It will go down in history as the biggest joke ever written.

I actually plowed through a bit of the mess but ended up tossing it in the waste bin.  

Texeme.Construct(function(x)=Participation(x))

As Jabailo mentions, to plough through the whole 1600 pages of WG1 alone, apart from WG2 and WG3, is a massive job, and it is not easy to find all the stuff that has been left-out or obfuscated.  Max Manacker has been diligent in this area, and when he returns from his break, perhaps he can comment on this better than most.  

Uh, jabailo, the reason why no self-respectin' scientist will criticize the report is 'cause nearly all of 'em agree with it.  More than 1,000 well-respected scientists got together to write it after all...that's more than have ever written/contributed to any single report...on any issue...ever...in the entire history of humankind.

So you'll forgive me if I don't hold your level of scientific knowledge on the subject as high as I do that of over 1,000 highly-regarded scientists with degrees and awards from almost every prestigious and well-known university and scientific organization.

1.  The Hockey Stick is in AR4, along with a dozen other temperature reconstructions, none of which show a "MWP" warmer than today.
   
2.  The likelihood that today's temperatures are warmer than the last millennium remain >66%, although it has been extended to 1300 years, instead of 1000 years from the TAR.
   
3.  Temperatures in Greenland in the early 20th century were at best the same as they are they today and were the result of decadal changes in ocean circulation, and not representative of global temperature.

No of course not. In Andrew Dessler's universe the Hockey Stick was not obviously and completely debunked, its inner workings shown to be the result of bad statistics, bad math and bad data, a conclusion made by multiple independent investigators.

Back in the real world, Andrew Dessler is simply delusional if he believes that the IPCC's reports contain no errors. All of the multiproxy studies quoted in the latest IPCC report similarly fail statistical tests for significance, and most, if not all, use the Hockey Sticks PC1 or the tainted and unreliable Sheep Mountain bristlecone pine proxy that even the NAS Panel said should be avoided.

But at least as far as delusionalists go, Dessler is one of the happy kinds.

"Subsequent work has carried out very similar analyses with principal components replaced by much simpler methods like simple averaging and has arrived at essentially very similar reconstructions.  So the committee reviewed that and other statistical issues that had been identified in that first analysis and while finding that the issues are real but that they had a minimal effect, not a material effect, on the reconstruction.
"[Mann et al's methods] were all quite reasonable choices.  I think in some cases a lot of subsequent, hard work by others in following up on that have showed that some of those choices could have been made better, but they were quite plausible at the time.  I would not have been embarrassed by that work at the time, had I been involved in it and I certainly saw nothing that spoke to me of any manipulation or anything other than an honest attempt at constructing a data analysis procedure." -- Peter Bloomfield

"I have no cause to think that there was anything inappropriate, professionally." -- Jerry North

This conclusion of the IPCC's Third Report was correct, and was even validated by a National Academy panel (although they use the word "plausible" instead of "likely").  There are great uncertainties and any temperature reconstruction, but the bulk of the evidence makes it more likely than not that today's temperatures are warmer than the MWP.  

At any rate, I thank JohnA for making his comment, because it perfectly represents the way trolls misrepresent the IPCC's reports.  If they honestly represented the IPCC, they wouldn't have anything to complain about.

For instance, concerning their citing of UNPUBLISHED (yes, unpublished) Wahl & Ammann 2006, here is one of many critical expert review comments that were typically ignored by the IPCC mediating authors  (severely limited by space to show them here)

"The statement "Wahl and Ammenn (accepted) demonstrated that this was due to omission by McIntyre and McKitrick [MM03] of several proxy series used by Mann et al (1998)." Is incorrect and should be deleted on factual as well as procedural grounds (see previous comment). In their paper, Wahl and Ammenn state: "In MM03, the authors describe their results as being developed using the MBH reconstruction methodology, albeit with elimination of a large number of proxy data series used by MBH, [Mann et al] especially during the 15th century." There is no such statement in MM03. Quite the opposite. MM03 reported that some proxy series data said to have been used in MBH98 were not actually used. Subsequently, McIntrye and McKitrick filed a Materials Complaint with the journal Nature. In response to this complaint, Mann et al admitted that 35 series [Note; not individual data points but a whole series] said to have been used in MBH98 were not actually used, but claimed that this did not affect the results. Wahl and Ammenn were able to closely reproduce the original reconstruction when all records were included. However, prior to this, McIntyre and McKitrick (2005a, 2005b) also had reproduced MBH98 results using the flawed principle components method. Wahl and Ammenn reproduced McIntrye and McKitrick (2005a, 2005b), and, in the final version of their paper, also reproduced MM's finding that MBH98 failed rsquared verification.
[Jeff Kueter (Reviewer's comment ID #: 137-68)]"

Most of the dismantling of the hockey stick has centred around the treatment of the proxy data, but in addition, there are five (5) separate falsehoods concerning the treatment of the final 50 years.  The most obvious is that whilst the proxy data has a 40-year smoothing filter applied, the instrumental data, (in attention grabbing red), is unsmoothed, and ends with the freak 1998 El Nino spike.  Elsewhere, in the same 2001 report there is a graph of smoothed instrumental temperatures, which clearly shows that the 1988 spike is about 25% over trend, (or was it 40%? I'm not sure now), which makes a huge difference in visual impact by virtue of the sharply climbing curve shape that results.  Clearly, it was a gross exaggeration intended to scare policymakers, and that graph was sprayed everywhere!.  
Again, there is a lack of space to go through the other scientific frauds here, but whatever, the hockey stick was a disgrace to science.

BTW, the inventors of the hockey-stick and their ilk still persist on a hardcore site known as RealClimate, if you are looking for good stirring stuff to feed your addiction.

If you look carefully you can find a pale shadow of the hockeystick buried under some of the spaghetti all with nice pastel colours hard to distinguish.  If you look carefully you will see that Esper and Moberg who come from a diffferent club from the manna crowd show a distinct MWP, and the borehole data in particular shows a strong LIA

2) The likelihood that today's temperatures are warmer than the last millennium remain >66%, although it has been extended to 1300 years, instead of 1000 years from the TAR.

Didn't SPM 2007 give a 90% guess?

3) Temperatures in Greenland in the early 20th century were at best the same as they are they today and were the result of decadal changes in ocean circulation, and not representative of global temperature.

You are talking about complex systems which you do not understand.  Read Chylek's paper more carefully for a start.  Note that increased snowfall above 1500m in Greenland is attributed to Warming.  Note that NASA has reported that most of the recent sea-ice melt has not been a consequence of temperature, but of strong unusual North winds blowing the Ice into warmer oceon currents, and a consequent reduction of perrenial ice etc etc etc
Finally, but still briefly, Chylek showed DATA that identified a warmer period, and Box, less thoroughly, "similar" to today, and that these points, even though known to the chapter authors were NOT MENTIONED OR MEDIATED.
That is poor science, not discussing what you don't want to hear.

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!

"One major error from the First Assessment Report that reverberates to this day, was the use of HH Lamb's temperature reconstruction for Central England to represent "Global Temperature Variations of the last 1000 years."  This was the graph used in "The Great Global Warming Swindle." It's used in Singer and Avery's "Unstoppable Global Warming."  It's used all over the internet by a great variety of skeptics."

The IPCC in its various reports can only use the best available data to hand to demonstarate what those thousands of scientists want to say at the time.

Dr, Andrew Dessler will tell you that the IPCC only uses peer reviewed information, and that the guesses based on these data, cannot be wrong, since they do not cherry-pick.

As for skeptics using very old or historical interest data, it depends on how white they are. A lot of rationalists are grey, and consider their data very carefully

1.  The Hockey Stick is in Chapter 6 of WGI, page 467 along with a dozen newer reconstructions.
   
2.  Your memory is faulty.  The quote is from the NRC panel report.  The other quotes are from the NRC press conference announcing their findings.
   
3.  Wahl and Ammann was published in the November 2007 issue of Climatic Change.
   
4.  None of the statements that you say were "ignored" is in the final version of chapter 6
   
5.  Then you agree that the Hockey Stick is in AR4, was not "expunged," and not a single reconstruction therein shows a MWP warmer than today.
   
6.  AR4's conclusion was that it is >90% probable that most of the warming of the last few decades is anthropogenic.  It is >66% probable that it is warmer now than any time in the last 1300 years.  The TAR concluded that it was >66% probable that it was warmer now than any time in the last 1000 years.  The NRC panel assigned "less confidence" to the same statement, which was their nomenclature for "likely"/66%/or 2:1 odds, the same conclusion of the TAR.
   
7.  We know what the temperature of Greenland was in the early part of the 20th century because we had thermometers there.  It was no warmer than today.
   
8.  There is increased snowfall in the interior of greenland due to increased moisture in the air due to a warmer world, which is expected.  The overall mass balance of Greenland is negative, currently losing approximately 100 Gt of ice per year.
   
9.  The Lamb reconstruction of Central Europe was incorrectly labeled "global temperature variations of the last 1000 years."  It was not.  It was an actual, certifiable error.

plau·si·ble - adjective
1.    having an appearance of truth or reason; seemingly worthy of approval or acceptance; credible; believable: a plausible excuse; a plausible plot.
2.    well-spoken and apparently, but often deceptively, worthy of confidence or trust: a plausible commentator.

Synonyms 1. Plausible, specious describe that which has the appearance of truth but might be deceptive. The person or thing that is plausible strikes the superficial judgment favorably; it may or may not be true: a plausible argument (one that cannot be verified or believed in entirely).

Just like Andrew Dessler being a "plausible commentator"

Mann et al 1999 didn't exactly dance around the bushes on their claims. How "likely" did they really think their result was?

(page 1) [t]he 1990s was the warmest decade, and 1998 the warmest year, at moderately high levels of confidence.

Of course those expressions of confidence turned out to be based on false claims made about Mann's exciting new method.

Oh, and then there's the Wegman Report, which Dessler studiously avoids in favor of the NAS Panel's remarkable ability to speak out of both sides of its mouth.

Here's what North had to say when he's in front of Congress under oath with a TV camera pointed at him:

CHAIRMAN BARTON. I understand that. It looks like my time is expired, so I want to ask one more question. Dr. North, do you dispute the conclusions or the methodology of Dr. Wegman's report?
DR. NORTH. No, we don't. We don't disagree with their criticism. In fact, pretty much the same thing is said in our report. But again, just because the claims are made, doesn't mean they are false.
CHAIRMAN BARTON. I understand that you can have the right conclusion and that it not be-
DR. NORTH. It happens all the time in science.
CHAIRMAN BARTON. Yes, and not be substantiated by what you purport to be the facts but have we established-we know that Dr. Wegman has said that Dr. Mann's methodology is incorrect. Do you agree with that? I mean, it doesn't mean Dr. Mann's conclusions are wrong, but we can stipulate now that we have-and if you want to ask your statistician expert from North Carolina that Dr. Mann's methodology cannot be documented and cannot be verified by independent review.
DR. NORTH. Do you mind if he speaks?
CHAIRMAN BARTON. Yes, if he would like to come to the microphone.
MR. BLOOMFIELD. Thank you. Yes, Peter Bloomfield. Our committee reviewed the methodology used by Dr. Mann and his coworkers and we felt that some of the choices they made were inappropriate. We had much the same misgivings about his work that was documented at much greater length by Dr. Wegman.

So what does a top-ranked statistician say about Mann and about McIntyre and McKitrick's criticism? Take it away Dr Wegman:

"Where we have commonality, I believe our report and the [NAS] panel essentially agree. We believe that our discussion together with the discussion from the NRC report should take the `centering' issue off the table. [Mann's] decentred methodology is simply incorrect mathematics .... I am baffled by the claim that the incorrect method doesn't matter because the answer is correct anyway.
Method Wrong + Answer Correct = Bad Science.

The papers of Mann et al. in themselves are written in a confusing manner, making it difficult for the reader to discern the actual methodology and what uncertainty is actually associated with these reconstructions.

It is not clear that Dr. Mann and his associates even realized that their methodology was faulty at the time of writing the [Mann] paper.

We found MBH98 and MBH99 to be somewhat obscure and incomplete and the criticisms of MM03/05a/05b to be valid and compelling.

Overall, our committee believes that Mann's assessments that the decade of the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis.

So where does this leave Dessler's claims that there have been no mistakes made in the last 18 years?

I can only describe them as "plausible" and certainly no higher than that. Probably specious as well.

The IPCC gave the hockey stick conclusion a low probability of being true by categorizing it as "likely."  Given the peer-reviewed literature, there's no reason to think that assessment was in error.  In fact, it's still the view of the scientific community.  Thus, I still contend the IPCC didn't make a mistake there.

Bottom line: Don't confuse the IPCC with the Mann paper.  They are separate entities.

... and Jim Clarke:

Supporters argue that there is no proof that these other factors are 'significant', forgetting that there is also no proof that CO2 is 'significant'.

"'Our conclusion is that this recent period of warming is likely the warmest in the last millennium,' said John M. Wallace, one of the 12 panel members and a professor of atmospheric sciences at the University of Washington."
http://www.boston.com/news/nation/articles/2006/06/23/nat ...

"Where we speak of `less confidence,' we're more into level of sort of 2 to 1 odds, which IPCC, they interpreted `likely' as that level, roughly two to one odds or better."
http://video.nationalacademies.org/ramgen/news/isbn/03091 ...

The substantive "error" in the Mann et al (1999) paper was the specific language about the 1990s and 1998, which is a claim that cannot be made based on the resolution of the proxy data.  The problem with their PCA method was "not material" and "does not appear to unduly influence reconstructions."

He is later quoted to have said "I am baffled by the claim that the incorrect method doesn't matter because the answer is correct anyway. Method Wrong + Answer Correct = Bad Science."

Let's bury this bit of bad science.

Max

CCE:  "The Hockey Stick is in Chapter 6 of WGI, page 467 along with a dozen newer reconstructions."  [You mean 4AR or 2007 presumably]...  Then you agree that the Hockey Stick is in AR4, was not "expunged," and not a single reconstruction therein shows a MWP warmer than today"

Now that's a bit garbled, but what I actually said, IN PART, and what you misrepresent was:

Black Wallaby:  "If you look carefully [in the 2007 report] you can find a pale shadow of the hockey-stick buried under some of the spaghetti all with nice pastel colours hard to distinguish.  If you look carefully you will see that Esper and Moberg who come from a different club from the manna crowd show a distinct MWP, and the borehole data in particular shows a strong LIA"

I don't know if this language of mine is complicated, but if you actually look at figure 6.10b and cross reference my words, you should be able to work-it-out....try!

You also wrote:

CCE: "None of the statements that you say were "ignored" is in the final version of chapter 6"

Yes, that is true, for instance, there is no mention of the embarrassing corrigendum in Nature, where Mann was forced to admit that 35 SERIES of data claimed to be used were in fact not used, or that Wahl and Ammann's related claims were false, or the ludicrous use of Bristle-Cone Pines, or the inability to calibrate the proxy data since ~1960, where there is a sharp down-trend, not up-trend as would be expected. (after some 10 years, it is still called "The Divergence Problem" ....unsolved)   Need I add more?

If this is to be the standard of debate to be used by you, there does not seem much point in continuing.

When Max Manacker returns from his break, he may have the patience to talk to you about some of your other misrepresentations, but right now, I've lost interest.  

Max

Some months ago you wrote in a blog message to me:

"As far as the temperature back 1300 years is concerned, the IPCC says it's likely that today is the warmest over that period.  As we discussed below, likely is a pretty weak confidence interval, meaning something like a 2 out of 3 chance.  The National Academy also reviewed the surface-temperature reconstruction analyses and concluded it was about a 1 out of 2 chance.  
There is significant uncertainty in these surface-temperature reconstructions, and it would not surprise many people if the MWP turned out to be a smidge warmer than today. Importantly, that would not change our conclusion that humans are still the dominant driver of today's climate."

This seems like a reasonable way to put it, Andrew.

I cannot understand why the MWP should even be relevant to today's warming situation, since: (a) there was certainly no major human involvement in driving MWP temperatures and (b) unlike during the MWP, the IPCC consensus is that "humans are still the dominant driver of today's climate" (as you put it above).

Everyone knows there was also an earlier warm period during historical times (Roman Optimum).  Both the MWP and RO have been confirmed by vegetation and (more rarely) by signs of civilization underneath receding glaciers in the Alps as well as by historical reports throughout the civilized world at the time.  

What does all this have to do with today's situation and why is it even mentioned by IPCC?

The whole paleoclimate section in AR4 WG1 could have best been left out, since it only opens the door for critique and controversy and is totally irrelevant to today's situation.

Don't you agree?

Regards,

Max

Wegman has been totally discredited as a reliable and unbiased critic of anything having to do with AGW.

You should know this. The fact that you go on supporting this biased and in correct information shows that you are not interested in gaining knowledge but are only interested in distributing malicious nonsense.

You should be ashamed of such behaviour.

You should know this. The fact that you go on supporting this biased and in correct information shows that you are not interested in gaining knowledge but are only interested in distributing malicious nonsense.

Really? How?

There's not a statistician of any known ability who disagress with Wegman's analysis, so how is Wegman  "reliable and unbiased critic of anything having to do with AGW". Even the NAS Panel as I've already quoted had no criticism of Wegman, either stated or implied.

In your fevered imagination anyone who contradicts the Hockey Stick and its conclusions is discredited because they don't follow a party line.

You should be ashamed of yourself, but I've seen enough biased and disgraceful alarmism to know that you don't have any shame.

Really? It appears as Figure 1b in the Working Group 1 Summary for Policymakers, Figure 5 in the Technical Summary, twice in Chapter 2 (Figures 2-20 and 2-21) of the main report, and Figures 2-3 and 9-1B in the Synthesis Report.

Even Al Gore used the Hockey Stick (which he misleadingly referred to as Dr Thompson's thermometer) in his polically biased and flawed climate schlockfest "An Inconvenint Truth" to "prove" that the Medieval Warm Period was insignificant compared to 20th Century warming.

The view of the scientific community is that the Hockey Stick is dead, that its errors invalidate its claims and that Steve McIntyre is a force to be reckoned with when it comes to statistical analysis. Many of the Hockey Team are too petrified of him to even respond to simple requests for data used in their statistical models.

Oh, and just to make things nice and neat, there is no evidence in any ice core record that carbon dioxide rise drives temperature rise or indeed that it has any effect. Rather, the temperature rise precedes any carbon dioxide rise by around 800 years, and has done for as long as we have ice core records.

So a central assumption of the climate models (which cannot predict any climate phenomenon even 1 year in advance) is not supported by any empirical evidence.

Now back to sleep Andrew, where the Hockey Sticks rule the Earth and the IPCC never makes mistakes!

From a statistical point that was utter nonsense. Thus he is either a very poor statistician (simple linear regression shows that what he signed was not true) or he is one of the lyin' denyin' band of people who have no regard for the effects of their lies on countless millions of people around the Earth.

Such behaviour is despicable.

Guess he checked both the satellite (UAH) and surface (Hadley) records that show a linear trend of 0.06 degrees C over the past decade, with 1998 the warmest year on record in recent history.

Max

We'll start with "global average temperature": a statistical number based on weather station readings (some good, some bad), some sea readings from ships and satellites and a bunch of non-transparent manipulations, adjustments, etc. to get a "globally averaged temperature anomaly number".  We'll start our record around 1850, when our planet was starting to come out of the Little Ice Age.  Guess what?  It's been getting warmer since then (thank goodness, who wants to shovel all that snow!).  Sure, there was some pretty good warming before there was much CO2 (1910-1945), some significant cooling after WWII when CO2 emissions really started to take off, and then warming since about 1975 (which has started to slow down since 1998, the warmest year in recent history).  But we'll figure out some rationalizations for the bumps in the curve that do not match the recorded increase in atmospheric CO2 and ignore the "plateau" over the latest decade.  So we've tied warming to CO2.

Now let's do the same for hurricanes.  Here we should not start in the early 20th century (when there was a lot of hurricane activity) but rather in 1970 (during a very calm period).  We can ignore the historical cycles (approx. every 25 years), which tell a story we do not want to communicate, i.e. strong activity from 1945 to 1969, while temperature was cooling, weak activity from 1970 to 1994, while temperature was rising.  But if we start our statistic in 1970, and compare this to the more active years since 1995, we can show a recent increasing trend (when there really isn't one).  So now we've tied increased hurricane activity to global warming (caused by CO2, of course).

Sea levels will be our next metric.  The record shows this has been going up pretty slowly and steadily (with wide decadal swings) since measurements started way before there was any anthropogenic CO2 to speak of, as the oceans warm up and expand as we are coming out of the LIA.  The first half of the 20th century had a higher rate of increase (with hardly any CO2) than the second half (when most of the CO2 was emitted).  Because of the wide decadal swings, we need to pick the "just right" starting point, in order show a desired trend (where there really isn't one, just like with the hurricanes).  Let's check the numbers and see where we should start our "trend line".  Looks like if we compare 1961-2003 with 1993-2003 that should do the trick.  (If we had used the most recent decade from 1996 to 2005, this would not be so good, since it shows only around one-third of the 1993-2003 rate and this would not send the desired message.)  So we've shown an accelerating rate of sea level rise and tied it to CO2.  

Like I said, figures don't lie...

Max

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.

I haven't read this much tripe since the last time I saw the editorial page of the Wall Street Journal.

No accurate figures don't lie, but manacker and his sock puppet black wallaby do lie constantly.

I'm no scientist but I can plainly see recent anthropogenic CO2 levels pushing the CO2 line higher than anytime in those hundreds of thousands of years.

You pinheads give me one good reason that unprecedented level of CO2 would NOT cause unprecedented levels of heat trapping?  Hello?

Also, can you explain why the predictions of earlier IPCC reports concerning temp rise and ice melting were LOWER than what has actually transpired?  How does that make for an organization who is just bent on scaring us?  They cant even be scary enough to match what's happening!

2. The Hockey Stick was in AR4.  You admit that it was in AR4.  Stop saying it wasn't in AR4.
   
3. If you will look closely, Esper and Moberg are no more prominent than the supposedly "discredited" Hockey Stick, or Mann's 2003 update of it.
   
4. The corrigendum was to correct the descriptions of the data.  It had nothing to do with the calculations that went into the Hockey Stick, nor is it relevent to the findings of the IPCC.
   
5. The NRC panel disagrees with your assessment of the Wahl and Ammann paper.

And for Wegman to sign on to the "no net warming since 1998" statement does not lend credence to his impartiality.  The AGW signal is less than 0.02 degrees per year.   Year to year variability is several times that.  No one can look at the last 10 years and conclude that AGW has stopped because of "no net warming."

Other matters:
The direct effect of CO2 is something like 1.2 degrees for doubled levels.  The rest is primarily the water vapor feedback.  Increase the temperature of the earth, and you increase the moisture content of the atmosphere.  As to cloud feedbacks, we have good information on high level clouds and they can't explain the warming.  We have conflicting information on low level clouds, and best case scenario, they don't explain the warming either.  We have satellite measurements of solar output in the last 30 years with virtually no change other than the 11 year cycle.  The ocean does not create heat, the most it can do (on time scales we're talking about) is change the short term climate (el nino/la nino etc) or push energy around the earth.  It is not going to somehow change the energy balance of the planet.

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!

Now to the question of whether they should have included the hockey stick at all, I think you can go both ways.  On the one hand, you want the report to be as complete as possible.  On the other, you probably don't want to put out uncertain science, particularly when people don't read the caveats.  If it turns out to be wrong, then you look bad --- even if you said originally that you had low confidence in that conclusion.

The effect of aerosols is immediate, whereas CO2 is cumulative.  While CO2 levels were increasing incrementally, anthropogenic sulfur dioxide emissions began increasing exponentially, leveling off in the '70s, and peaking in the late '80s.

ENSO affects the short term climate as energy is transferred between the ocean and atmosphere.  ENSO does not affect the long term energy balance of the world.

If solar was increasing, the daytime temperatures would be warming faster than the nighttime temperatures (the opposite is the case) and the stratosphere would be warming instead of cooling.  Climate sensitivity has been derived from numerous methods, among them the ice cores and other paleo data, and from modern volcanic eruptions, in addition to simple and complex model calculations.  Additionally, we have measured the changes in outgoing longwave radiation from space.

About 1/3rd of the temperature change during deglaciation/glaciation is caused by the change in greenhouse gases, with the another third caused by the albedo changes of ice cover and sea levels and another third caused by vegetation, and atmospheric dust.  The temperature changes of ice ages cannot be explained if you remove the GHG component.  Ice ages themselves are initiated by orbital changes of the earth which redistribute energy to different parts of the earth at different times of the year, facilitating the buildup or destruction of icesheets on (mostly) North America and Europe, and thus increasing the albedo of the Earth.

The AGW signal is less than 0.02 degrees per year, which is dwarfed by natural variation on short time scales.

One party uses models to make predictions about climate. The scientists who designed these models hypothesize that they are correct because they are based on a fairly good, global understanding of how weather systems and climate works. They also publish books describing these models. Scientists are also aware of the complexity of the systems they are trying to model, so they don't put too much stock in them (hence, the word "likely").

The other party defends their position by pointing out possible flaws in the models. People belonging to this party publish articles and books bashing the current scientific understanding of climate change.

Notice the asymmetry in the debate: the onus is on one of the parties to develop a scientific understanding of climate. There is no attempt by one of the parties to propose alternative predictive models, and publish scientific articles demonstrating the viability of these models. Once they start doing this, I will take more time to listen to their arguments.

Peter

I see both:  I sometimes see CO2 coming before warming and sometimes I see warming coming before CO2 rise.  They dance.  You are relating only one side of this because you dont want to see a carbon cap and carbon tax and the energy transition.

Relax.  Nobody is going to send you to a cave to live.   No black helicopters are going to take your guns away.  You can choose any color of plug-in hybrid you want!

It's not quite that simple, Peter.

Yes, "one party uses models to make predictions about climate".  Let's call this party "the IPCC scientists".  This group contains true climate experts, such as Andrew Dessler, plus some technicians that are not-scientists in the true sense, such as computer modelers, etc.

And the other party looks for flaws in the models and predictions.  Let's call this party "the skeptics". This group also contains some climate scientists, like John Christy and Richard Lindzen, but also contains some non-scientists, like some of the blog writers on this site.

There is a third party involved, however.  These are the politicians and bureaucrats who, via a sensationalist media, are using the model predictions to frighten the general public into accepting policy changes that will cost them a lot of money (and make a lot of money for some people).  This party does not shy away from hyperbole, exaggeration and fear mongering to get support for their political agenda.  Let's call this party the "AGW politicians". This group includes Al Gore, (IPCC Chairman) Rajendra K. Pachauri, (UN Secretary General) Ban Ki Moon, (climate scientist turned political alarmist) James E. Hansen, etc.  

Another group of politicians, such as US Senator James Inhofe, are the "anti AGW politicians", and some of these may be supported by groups that stand to lose from the proposed IPCC policy changes.

The model predictions show that the proposed IPCC policy changes (carbon cap and trade schemes or taxes) will do almost nothing to resolve the projected virtual climate problem, if it indeed exists.  Everyone agrees, however, that they will be very costly for the average person living in the industrially developed world, while some groups (hedge funds, carbon traders, etc.) plus government tax coffers will benefit.  Energy trading companies (like the now-defunct Enron) would be among those that stand to make large profits.

And that is why the second party (skeptics) is looking for any flaws, not only in the virtual model projections, but also in the arguments used by the AGW politicians to sell their political agenda.

If it were purely a scientific debate it would be correct to say that it is unfair that "the onus is on one of the parties to develop a scientific understanding of climate" while the other side does not have to live to this same standard.  But it is not purely a scientific debate and developing "a scientific understanding of climate" is not the true ultimate goal of the third party, the AGW politicians (who are driving and funding the IPCC scientists).

And that is why the IPCC scientists must be held to a higher standard of scientific accuracy and objectivity than those who question them.  The onus of proof is, by definition, on the IPCC scientists, rather than on their skeptics.

There are, of course, some scientific reports by skeptical scientists (far fewer than those published by the well-funded IPCC scientists, of course), and these should be held to the same standard as those published by the IPCC scientists.

Max

1) I have no idea what you think I have "no excuse" for not knowing.  MBH99 was in the TAR.  MBH99 is in AR4.  The probability was 66% that recent decades were warmer than the last 1000 years.  That is not screaming by any definition of the word.

RESPONSE: Seven or more `Battleships' and a single `Kyak' can all be described as boats, but they are different.  The former can be scary, the latter innocuous.  The battleships of 2001, were clarioned in every nook and cranny of the various reports, and at podia etc, and had a huge effect of scaring policymakers and media into believing that the current warming was not only unprecedented, but that there was virtually NO VARIATION in the last 1000 years. (Untrue)  The kyak version of 2007 (AR4) is barely perceptible, being hidden "amongst the reeds".

2) The Hockey Stick was in AR4.  You admit that it was in AR4.  Stop saying it wasn't in AR4.

RESPONSE:  There are lots of battleships in 3AR, and only a kyak, obscured by other stuff, both visually and in the text in 4AR.

3) If you will look closely, Esper and Moberg are no more prominent than the supposedly "discredited" Hockey Stick, or Mann's 2003 update of it.

RESPONSE:  IF you look closely amongst all that spaghetti, you will see that Esper and Moberg show a pronounced MWP.  Also the bore-hole data shows a very strong LIA.  This compares with a dead-straight "shaft" on the original hockey-stick.  The original grossly exaggerated up-turn at the end of UNSMOOTHED instrumental data ending at the 1988 spike is absent.  It also has a different smoothing in the proxy data.

4) The corrigendum was to correct the descriptions of the data.  It had nothing to do with the calculations that went into the Hockey Stick, nor is it relevent to the findings of the IPCC.

RESPONSE: The omission of 35 SERIES of data (not 35 data POINTS) that were claimed to be used but were not, and which required the intervention of Nature to compel Mann to own-up is not a minor matter.   Bad data in = bad result out.

5) The NRC panel disagrees with your assessment of the Wahl and Ammann paper.   [Which one BTW?]

RESPONSE:  I have not given my assessment of W & A, but have quoted a SINGLE expert review comment which was vindicated by Nature, and ignored by the IPCC.  The NRC is not the only source of information.

BTW, you don't offer your wisdom on the ludicrous use of Bristle Cone pines or the serious "Divergence Problem" also ignored by the IPCC.... or the other problems I mentioned.

I get the impression that you must get all this nonsense from reading RealClimate website.  This was set-up by the inventors of the hockey-stick, and in the opinion of many rationalists, they are an insult to science.

Oh, and notice Dr, Andrew Dessler's opinions above in a couple of posts concerning the Hocky-stick.  Please read them very carefully, and don't put into them what you WANT him to say.  While you are at it, why don't you read my earlier post more carefully too?  It's a puzzle how you could get it so wrong!

I agree with what you wrote earlier as well as recently:

"You are correct that the hockey stick plot is not a key piece of evidence in attributing today's warming to humans."

I would say that it is a piece of "bad science" that has since been refuted and replaced by better studies that show a somewhat different result.  You might word this differently, but you agree that it "is not a key piece of evidence".

But more importantly, what was its intent?

It may have been just to put the current warming trend into perspective.

Or maybe it was to alarm "policymakers" into thinking that we are facing an unprecedented global warming today, which we have never experienced in historical times, and which could lead to disastrous consequences for humanity as well as for many other species on Earth today.

While the scientists who put the hockey stick together (and the peer reviewers that rubber-stamped it) may have been thinking only of the first reason (giving them the benefit of the doubt), it is quite obvious that the politicians who have used it to further their agendas were thinking of the second reason of spreading fear in order to gain support for their political goals.

And I believe that this is the reason why many skeptics like Jim Clarke keep harping on this issue, and why (in my opinion) the IPCC would be well advised to clearly distance itself from the hockey stick, rather than trying to rationalize its way out of its scientific relevance as it has done in the most recent AR4 WG1 report.

Just my thoughts on this, Andrew.

Regards,

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!

Since you seem to be quite the scientist, try this one:

Yesterday, (Wed.) the daytime maximum was 24C but during the afternoon it fell to 16C, and during the night, the max was 13C.
The day before, the daytime maximum was 35C, and the night-time maximum was 29C.  (Hot)
This weather statement was centred on the ease of sleeping at night, and the night-time minimums were not mentioned in that report.
In a NE suburb close-by to mine, it is usually about 1C cooler, and even 3C cooler after a hot SUNNY day, at night.  (Not if overcast and hot)

The big sudden swings in temperature can result from a change of wind direction from southerly to northerly.  From the north, it comes from the hot dry inland, and from the south from ocean.  This is a CHAOTIC process, almost impossible to forecast more than a few days-out.  It is said somewhat in humour, that a butterfly flapping its wings somewhere, thousands of kilometres away may cause such things.

Please work-out for me what you think the diurnal average max temperature for Melbourne was last Tues. & Wed, and tell me if you think it has any relevance to anything in particular.

Thanking you in anticipation, Black Wallaby

The Carbon Tax Center (CTC) is a New York based non-profit, non-governmental organization formed in 2007 by economist Charles Komanoff and attorney Dan Rosenblum.  This group supports the concept of carbon taxes rather than cap and trade schemes, which are preferred by some other groups, in an attempt to "solve" the perceived global warming problem.

For a link to their thoughts check:
http://www.carbontax.org/issues/carbon-taxes-vs-cap-and-t ...

This group writes:

"Why A Carbon Tax?

The rationale for a carbon tax is simple: the levels of CO2 already in the Earth's atmosphere and being added daily are destabilizing established climate patterns and threatening the ecosystems on which we and other living beings depend. Very large and rapid reductions in the United States' and other nations' carbon emissions are essential to reverse runaway climate change and avert resulting severe weather events, inundation of coastal areas, spread of diseases, failure of agriculture and water supply, infrastructure destruction, forced migrations, political upheavals and international conflict."

Its preference for carbon taxes rather than cap and trade schemes is expressed in:the quotations below:
1.    Carbon taxes will lend predictability to energy prices, whereas cap-and-trade systems will aggravate the price volatility that historically has discouraged investments in less carbon-intensive electricity generation, carbon-reducing energy efficiency and carbon-replacing renewable energy
2.    Carbon taxes can be implemented much sooner than complex cap-and-trade systems. Because of the urgency of the climate crisis, we do not have the luxury of waiting while the myriad details of a cap-and-trade system are resolved through lengthy negotiations
3.    Carbon taxes are transparent and easily understandable, making them more likely to elicit the necessary public support than an opaque and difficult to understand cap-and-trade system
4.    Carbon taxes can be implemented with far less opportunity for manipulation by special interests, while a cap-and-trade system's complexity opens it to exploitation by special interests and perverse incentives that can undermine public confidence and undercut its effectiveness
5.    Carbon taxes address emissions of carbon from every secctor, whereas cap-and-trade systems discussed to date have only targeted the electricity industry, which accounts for less than 40% of emission
6.    Carbon tax revenues can be returned to the public through progressive tax-shifting while the costs of cap-and-trade systems are likely to become a hidden tax as dollars flow to market participants, lawyers and consultants

This rationale for a major tax increase on humanity is based on its own rather exaggerated interpretation of IPCC reports, so it is extremely important that these reports be as accurate and objective as possible and that any exaggerations be questioned critically.

According to the Carbon Tax Center, a tax that grows at an annual rate "equivalent to 5-10% of the `baseline' cost of fossil fuels offers a viable combination of meaningful incentive and opportunity for adaptation". CTC concludes that the proposed $37 per ton of carbon "starter tax", which it equates to around 10 cents a gallon of gasoline, "fits the lower end of that range".

A tax of 10 cents per gallon of gasoline sounds fairly innocuous, so what's the concern?  Even if the "starter rate" of $37 per ton quickly grows to a more significant $100 per ton, as the CTC expects, this still only represents around 30 cents on a gallon of gasoline.

To understand the true cost of a $100 per ton carbon tax, however, one has to look at the whole picture, not just the US price of gasoline.

Based on the total CO2 emissions of the USA, a $100 per ton carbon tax would cost US households approximately 158 billion dollars per year in total.  The average total cost per household would be around $1700 per year.  Roughly half of this ($800 per household per year) would be the direct cost of the carbon tax on direct energy costs (transportation and other energy) and the rest ($900 per year) would be the indirect cost of the carbon tax on the energy component of all products purchased (assuming these costs would all be ultimately passed on to the consumer).

Interestingly, the easily visible direct cost increase for gasoline mentioned by CTC (around 30 cents per gallon) would be the smallest component, since gasoline is already heavily taxed and, thus, quite expensive per unit of carbon emitted. On the other hand, the more hidden direct cost of non-transportation energy (electrical power, natural gas or heating oil) would be increased by over 30%.

On a per capita basis, those living in the USA would pay the highest rate (at $522 per year), while those living in other major emitting nations such as Russia ($327), Japan ($301), the EU ($235), China ($128) and India ($31) would pay a lower rate. On a world total, the tax would amount to $740 billion annually, so that, on average, every human being, man, woman and child, would pay around $110 per year.

In the above calculation, it is assumed that each country would pay carbon tax based on the emissions caused by that country.  The indirect carbon tax component of goods produced in China and consumed in the USA, for example, would presumably be passed on to the final consumer, so that the net impact on US households would be somewhat higher and that on Chinese households would be somewhat less.  So the tax would end up being sort of like a "sales tax", where the end consumer pays based on his/her consumption of goods that have a "carbon footprint".

Other groups propose carbon caps with an auction on carbon allowances and annually lowering carbon permits rather than taxes, but the net effect is the same.
http://www.newrules.org/de/carboncaps-dividends.pdf  

These schemes may be less transparent than a direct carbon tax (as CTC surmises), and there may be more "middle men" (like Al Gore) earning a profit from these schemes (rather than the government tax coffers), but the same person ends up "footing the bill": the consumer.  

The argument by groups such as the "New Rules Project" that introducing a "universal dividend" can make carbon cap and trade schemes "ethical, equitable and politically effective" is flawed, because it ignores the fact that the whole scheme must be paid by someone, and that someone will end up being the consumer.  Shifting the load away from the less affluent to the more affluent consumer is just a socialistic exercise that does not change anything: in the end effect, it is still the consumer who pays.

Since the whole urgency of "necessity to act now" is based on dubious science to start off with, it is best that we hold off implementing either of these schemes, that (as most people agree) will not resolve the problem in any case (if it even exists), until we can be really sure that the science is sound.

Do we really want to do all this?  I don't think so.

Just my opinion, but I welcome comments from those who might disagree.

Max

~~~~~~~~~~From Ch. 6, Pg 466 WG1, AR4~~~~~~~~~~~~~~~~~~~~
The `hockey stick' reconstruction of Mann et al. (1999) has been the subject of several critical studies. Soon and Baliunas (2003) challenged the conclusion that the 20th century was the warmest at a hemispheric average scale. They surveyed regionally diverse proxy climate data, noting evidence for relatively warm (or cold), or alternatively dry (or wet) conditions occurring at any time within pre-defined periods assumed to bracket the so-called `Medieval Warm Period' (and `Little Ice Age'). Their qualitative approach precluded any quantitative summary of the evidence at precise times, limiting the value of their review as a basis for comparison of the relative magnitude of mean hemispheric 20th-century warmth (Mann and Jones, 2003; Osborn and Briffa, 2006). Box 6.4 provides more information on the `Medieval Warm Period'.
McIntyre and McKitrick (2003) reported that they were unable to replicate the results of Mann et al. (1998). Wahl and Ammann (2007) showed that this was a consequence of differences in the way McIntyre and McKitrick (2003) had implemented the method of Mann et al. (1998) and that the original reconstruction could be closely duplicated using the original proxy data. McIntyre and McKitrick (2005a,b) raised further concerns about the details of the Mann et al. (1998) method, principally relating to the independent verification of the reconstruction against 19th-century instrumental temperature data and to the extraction of the dominant modes of variability present in a network of western North American tree ring chronologies, using Principal Components Analysis. The latter may have some theoretical foundation, but Wahl and Amman (2006) also show that the impact on the amplitude of the final reconstruction is very small (~0.05°C; for further discussion of these issues see also Huybers, 2005; McIntyre and McKitrick, 2005c,d; von Storch and Zorita, 2005).

Since the TAR, a number of additional proxy data syntheses based on annually or near-annually resolved data, variously representing mean.....etc etc

I admit I was being a bit simplistic for effect.

It is unfortunate that we distinguish between "scientists" and "skeptics"; good science implies skepticism.

It is also unfortunate that skeptics are viewed as being "anti-AGW" (to use your terminology). I'm sure many skeptics (perhaps a majority?) lean toward the conclusions of the IPCC, but rally against outlandish claims, or hyperbole.

I suppose my greatest fear is that in our current political and media environment, hyperbole is the only effective way to get the message out to the public that climate change is a problem we need to (and can!) address, especially when it has to compete with: War on Terror, How Illegal Immigrants are Stealing Your Jobs, etc.

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!)