Comments Jim Clarke has made

  • Back to the main point

    The original article above boasts that no one has found any significant flaws in the most recent IPCC publications, giving the impression that the IPCC is correct about climate change.  Not true!  The impression is based on the assumption that the theory is entirely correct to begin with.  William Briggs, statistician, addresses this in a recent blog entry here:

    http://wmbriggs.com/blog/2008/02/18/statistics-dirtiest-s ...

    The whole article is worth a read, but here is the most significant paragraph relating to the subject at hand:

    "It is important to understand that all results (like saying "statistically significant", computing p-values, confidence or credible intervals) are conditional on the model chosen being true. Since it is rarely certain that the model used was true, the eventual results are stated with a certainty that is too strong. As an example, suppose your statistical model allowed you to say that a certain proposition was true "at the 90% level." But if you are only, say, 50% sure that the model you used is the correct one, then your proposition is only true "at the 45% level" not at the 90% level, which is, of course, an entirely different conclusion. And if you have no idea how certain your model is, then it follows that you have no idea how certain your proposition is. To emphasize: the uncertainty in choosing the model is almost never taken into consideration."

    The statements in the WGI report are 'bulletproof' only if you start with the ridicules assumption that all of the assumptions going into the report are absolutely correct and the model is `true'!  Mr. Dessler is really boasting that they didn't make any grammatical, clerical, math or continuity errors this time around, which doesn't lend any weight at all to the strength of the AGW argument!  Indeed, the statement that "...essentially none of the IPCC documents produced over the last 18 years has been found to contain any substantive errors" is an internal argument.  It is essentially proclaiming:  "Assuming our model is correct...we have not made any errors!"

    Skeptics are, and have always been arguing that the AGW model is not correct and that many of the assumptions that go into the model are inaccurate or just wrong.  Not only are their errors of attribution (providing values that are not accurate) there are more errors of attrition.  The model does not contain a significant amount of what is actually taking place in the real world.  It is only by ignoring all of these things that supporters like Mr. Dessler can proclaim that the reports contain no substantive errors.

    Furthermore, the main selling point of the WGI report, in order to be statistically and scientifically accurate, should read "Assuming our theory and model of climate change are correct, and all the assumptions that go into that model are correct despite the large gaps in our understanding of various processes, we have a 90% confidence that our conclusions are true."  This accurate statement is considerably weaker than the one being foisted on politicians and the public.   While some may understand the implied assumptions, must don't and are being given a false impression of the accuracy of climate change science.   This will result in very poor decisions, causing considerable problems while providing no discernable benefits.
    On The fourth IPCC report is still going strong a year later posted 1 year, 9 months ago 65 Responses

  • Do we really want to do this?

    In answer to Max's question:  Yes, there are some who want to decrease the standard of living of every man, women and child on the planet in the name of a climate crisis.  They are in the minority, so they must exaggerate the threat to get their way.  Of course, the 'exaggeration of threat' is the rational behind every organized act of injustice and evil in the world over the last 100 years and beyond.  They all start with a noble cause and then exaggerate the threat to that noble cause.

    My litmus test for the legitimacy of any organization or movement is whether or not they are exaggerating a threat.  Certainly those calling for immediate action on climate change are hyperbole wizards, using only the most dire scenarios, no matter how unlikely, to further their cause.

    (Note to Mr. Dessler:  I am not talking about the IPCC here, but about those calling for immediate action. This includes environmental groups, Al Gore, James Hansen and the Chairman of the IPCC, among many others.  All use hyperbole and act as if it is the mean!)
    On The fourth IPCC report is still going strong a year later posted 1 year, 9 months ago 65 Responses

  • Many thoughts

    Max,

    Thank you for your posts. Your explanation of the hockey stick as a key political weapon was spot on.  Still, I think it is a case of sour grapes when scientists say it was never really important to begin with.  All theories must be verified by real world evidence to become valid.  The hockey stick was presented as real world evidence to help verify that much of the recent warming was man-made and that the AGW theory was correct.  Without it, what physical evidence do they have that the current warming is primarily human induced.  If warm periods of similar magnitude happened quite naturally in the past, why is this warm period decidedly `unnatural'?  (Please, no arguments about the rate of change here.  The rate of change during the first part of the 20th century is similar to the last part, and we have no idea about rates of change hundreds and thousands of years ago, as proxy records do not sufficient resolution to determine such things.)
    I also agree that in science, the onus of proof falls on the shoulders of those purposing the theory.  If scientists claim to be able to produce cold fusion, it is up to them to prove it.  It is not up to the skeptics to produce their own cold fusion in a different way!
    Still, many skeptical climatologists have a theory of climate change that depends more on pattern recognition than number crunching.  (Computers are notoriously bad at pattern recognition, although they are getting better.)  They have used this theory to predict a period of global cooling beginning in the early 21st century.  Current observations are more in line with this theory than with the AGW theory.

    Christopher,

    You can stare at the ice core graphs and draw your on conclusions if you want, but I was relying on the conclusions drawn by the peer reviewed studies done on the ice core samples.  These studies conclude that there is generally a lag of about 800 to 1,000 years between increasing temperatures and increasing atmospheric CO2.  I wasn't telling half of the story, I was just relying on the conclusions of the studies.  

    Interestingly, there is also a lag when the temperatures are decreasing.  This means that for any given temperature X, the atmospheric concentration of CO2 was usually less when temperatures where warming through X and greater when temperatures where cooling through X!  From this, one can conclude that higher concentrations of atmospheric CO2 cause cooling, or that CO2 is not a large factor in determining global temperature and is generally overridden by other factors.  Since the former explanation makes no physical sense, I prefer the latter.

    CCE,

    As I mentioned before, the sun heats the surface, not the atmosphere.  Urban areas are warmer than surrounding rural areas at night because of the solar energy that is released from paved surfaces after dark.  A solar heated surface results in higher nighttime low temperatures; similar to what one would expect with increasing CO2.  Both solar and CO2 would lead to indistinguishable results concerning nighttime lows.

    Measuring climate sensitivity of any one variable is very tricky.  One must have a good understanding of all the other variables involved.  Ignoring solar variables in the long term and ocean cycles in the short term is hardly and example of a good understanding of the other variables.  Admitting that you really don't know the effect of clouds and the broader water-cycle is also admitting that your estimate of climate sensitivity to increasing greenhouse gases is little more than a guess!

    In order to lend weight to that guess one most show how the real world is and always has behaved just as the guess would indicate.  This brings us back to my analogy of Cinderalla's step-sisters trying to shove their foot in the glass slipper.  They may successfully get a few toes in, but the more they try, the more obvious it becomes that the foot does not fit!  Even sprinkling magical aerosols (quantity and effect unknown) doesn't make the slipper go on any easier.

    The real world is just not confirming the IPCC guess of climate sensitivity to increasing greenhouse gases.  The recent lack of global warming and initial evidence of a cooling trend could be aberrations, but they do not lend weight to the AGW argument.  The fact that recent trends are precisely what skeptical climatologist have expected, does lend weight to their argument.  

    Right now, the real-world `climate momentum' is with the skeptics!On The fourth IPCC report is still going strong a year later posted 1 year, 9 months ago 65 Responses

  • Other Matters

    CCE,

    60 years ago, the atmosphere cooled just as humans were really cranking up their CO2 emissions.  It happened quickly and in both hemispheres.  The IPCC blames aerosols, which makes no sense since aerosols where confined generally to the northern hemisphere and there was no step change in aerosols to match the change in temperature.  For the next 30 years, the planet did not warm, despite ever increasing CO2.  Suddenly, in the late 1970s, the temperature began to rise.  Now, thirty years later, the planet has stopped warming and there is growing evidence that it may be cooling.  All of this precisely matches the PDO and has almost no correlation with increasing CO2, other than some curve fitting in the 80s and 90s!

    You admit that ENSO events have year to year impacts on global temperature.  It has been shown that the PDO strongly impacts ENSO events, with more El Ninos in the warm phase and more La Ninas in the cold phase.  So why do you close your eyes to the possibility that the PDO has a significant impact on global temperature over multiple decades?  It appears to be about 0.3 degrees C, accounting for nearly half of the warming of the 20th Century.  (The Century began at the bottom of the cool phase and ended at the top of the warm phase).

    On solar...the atmosphere is generally transparent to most of the solar energy reaching the planet.  Unlike increasing CO2 which initially causes an increase in the kinetic energy of molecules in the atmosphere (warms the air), the solar changes would first be felt in the oceans, with the additional energy very gradually dispersing into the atmosphere as regulated by the oceans.  One would not expect noticeable changes with the 11-year sunspot cycle, but would likely detect gradual changes over several solar cycles of increasing or decreasing activity, all else being equal.

    You state the direct forcing of CO2 as if it where a known fact.  It is not, but is generally agreed to be in a certain range.  You present the water vapor feedback as if it is well understood and quantified.  It is not.  Much of what the IPCC presents as speculation and hypothesis is perceived as fact.  Again, it is not me that is misrepresenting the IPCC.

    Christopher,

    The ice cores reveal that temperature increases caused CO2 increases.  They also reveal that significant global cooling has always started when CO2 levels were relatively high, making it impossible for CO2 to be the dominant driver of global temperature.  Certainly CO2 has an effect, but there is nothing in the ice cores that indicates it is a dominating effect.  Quite the contrary!

    Also, current global temperature is below the minimum IPCC scenario, no matter which data base you choose.  Global sea ice did take a bit of a dip last year, but is now trending pretty close to the average for the last 29 years.  Claims that everything is happening faster than the models predicted are simply fairy tales.  While there may be a few small regions that have experienced significant warming, most of the planet is not cooperating with the dire predictions of the AGW theory.  Areas that have warmed the most are now showing cooling trends!

    All that we observe is precisely what would be expected if natural cycles still dominated climate change.  

    Watching AGW crisis supporters trying to force the observations to fit their theory is like watching Cinderella's nasty step-sisters trying to force their foot into the glass slipper.  It is getting embarrassing!On The fourth IPCC report is still going strong a year later posted 1 year, 9 months ago 65 Responses

  • Jumping to conclusions

    Mr. Dressler,

    Science indicates that, all else being equal, increasing CO2 will tend to warm the atmosphere.  The amount of direct warming from a doubling of CO2 on a cloudless Earth has been estimated in the peer reviewed literature to be around 0.8 to 1.6 degrees C (as I recall).  Add in the reflectivity of clouds and the number drops.  This direct forcing is not significant enough to produce a climate change crisis.  I believe that the IPCC agrees with this and also agrees that 2+2=4.  I am not saying anything different or mischaracterizing what the IPCC says.

    The IPCC makes an argument that there are positive feedbacks that multiply the CO2 effect.  While there is some evidence for positive feedbacks, there is also evidence for negative feedbacks, which the IPCC also tends to ignore.  Others have provided evidence in the peer reviewed literature that ocean cycles, solar activity and land use changes have played a roll in warming over the last 100 years.  Any validity to these arguments reduces the actual affect of increasing CO2.  Herein lies the debate.

    "There's no evidence in the IPCC that CO2 is a significant climate forcer."  

    Evidence would imply verification with the real world.  The IPCC presents evidence of warming, but does not demonstrate how CO2 explains the warming better than natural cycles in the oceans and sun, and/or land use changes.  One does not verify a theory by ignoring the other theories that fit the observations better.  I believe religions are particularly good at such machinations, not science.

    For those of you who say that the Hockey Stick argument is irrelevant...nonsense!  It is crucial.  The way the IPCC attempts to verify that the recent warming is CO2 induced, is by claiming that there is no significant natural variability in climate.  The hockey stick was supposed to be the physical evidence that supported the theory.  Without the hockey stick, (Or more precisely... if the MWP was as warm as today) the argument that most of the recent warming has been natural remains viable.  

    Those claiming that the Hockey Stick doesn't matter are basically arguing that real world evidence is not required to confirm a theory!  This is hardly scientific behavior.
    On The fourth IPCC report is still going strong a year later posted 1 year, 9 months ago 65 Responses

  • Who is misrepresenting who?

    First of all, everyone needs to be reminded that the IPCC reports are being used as the primary argument for restricting and controlling global energy use to the detriment of every man, women and child on the planet.  I would like to think that those involved would be extra careful in their wording regardless of what the skeptics might say.  If the skeptics are responsible for motivating the authors to produce a better document, then we all should be thanking them, not calling them trolls.

    Those scientists skeptical of a man-made climate crisis are not so much concerned with finding grammatical or minor math errors.  Such trivialities would not invalidate the WGI viewpoint in any way.  The IPCC reports represent one theory of climate change and within the context of that theory, they are reasonable; much like models of Earth-Centered cosmologies where elegant and consistent in themselves.  

    The problem with the IPCC representation of climate change is that it ignores or downplays a great deal of evidence that runs contrary to their theory.  Paleoclimate issues have received the most press, but land use changes, ocean cycles and solar influences are all treated as relatively unimportant, despite a great deal of evidence to the contrary.  Supporters argue that there is no proof that these other factors are 'significant', forgetting that there is also no proof that CO2 is 'significant'.

    Most of the misrepresentation of the IPCC actually goes in the other direction.  All the 'ifs', 'possibles' and 'mays' in the IPCC reports are presented as slam dunks by the media and green organizations.  The cautious, speculative phrases in the original documents become statements of factual doom in our local newspapers, green websites, cable channel specials and ex-vice-presidential slide shows.  These misrepresentations are apparently okay, possibly because they do not undermine the basic world view of the AGW crisis supporters.  Accepting these exaggerations without complaint, however, does undermine their credibility.  

    If skeptics respond to these exaggerated claims, they are accused of misrepresenting the IPCC; while those actually making the `doom-enhanced' statements are not reprimanded in any way!

    Finally, AGW crisis supporters love to write about what crisis skeptics think and why they think it; almost always misrepresenting the skeptical viewpoint.  Mr. Dessler does a fine job of demonstrating this with the post above!
    On The fourth IPCC report is still going strong a year later posted 1 year, 9 months ago 65 Responses