that global warming is occurring. If I remember correctly the scientists claimed in the original draft that they couldn’t be sure to what degree global warming was occurring. Crichton claims that this was later changed to something like “The balance of evidence suggests a discernible human influence on global climate”. Did IPCC bureacrats actually do this? Internet links to the various report drafts as well as the final report would be appreciated.
[Response: Its a fairly standard skeptic claim, thought I can’t bring an example to hand for the moment. You won’t find the draft reports, of course, but the final report is at http://www.ipcc.ch. The claim is false, of course. The skeptics have a hard time arguing with the science, so they devolve to arguing about the process. The kernel-of-truth involved is that the summary-for-policymakers bit is negotiated. Kevin Trenberth, who was involved, has a nice article about the process at http://www.cgd.ucar.edu/cas/GLOB_CHANGE/ipcc2001.html. Its for the TAR not the SAR, but you’ll get some idea. You say “IPCC bureaucrats”: this is probably an error – William]
Regarding comment 83:
Here is an interesting set of letters regarding the changes, and defending the IPCC and Ben Santer:
http://www.ucar.edu/communications/quarterly/summer96/insert.html
The charges were made by Fredrick Sietz, who is not a climate scientist and took no part in the IPCC, and published in the Wall Street Journal. According to the letters the changes were all within the IPCC guidelines. There was also a report on the controversy in Physics Today ( “Attacks on IPCC Report Heat Controversy Over Global Warming”, Toni Feder, Physics Today, August 1996, pp 55-57).
[Response: thank you. Thats a very useful link – William]
After perusing the links it appears that there were indeed changes made to the report, that those final changes were considered to be part of the scientific review process, and that IPCC guidelines were followed. However there are a few things about this episode that concern me. Here is a quote from one of the letters found at the link: http://www.ucar.edu/communications/quarterly/summer96/insert.html
“In the weeks before the Madrid meeting, many additional review comments on the October draft were received. For instance, the United States government in submitting their points for review, commented on ‘several inconsistencies’ and stated ‘it is essential that the chapters not be finalized prior to the completion of the discussions at the IPCC Plenary in Madrid, and that the chapter authors be prevailed upon to modify their text in an appropriate manner following discussion in Madrid.’
A substantial part of the Madrid meeting was devoted to scientific presentation and discussion regarding the extent to which anthropogenic climate change has been detected in climate observations. Further review comments from experts and government delegates were received and the Lead Authors were formally asked to consider modifications for improvement. The Plenary meeting finally “accepted” Chapter 8 (the chapter Mr. Seitz attacks) and the other ten chapters of the report, subject to the Lead Authors revising them in the light of the Madrid discussions. The Plenary meeting was, in fact, the final part of the very comprehensive and thorough IPCC process of peer review.”
The U.S. government is asking that “chapter authors be prevailed upon to modify their text in an appropriate manner following discussion in Madrid.”? In the second paragraph it says “Further review comments from experts and government delegates were received and the Lead Authors were formally asked to consider modifications for improvement.”. Why are the U.S. government or government delegates asking for modifications to what is a scientific report?
Although I haven’t been able to find earlier drafts of the report on the internet I was able to locate the following page http://www.sepp.org/ipcccont/Item03.htm from SEPP (apparently an environmental skeptics organization). This page purports to show what was removed, changed and added to chapter 8 of the report. Some of the modifications certainly appear to change the character of the scientific assessment. Can anyone confirm whether this is an accurate representation of the changes made?
[Response: SEPP is indeed highly skeptical, though slightly questionably an “organisation” – it is essentially the project of Fred Singer. Whether what is on that page is reliable is unknown – it has no indication of its source. The changes indicated do not appear to alter the sense significantly, especially when read in conjunction with the full text, which is of course much larger. In accordance with the charter of RealClimate, we’d rather be discussing the *science* rather than textual criticism – William]
My comment on Crichton’s book about global warmings,
“Michael Crichton’s Deep Lobbying”
is on Harvey Wasserman’s web site but kind of hard to find.
http://WWW.freepress.org
then click on “departments” and under “reviews”, there it is.
Gene Coyle
Regarding his stance on CO2 levels and warming, you’re arguing the same thing he is. In the author’s notes, he says that (in fact, you quote him later.) His claim is that we don’t understand climate or weather well enough to attribute the change to a single source, so getting worked up over the Greenhouse Effect is a scam from activists, not scientists.
Regarding uses of temperature data, your argument falls in line with his. You forget that this is a novel, not a text; the legal teams makes your argument successfully. Likewise, certain characters make off-hand remarks (such as the “There’s your global warming” comment made by Sanjong, an agent, not a scientist.) It’s obvious that Kenner is the voice of Crichton, and it’s not Kenner that makes the comment. It’s a novel. Characters are allowed to be wrong.
As far as the Hansen study is concerned, why don’t you post the data on the total change compared to the predicted total change? Likewise, post the graph of the Hansen study error every year. Those two datasets offer much better evidence than the graph you presented. (NOTE: I don’t know what that data looks like. However, I feel that if you’re going to make the argument, you should use the relevent information, and my data/graphs are more relevent.)
As far as the quotes on 315 and 563: The quote on 315 is essentially correct. In the 1970s, climate scientists believed an ice age is coming, just as they believe now that an ice age is coming. The Earth operates cyclically and it’s only a matter of time until the next Ice Age cycles comes around. This is the point conveyed on 563 (admittedly, the point of 315 was to illustrate the political and social appeal of global warming.) 315 is somewhat of an error, but 563 absolves it.
Regarding the UHIE, I believe you’re, again, barking up the wrong tree. The point he made regarding UHIE was that the corrections are a matter of ethics and an easy way to massage data. Admittedly, I haven’t read the Parker article (and cannot because it’s not publicly available), but the bibliography contains sources supporting it. At best, this is a debated topic and Crichton only pointed out the possibility of dishonesty.
For the satellites, where’s the data on the long-term trend? I don’t have it, but if you’re going to make that argument, you need to have that data, too.
Response: Try White et al (2004) and references in there. I don’t know of a online dataset – gavin
In the author’s message, Crichton was referring to the cause of temperature rise being urban growth more than greenhouse CO2. He didn’t offer any support for this claim, so I doubt anyone would put much faith in it, anyways.
Regarding eugenics, you forgot the overwhelming similarity that they were both widespread, media-friendly, commonly-believed “facts” that proved to be false (whether or not Global Warming is false is obviously debatable, but he’s operating with that disclaimer when he makes the comparison, and thus it is necessary to operate under it when disputing his claims.) His point is that, if Global Warming is false, (as he is assuming it is–which you must honor when considering his comparison), it is a modern-day eugenics. Eugenics lead to widespread ethnic cleansing (we call it the Holocaust), and he just wrote a book about eco-minded terrorists; both topics can be taken to a dangerous extreme, and he is just cautioning those of blind faith that the proof of foundation-sponsored science has been entirely wrong in the past, and has led to horrible atrocities. It’s a warning, not an accusation.
re: comment 73 response (by Ferdinand), “The climate sensitivity (the global mean surface temperature change in response to a doubling of CO2) is estimated from models to be around 3 deg C (+/- 1 deg). This is also supported by the paleo-data. At the last glacial maximum (20,000 yrs ago), forcings by ice sheets, vegetation, greenhouse gases and dust loading are estimated to be around -7W/m2, and that sustained a climate 5 to 6 degrees cooler than present.”
1) One could argue your statement is not “conclusively supported by the paleo-data” — one need only argue that C02 levels are a lagging result (rather than leading indicator) of temp change, and your 20,000 year ago glacial maximum as GHG evidence becomes tenuous at best. In fact some studies purport such a lag in CO2 levels, some by well over a century.
Response: The LGM can be considered roughly stable over a two thousand year period. Thus it must have been in radiative quasi-equilibrium. Ice sheet extent and GHG levels were stable for almost all of this period, thus small lags of a century or two are irrelevent. That’s why I highlighted this particular example.
2) Who is (are) the astro-physicist(s) of your advisory team? What are the teams AGW concensus comments about solar output factors, which according to some studies (including Max Planck Institute) were at an 8000 year high in 2001?
Response: Solar forcing over the direct observational period (since 1979) has been measured to be small. Going back further, proxy reconstructions must be made but these are quite uncertain. The study you reference (Solanki et al, 2001) was indeed quite interesting, but unfortunately does not provide solid evidence of what their sunspot record actually implies for long term climate. However, they go out of their way to note that “we stress that solar variability is unlikely to be the prime cause of the strong warming during the last three decades”.
3) How are the Paleoclimatic proxy records of the Sargasso Sea factored into your advisory teams AGW position? For instance, Keigwin’s NOV’96 Science paper which showed 4-5 occurences higher sustained sea-surface temperatures oscillations over 3
milleniums of core sample averages, vs. our last 100+ years? His data also had obvious evidence of the Medieval Warming Period and Little Ice Age — something that Mann-Bradley-Hughes missed in their 1998-9 work, and again with Mann in 2001?
Response: One record does not a global Medieval warm period make. ‘Global’ is the key word there. It turns out that many of the so-called ‘MWP’s seen in seperate records actually occur at different times, and so would not show up in the global mean. I recommend reading the Bradley et al (2003) Science Perspective dealing with this matter. – gavin
See also our discussion of “Hockey Stick myth #2”, and the section “Was there a “Little Ice Age” and a “Medieval Warm Period” in chapter 2 of the 2001 IPCC report which specifically discussed the Keigwin (1996) record you mention and its likely reflection, at least in part, of changes in the North Atlantic Oscillation in past centuries. Changes in the NAO appear to play a prominent role in the spatial pattern of climate change in past centuries (see e.g. the review paper: Schmidt, G.A., D.T. Shindell, R.L. Miller, M.E. Mann, and D. Rind 2004. General circulation modelling of Holocene climate variability. Quaternary Sci. Rev., 23, 2167-2181, doi:10.1016. ). Regional influences due to changes in the NAO and the El Nino/Southern Oscillation in past centuries complicate the relationship between regional and truly hemispheric or global temperature estimates. For precisely this reason, the numerous proxy and model-based estimates of the variations in the average temperature of the Northern Hemisphere (not just just the Mann et al reconstruction, as implied by your comment) show far more modest temperature changes than those typically interpreted from specific proxy records from any one region. -mike
The tone of the article and especially of the comments printed above gives us a perfect example of what Crichton is writing above, of chutzpa and arrogance of those presenting the global warming results to the general public and their coldwar like/zealous approach to the truth (it is war an anybody who mentions the facts that might be interpreted to help the enemy should be silenced).
Many of those commenting admit openly to not reading even the 5 pages authors message in the end of this book but still feel free to blast him as a infidel, heretic and serving big industry inetersts. It reminds me so much the atmosphera of intelectual “freedom” in the stalist Soviet Union.
Main point i like in the Crichton book is that climate sience is very complicated and not well understood. Even author of the above post in trying to explain the reverse of the global warming trend in years 40-70 explains it by some other not well understood trends. Can we say that such trends will not appear in future? Can we really be sure what will be the response of the whole global environment to current changes? What about his point that in 70 ties the “consensus” was that we see the begining of cooling and the new ice age.
[Response: that too is wrong. A post on this is in draft; in the meantime you can try http://www.wmconnolley.org.uk/sci/iceage/ – William]
I do believe that even if we feel that it is better to err on the side of too much fear as is common between concerned scientist we do have to admit this error if we want to have credibility.
I think that his comments about eugenics are remarkable and should force us all to stand aside from our rightiousness and try to see the issue as people may see it in 100 years. Too much agreement (like those 100% of 765 papers) sounds very suspicious and Orwelian.
In addition to comment #89 by John McCall,
There is – again – a lag between CO2/CH4 changes and temperatures at the end of the last ice age. While in the upswing difficult to see (~1,000 years on the 5,000 years increase in temperature), at the end of the first warming step, there is a sudden increase in temperature and in CH4 (methane) concentrations (melting methane hydrates, permafrost, ice free land?). That is followed by a decrease in temperature. When CH4 levels fall, some 2,000 years later, temperature starts to rise…
See: http://home.scarlet.be/~ping5859/end_glaciation.html
[Response: What is your point here? What you are seeing is a reflection of northern hemisphere variability (Bolling-Allerod, Pre-boreal period, Younger Dryas etc.) which impacts methane sources in northern wetlands. This methane is relatively well mixed (which is why it can be used to cross date the Greenland and Antarctic ice core records). What is difficult about accepting that yes, climate affects CO2 and CH4, and that yes, CH4 and CO2 in turn affect climate? -gavin]
In the article, you say
Had the characters visited the nearby station of Santa Barbara Aeropuerto, the poster
on the wall would have shown a positive trend
I know it’s a bit sad but I thought I’d have a look but I can’t find the Santa Barbara
you refer to in GISTEMP. I can find 2 Santa Barbara stations but they are both in the NH
so neither of them can be the one you mean. They are slightly interesting, though
There’s Santa Barbara/FAA Airport here
http://www.giss.nasa.gov/cgi-bin/update/gistemp/show_station.py?id=425746060010&data_set=1&num_neighbors=1
which doesn’t show any warming trend – then there’s Santa Barbara here
http://www.giss.nasa.gov/cgi-bin/update/gistemp/show_station.py?id=425723910030&data_set=1&num_neighbors=1
which does – but seems a bit flat since around 1980 (apart from around 1997/98)
As the stations appear to be located at the same longitude/latitude – do we have a case of UHI? We could
start a whole new study on Santa Barbara.
[Response: Arrghhh! My bad! It is Santa Cruz Aeropuerto. I always get these two mixed up (though usually in a Californian context!). – gavin]
I am in general sympathy with your point-of-view, and I’d like to thank you for the judicious and reasonable tack you take here.
But I found Crichton’s book to be rather more interesting than you did, perhaps because I know so much less about the technicalia of global warming and climate modelling than you seem to.
Your first point beginning “The first set of comments relate to the attribution of the recent warming trend to increasing CO2. . . .” seems to me to be something that Crichton would agree with. At the end of this paragraph you acknowledge that the state of historical climate science is still working on “best guesses.” Crichton’s point is that we oughtn’t get too terribly worked up or run off and do too much of anything on the basis of best guesses. Guesses based on assumptions that may very well reflect the biases of the people making them.
Crichton may well be wrong, but it seems to me to boil down to a political question, not a scientific one. You can say climate modelling is better than educated guessing, or “land use change globally is a cooling effect” but is there proof of either these points? If not then you are perpetuating precisely the thing Crichton quite rightly complains about: when scientists get into political fights, their surmises and guesses quickly transform themselves in facts–facts coming from the mouths of experts.
Sort of reminds me of the CAST numbers–the epidemiological estimates of the numbers of foodborne illness in the US. The “solid numbers”: doctor reports of illnesses were ridiculously low because the diseases went underrecognized and unreported. The initial estimates (“the Cast numbers”)from experts turned out to be far too high. Why?
It wasn’t that the models the scientists had built were crap. it was because the models depended on numeric assumptions that could have very big effects on the final estimates; and the scientists tended to make assumptions that reassured them of the importance of their field of study.
When active surveying was done, and good information for estimates was gathered, it turned out that “best guesses” for the occurance of foodborne illness fell precipitously. But not before the bigger estimates had not already been used over and over agin in the press and not before a backlash set in against the food safety cassandras.
So what stage are the global warming folks at? CAST number stage or fairly solid, testable model stage?
I haven’t seen anything that helps me decide. I see a lot of “I don’t like Michael Crichton” stuff, but frankly I don’t care about that. I care about global warming, and I am not particular willing to accept it as an article of faith.
Of course, there’s lots of dumbass stuff in the Crichton book, but I still find myself skeptical of Crichton’s chosen enemies.
Any help for the skeptical layperson? Where to start?
–eric