Global cooling

[Russell Kanning]

I like his reference to "DHMO".

[Ear]

(I want to preface this post by saying that, in general, I consider the Democrats the lesser of two evils when compared with the Republicans, and that I do wish Al Gore had been installed in the White House instead of George Bush.  Call me crazy, but I'd rather pay higher taxes for social programs I don't want than have my tax dollars used to bomb civilians in some other country for no good reason other than naked greed and corporate welfare.  I'd rather have to fight the Nanny State than have to fight the Fascists, in other words.)

Recently, I've started thinking hard about where I stand on the global warming issue... I'm a pretty skeptical person with a good understanding of how the scientific method works and how scientists go about doing their thing, and the controversy that one sees in the popular press regarding global warming seems to suggest to me that nobody really knows one way or the other if it's real or not.

A few days ago, I downloaded and watched AN INCONVENIENT TRUTH, and the film left me with some huge questions.  The data that Al Gore presented seemed fairly compelling (if it's true), but the segments of his presentation that were not solely concerned with showing us hard data struck me as being self-aggrandizing and phony.  In the end, the film just confused me, because I remembered that after the scandalous election results in 2000, Gore declined to file a lawsuit and fight for the Presidency on the grounds that to do so would create a "Constitutional crisis".  This is significant because, in AN INCONVENIENT TRUTH, Gore claims that he has known about the global warming problem since college.  If that's true, then in 2000 Gore for some reason decided that a "Constitutional crisis" was a worse thing than sitting on the sidelines watching Earth's sea levels rise by twenty feet!

I thought about what conclusions I might draw from Gore's actions (or rather, disaction) in 2000 when contrasted with his statements about global warming and his assertion that he has known about the problem since well before the year 2000.  It seemed to me that the possibilities are as follows:

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  1.  Gore doesn't believe the data he presents in AN INCONVENIENT TRUTH, and is using phony data to scare people, with the objective of drawing attention to himself as the savior of humanity.

  2.  Gore believes the data, but also believes that a "Constitutional crisis" is somehow worse than having an estimated 500,000,000 people become either corpses or refugees as their homes are flooded with seawater (Manhattan and other cities in the U.S. included).

  3.  Gore believes the data, but is lying when he says he has known about the problem since college.

  4.  Gore believes some of the data, but does not believe that sea levels will rise by twenty feet anytime soon.
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Of these four possibilities, the second seems unlikely enough that it can be discarded.  That leaves us with the other three, all of which explain why Gore didn't fight tooth and nail to get into the White House in 2000, where he could have wielded the kind of power necessary to make enough of a difference to save that estimated half billion people.

Although I do certainly favor the Democrats over the Republicans, I don't have any illusions about politicians and their nature, no matter what political party they belong to.  Successful politicians are skilled liars who exhibit little to no conscience about telling lies, particularly when they are puffing themselves up to look good in the eyes of the voters.  What they tell lies about is what makes them good guys or bad guys, not if they lie or not... of course they lie, they're politicians, and politicians lie as sure as rattlesnakes bite.

Which lie did Gore tell?  Is global warming a hoax?  If not, is it merely something that Gore became aware of and concerned about recently, and not in college as he claims, or did he exaggerate the predicted effects of global warming?

It seems more likely that Gore does, in fact, believe the data, and that he either lied about having known about it for so long or lied about the probable effects.  He does, after all, have a vested interest in making himself look good.  There might also be an element of sour grapes over the 2000 election (which to be fair was an unfair victory for Bush).  Sort of a "don't you wish you people had me for President now?" sort of sentiment.  Of those two possibilities, I think it is more likely that he lied about having known about the problem since college.  I say this for several reasons, one of them being that it's a simpler lie, and professional liars always keep these things as simple as possible.  Also, presenting data that says we're going to see massive consequences within fifty years is pretty foolish if you know the data is bogus, because it will leave you with your pants around your ankles in all the history books written more than fifty years later.  Therefore, by logic alone, I tend to believe that Al Gore does believe the data he presented in AN INCONVENIENT TRUTH, and does believe that the consequences of ignoring the data will be catastrophic.

Since using logic alone can lead to fallacies, I figured I'd better do some more research.  In the film, Gore claimed that his team examined articles written by scientists and published in peer-reviewed scientific journals, and compared them with articles merely citing the work of scientists, and published in the popular media (newspapers, books, magazines) without peer review.  Gore's conclusion was that although there is a huge controversy in the popular media, with about fifty percent of the articles on global warming saying it's a real phenomenon and the other fifty percent claiming to debunk it, there is no such controversy in the peer-reviewed scientific publications.  He claimed that there was not even one single article in a peer-reviewed scientific publication that argued against the validity of global warming.  If it's true, then that's pretty compelling evidence that the global warming debunkers are propagandists.

I got in touch with some friends who are actual scientists (two physicists, an expert in aerodynamics, and a research chemist), and had some long conversations with them in which I asked them what they think of all this.  Granted, none of them are climatologists, but they are all real working scientists and are very familiar with peer review within the scientific community.  All of them are political moderates, and neither particularly Liberal nor particularly Conservative in their outlook.  Two of them have a strong interest in the current thinking regarding global warming, and regularly read peer-reviewed scientific journals outside their own disciplines that publish articles on the matter.  I have known all four of them for many years, and trust all of them not to lie to me for political reasons.

They all said the same thing:  Gore is correct, there is zero controversy in the scientific community regarding whether or not global warming is a real phenomenon.  None.  All the experts in the relevant fields agree that global warming is a real phenomenon, and is tied to increased levels of carbon in the atmosphere.

If I was biased, or some kind of alarmist, I'd end there... but I'm not, and that isn't the end at all.  I have established to my own satisfaction (if not yours) that global warming is real, and that it is linked to increased levels of carbon.  The questions I have now are these:

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  1.  Global warming is linked to increased levels of carbon, but is it definitively linked to increased carbon emissions from humanity's activities, or are there other reasonable explanations for the increased carbon levels being seriously debated by real scientists in peer-reviewed journals?

  2.  Given that Gore's data regarding the increasing pace of carbon levels and global warming is valid and uncontested, is he also correct that this will lead to sea levels rising by some twenty feet within the next fifty years?
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I welcome any comments regarding this, but having satisfied myself that the controversy in the public media is heavily propagandized, I will not lend a single iota of credibility to citations of sources that are not strictly peer-reviewed scientific journals.

[error]

Listen to Thursday night's Free Talk Live. Ian had an article on which pretty much debunked the whole climate change bull from one end to the other.

Among the higlights: Global warming is linked to carbon dioxide, but not in the way they want you to believe. And the UN is hiding a lot of data which show global warming alarmism to be pretty much bogus.

And your scientist friends have been duped: the so-called "peer reviewed" articles, in a lot of cases, were "reviewed" by people with conflicts of interest and/or agendas to push, and much of it has already been discredited.

As for sea levels rising, get a glass. Fill it with ice. Then fill it with water. Wait for the ice to melt and see how much water spills onto the table.

[Ear]

Listen to Thursday night's Free Talk Live. Ian had an article on which pretty much debunked the whole climate change bull from one end to the other.

There are lots of articles that "debunk" global warming... but none that I can find in peer-reviewed scientific journals.  I know for a fact that popular media is rife with propaganda, so why should I pay attention to the article Ian cited?

Among the higlights: Global warming is linked to carbon dioxide, but not in the way they want you to believe. And the UN is hiding a lot of data which show global warming alarmism to be pretty much bogus.

If the U.N. is hiding data, how is it that you know what the data indicates?

And your scientist friends have been duped: the so-called "peer reviewed" articles, in a lot of cases, were "reviewed" by people with conflicts of interest and/or agendas to push, and much of it has already been discredited.

I'm sorry, I don't mean to be insulting, but this statement simply reveals that you don't have a clue as to how peer review works.  The vast majority of people who read these articles ARE the peers doing the reviewing; they are scientists, with expertise in related fields that gives them the knowledge and tools with which to evaluate the data presented in the articles.  The only way to dupe them would be to present them with consistently false data that is also internally consistent, and in this particular case that would require a conspiracy with many hundreds or thousands of people participating.  Belief in such conspiracies requires nothing short of delusional paranoia.

As for sea levels rising, get a glass. Fill it with ice. Then fill it with water. Wait for the ice to melt and see how much water spills onto the table.

That's certainly true for ice that is submerged in the water before it melts, but Greenland and the Antarctic ice sheets hold a great deal of ice that remains well above sea level as long as it remains frozen.  I just this evening read several articles in reputable, peer-reviewed scientific journals indicating that we could see a rise in sea level between four and six meters (13.12 to 19.7 feet) within the next century, if the current warming trend continues as expected.  Incidentally, about half of the total anticipated rise in sea level is due to thermal expansion of water, not melting ice.

You're obviously not a climatologist... why are you so convinced that you're correct?  The only evidence that you've given for your belief refers to articles published in the popular media, which any fool knows is heavily laden with propaganda of one sort or another.

[error]

I don't need to be a climatologist to know when someone's trying to feed me bullshit.

As for the popular media, they're a large part of the problem.

For a very quick catch-up, please read geologist Dr. David Deming's testimony before Congress this week: " I reviewed how borehole temperature data recorded a warming of about one degree Celsius in North America over the last 100 to 150 years. The week the article appeared, I was contacted by a reporter for National Public Radio. He offered to interview me, but only if I would state that the warming was due to human activity. When I refused to do so, he hung up on me." http://epw.senate.gov/hearing_statements.cfm?id=266543

And environmental scientist Dr. R.M. Carter: "The science reality is that climate is a complex, dynamic, natural system that no one wholly comprehends, though many scientists understand different small parts. Science provides no unambiguous empirical data that dangerous or even measurable human-caused global warming is occurring (e.g. Khilyuk & Chilingar, 2006)." http://epw.senate.gov/109th/Carter_Testimony.pdf

I could dig up much more, but these just happened to be easily accessible, having crossed my desk this week.

So, did you come here for a frank discussion of the issues, or to troll?

[error]

Ah, here it is. Complete with references:

http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/05/nosplit/nwarm05.xml

[Ear]

"...I was contacted by a reporter for National Public Radio.

National Public Radio is the popular media, not a peer-reviewed scientific journal.  You've just proved my point that the popular media is rife with propaganda.  Why would you believe it either way?  Are you saying that just because you can point to popular media propaganda that is counter to what you want to believe, there must not be any propaganda promoting what you do believe?

He offered to interview me, but only if I would state that the warming was due to human activity. When I refused to do so, he hung up on me."

Did you read my original post?  I NEVER said that global warming is definitely caused by human activity... in fact I posed the question of whether or not that assertion is contested within the scientific community.

And environmental scientist Dr. R.M. Carter: "The science reality is that climate is a complex, dynamic, natural system that no one wholly comprehends, though many scientists understand different small parts. Science provides no unambiguous empirical data that dangerous or even measurable human-caused global warming is occurring (e.g. Khilyuk & Chilingar, 2006)."

Once again you quote from popular media instead of a peer-reviewed scientific journal, AND you once again raise the straw-man argument regarding HUMAN-CAUSED global warming.

So, did you come here for a frank discussion of the issues, or to troll?

I might ask you the same question, since you've twice raised a straw-man argument against me.

Here, let me just quote myself real quick:

I have established to my own satisfaction (if not yours) that global warming is real, and that it is linked to increased levels of carbon.  The questions I have now are these:

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  1.  Global warming is linked to increased levels of carbon, but is it definitively linked to increased carbon emissions from humanity's activities, or are there other reasonable explanations for the increased carbon levels being seriously debated by real scientists in peer-reviewed journals?

  2.  Given that Gore's data regarding the increasing pace of carbon levels and global warming is valid and uncontested, is he also correct that this will lead to sea levels rising by some twenty feet within the next fifty years?
==============================================================================

The reading I've done since posting that has led me to tentatively conclude that I have an answer for question 2.: Gore's data is indeed valid and uncontested in peer-reviewed scientific journals, but his estimate of sea levels rising twenty feet is a worst-case scenario, and his estimate of this occurring within fifty years is modestly alarmist, since the current accepted worst-case scenario is just under twenty feet of rise in sea level within a century, not within fifty years.

[error]

Actually, I quoted the scientists, not the media.

To make clear the answer to your two questions, then:

I've seen NO consensus from actual scientists on how much of global warming is caused by human activity. My understanding is that it's still hotly debated.

Nobody's disputing that global warming has been taking place. That much has been confirmed over and over and over and over and over again in the literature. But I've also seen NO consensus on how much sea levels might rise. Indeed, they might rise 20 feet, or might not rise perceptibly at all. (But 20 feet would sink a lot of socialist stronghold cities!)

[Ear]

Ah, here it is. Complete with references:

http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/05/nosplit/nwarm05.xml

Wow, this is a perfect example of the kind of propaganda I'm talking about.  The .pdf that is linked in that article is a report from Christopher Monckton, who is often mentioned in actual scientific journals as a man who publishes pseudo-science in the popular media that looks like good science (but isn't) and deliberately misleads the public.  Here is a debunking of the methods Monckton uses in the report your article refers to:

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Sometimes we discuss important scientific uncertainties, and sometimes we try and clarify some subtle point or context, but at other times, we have a little fun in pointing out some of the absurdities that occasionally pass for serious 'science' on the web and in the media. These pieces look scientific to the layperson (they have equations! references to 19th Century physicists!), but like cuckoo eggs in a nest, they are only designed to look real enough to fool onlookers and crowd out the real science. A cursory glance from anyone knowledgeable is usually enough to see that concepts are being mangled, logic is being thrown to the winds, and completetly unjustified conclusions are being drawn - but the tricks being used are sometimes a little subtle.

Two pieces that have recently drawn some attention fit this mould exactly. One by Christopher Monckton (a viscount, no less, with obviously too much time on his hands) which comes complete with supplementary 'calculations' using his own 'M' model of climate, and one on JunkScience.com ('What Watt is What'). Junk Science is a front end for Steve Milloy, long time tobacco, drug and oil industry lobbyist, and who has been a reliable source for these 'cuckoo science' pieces for years. Curiously enough, both pieces use some of the same sleight-of-hand to fool the unwary (coincidence?).

The two pieces both spend a lot of time discussing ty but since they don't clearly say so upfront, it might not at first be obvious. (This is possibly because if you google the words 'climate sensitivity' you get very sensible discussions of the concept from Wikipedia, ourselves and the National Academies). We have often made the case here that equilibrium climate sensitivity is most likely to be around 0.75 +/- 0.25 C/(W/m2) (corresponding to about a 3?C rise for a doubling of CO2).

Both these pieces instead purport to show using 'common sense' arguments that climate sensitivity must be small (more like 0.2 W/m2, or less than 1?C for 2xCO2). We have demonstrated many times in the past that this can't be correct, but it's worth seeing how they arithimetically manage to get these answers. To save you having to wade through it all, I'll give you the answer now: the clue is in the units of climate sensitivity - ?C/(W/m2). Any temperature change (in ?C) divided by any energy flux (in W/m2) will have the same unit and thus can be 'compared'. But unless you understand how radiative forcing is defined (it's actually quite specific), and why it's a useful diagnostic, these similar seeming values could be confusing. Which is presumably the point.

Readers need to be aware of at least two basic things. First off, an idealised 'black body' (which gives of radiation in a very uniform and predictable way as a function of temperature - encapsulated in the Stefan-Boltzmann equation) has a basic sensitivity (at Earth's radiating temperature) of about 0.27 ?C/(W/m2). That is, a change in radiative forcing of about 4 W/m2 would give around 1?C warming. The second thing to know is that the Earth is not a black body! On the real planet, there are multitudes of feedbacks that affect other greenhouse components (ice albedo, water vapour, clouds etc.) and so the true issue for climate sensitivity is what these feedbacks amount to.

So here's the first trick. Ignore all the feedbacks - then you will obviously get to a number that is close to the 'black body' calculation. Any calculation that lumps together water vapour and CO2 is effectively doing this (and if anyone is any doubt about whether water vapour is forcing or a feedback, I'd refer them to this older article).

As we explain in our glossary item, climatologists use the concept of radiative forcing and climate sensitivity because it provides a very robust predictive tool for knowing what model results will be, given a change of forcing. The climate sensitivity is an output of complex models (it is not decided ahead of time) and it doesn't help as much with the details of the response (i.e. regional patterns or changes in variance), but it's still quite useful for many broad brush responses. Empirically, we know that for a particular model, once you know its climate sensitivity you can easily predict how much it will warm or cool if you change one of the forcings (like CO2 or solar). We also know that the best definition of the forcing is the change in flux at the tropopause, and that the most predictable diagnostic is the global mean surface temperature anomaly. Thus it is natural to look at the real world and see whether there is evidence that it behaves in the same way (and it appears to, since model hindcasts of past changes match observations very well).

So for our next trick, try dividing energy fluxes at the surface by temperature changes at the surface. As is obvious, this isn't the same as the definition of climate sensitivity - it is in fact the same as the black body (no feedback case) discussed above - and so, again it's no surprise when the numbers come up as similar to the black body case.

But we are still not done! The next thing to conveniently forget is that climate sensitivity is an equilibrium concept. It tells you the temperature that you get to eventually. In a transient situation (such as we have at present), there is a lag related to the slow warm up of the oceans, which implies that the temperature takes a number of decades to catch up with the forcings. This lag is associated with the planetary energy imbalance and the rise in ocean heat content. If you don't take that into account it will always make the observed 'sensitivity' smaller than it should be. Therefore if you take the observed warming (0.6?C) and divide by the estimated total forcings (~1.6 +/- 1W/m2) you get a number that is roughly half the one expected. You can even go one better - if you ignore the fact that there are negative forcings in the system as well (chiefly aerosols and land use changes), the forcing from all the warming effects is larger still (~2.6 W/m2), and so the implied sensitivity even smaller! Of course, you could take the imbalance (~0.33 +/- 0.23 W/m2 in a recent paper) into account and use the total net forcing, but that would give you something that includes 3?C for 2xCO2 in the error bars, and that wouldn't be useful, would it?

And finally, you can completely contradict all your prior working by implying that all the warming is due to solar forcing. Why is this contradictory? Because all of the above tricks work for solar forcings as well as greenhouse gas forcings. Either there are important feedbacks or there aren't. You can't have them for solar and not for greenhouse gases. Our best estimates of solar are that it is about 10 to 15% the magnitude of the greenhouse gas forcing over the 20th Century. Even if that is wrong by a factor of 2 (which is conceivable), it's still less than half of the GHG changes. And of course, when you look at the last 50 years, there are no trends in solar forcing at all. Maybe it's best not to mention that.

There you have it. The cuckoo has come in and displaced the whole field of climate science. Impressive, yes? No, not really.
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[Ear]

Actually, I quoted the scientists, not the media.

What you quoted was the popular media quoting a purported scientist.

This is a far cry from quoting an article written by a scientist in a peer-reviewed scientific journal.

[error]

Now I know I've been at this too long, because I actually understood that.

But it only addresses one of numerous issues that Monckton raised. (And remember that I heard this on a RADIO SHOW, haven't had a chance to get into it in depth.)

Some of the other stuff, such as the hockey stick graph, I've looked at previously for unrelated reasons. I haven't yet learned whether that was simply a mistake or deliberate deception. But it does show the propaganda is flying on all sides of this issue.

This is hard enough for people who know what the scientific method is. How are we supposed to expect Joe Public to figure it out?

[error]

Actually, I quoted the scientists, not the media.

What you quoted was the popular media quoting a purported scientist.

This is a far cry from quoting an article written by a scientist in a peer-reviewed scientific journal.

Why do you keep saying I quoted the media when it's perfectly clear that I quoted the scientists themselves from their own Congressional testimony (which contain the references to the peer-reviewed scientific journals)?

[Ear]

Why do you keep saying I quoted the media when it's perfectly clear that I quoted the scientists themselves from their own Congressional testimony (which contain the references to the peer-reviewed scientific journals)?

My mistake, I thought you were referring to a different quote... but although the Congressional record is not the popular media, it is also not a peer-reviewed scientific journal... and I can't think of a more politically-motivated place for propaganda to be introduced than a Congressional hearing, can you?  Who chose those particular gentlemen to testify, and why?

[Ear]

But it only addresses one of numerous issues that Monckton raised. (And remember that I heard this on a RADIO SHOW, haven't had a chance to get into it in depth.)

It really doesn't much matter what other issues Monckton may have raised, since THAT issue shows that he's clearly a snakeoil salesman.  What, do you expect him to go to all that trouble to provide misleading "evidence" and then turn around and stop lying the next minute?  Monckton doesn't publish his pap in peer-reviewed journals because they are peer-reviewed and he would be making a fool of himself.

Some of the other stuff, such as the hockey stick graph, I've looked at previously for unrelated reasons. I haven't yet learned whether that was simply a mistake or deliberate deception. But it does show the propaganda is flying on all sides of this issue.

It only shows that propaganda is flying on all sides of the issue if you believe the propaganda regarding the hockey stick graph, actually.

I happen to have some very good information on that for you, with citations from peer-reviewed scientific journals.  Get a cup of coffee, settle in, and prepare to have another scale peeled forcibly from your eyes:

Myth vs. Fact Regarding the "Hockey Stick"

Numerous myths regarding the so-called "hockey stick" reconstruction of past temperatures, can be found on various non-peer reviewed websites, internet newsgroups and other non-scientific venues. The most widespread of these myths are debunked below:

MYTH #0: Evidence for modern human influence on climate rests entirely upon the "Hockey Stick" Reconstruction of Northern Hemisphere mean temperatures indicating anomalous late 20th century warmth.

This peculiar suggestion is sometimes found in op-ed pieces and other dubious propaganda, despite its transparent absurdity. Paleoclimate evidence is simply one in a number of independent lines of evidence indicating the strong likelihood that human influences on climate play a dominant role in the observed 20th century warming of the earth's surface. Perhaps the strongest piece of evidence in support of this conclusion is the evidence from so-called "Detection and Attribution Studies". Such studies demonstrate that the pattern of 20th century climate change closely matches that predicted by state-of-the-art models of the climate system in response to 20th century anthropogenic forcing (due to the combined influence of anthropogenic greenhouse gas concentrations and industrial aerosol increases).

MYTH #1: The "Hockey Stick" Reconstruction is based solely on two publications by climate scientist Michael Mann and colleagues (Mann et al, 1998;1999).

This is patently false. Nearly a dozen model-based and proxy-based reconstructions of Northern Hemisphere mean temperature by different groups all suggest that late 20th century warmth is anomalous in a long-term (multi-century to millennial) context.

Some proxy-based reconstructions suggest greater variability than others. This greater variability may be attributable to different emphases in seasonal and spatial emphasis (see Jones and Mann, 2004; Rutherford et al, 2004; Cook et al, 2004). However, even for those reconstructions which suggest a colder "Little Ice Age" and greater variability in general in past centuries, such as that of Esper et al (2002), late 20th century hemispheric warmth is still found to be anomalous in the context of the reconstruction (see Cook et al, 2004).

MYTH #2: Regional proxy evidence of warm or anomalous (wet or dry) conditions in past centuries contradicts the conclusion that late 20th century hemispheric mean warmth is anomalous in a long-term (multi-century to millennial) context.

Such claims reflect a lack of awareness of the distinction between regional and large-scale climate change. Similar such claims were recently made in two articles by astronomer Willie Soon and co-authors (Soon and Baliunas, 2003; Soon et al, 2003). These claims were subsequently rebutted by a group of more than a dozen leading climate scientists in an article in the journal "Eos" of the American Geophysical Union (Mann et al, ?Eos?, 2003). The rebuttal raised, among other points, the following two key points:

(1) In drawing conclusions regarding past regional temperature changes from proxy records, it is essential to assess proxy data for actual sensitivity to past temperature variability. In some cases (Soon and Baliunas, 2003, Soon et al, 2003) a global 'warm anomaly' has been defined for any period during which various regions appear to indicate climate anomalies that can be classified as being either 'warm', 'wet', or 'dry' relative to '20th century' conditions. Such a criterion could be used to define any period of climate as 'warm' or 'cold', and thus cannot meaningfully characterize past large-scale surface temperature changes.

(2) It is essential to distinguish (e.g. by compositing or otherwise assimilating different proxy information in a consistent manner?e.g., Jones et al., 1998; Mann et al., 1998, 1999; Briffa et al., 2001) between regional temperature changes and changes in global or hemispheric mean temperature. Specific periods of cold and warmth differ from region to region over the globe (see Jones and Mann, 2004), as changes in atmospheric circulation over time exhibit a wave-like character, ensuring that certain regions tend to warm (due, for example, to a southerly flow in the Northern Hemisphere winter mid-latitudes) when other regions cool (due to the corresponding northerly flow that must occur elsewhere). Truly representative estimates of global or hemispheric average temperature must therefore average temperature changes over a sufficiently large number of distinct regions to average out such offsetting regional changes. The specification of a warm period, therefore requires that warm anomalies in different regions should be truly synchronous and not merely required to occur within a very broad interval in time, such as AD 800-1300 (as in Soon et al, 2003; Soon and Baliunas, 2003).

MYTH #3: The "Hockey Stick" studies claim that the 20th century on the whole is the warmest period of the past 1000 years.

This is a mis-characterization of the actual scientific conclusions. Numerous studies suggest that hemispheric mean warmth for the late 20th century (that is, the past few decades) appears to exceed the warmth of any comparable length period over the past thousand years or longer, taking into account the uncertainties in the estimates (see Figure 1 in "Temperature Variations in Past Centuries and The So-Called 'Hockey Stick'"). On the other hand, in the context of the long-term reconstructions, the early 20th century appears to have been a relatively cold period while the mid 20th century was comparable in warmth, by most estimates, to peak Medieval warmth (i.e., the so-called "Medieval Warm Period"). It is not the average 20th century warmth, but the magnitude of warming during the 20th century, and the level of warmth observed during the past few decades, which appear to be anomalous in a long-term context. Studies such as those of Soon and associates (Soon and Baliunas, 2003; Soon et al, 2003) that consider only ?20th century? conditions, or interpret past temperature changes using evidence incapable of resolving trends in recent decades , cannot meaningfully address the question of whether late 20th century warmth is anomalous in a long-term and large-scale context.

MYTH #4: Errors in the "Hockey Stick" undermine the conclusion that late 20th century hemispheric warmth is anomalous.

This statement embraces at least two distinct falsehoods. The first falsehood holds that the "Hockey Stick" is the result of one analysis or the analysis of one group of researchers (i.e., that of Mann et al, 1998 and Mann et al, 1999). However, as discussed in the response to Myth #1 above, the basic conclusions of Mann et al (1998,1999) are affirmed in multiple independent studies. Thus, even if there were errors in the Mann et al (1998) reconstruction, numerous other studies independently support the conclusion of anomalous late 20th century hemispheric-scale warmth.

The second falsehood holds that there are errors in the Mann et al (1998, 1999) analyses, and that these putative errors compromise the "hockey stick" shape of hemispheric surface temperature reconstructions. Such claims seem to be based in part on the misunderstanding or misrepresentation by some individuals of a corrigendum that was published by Mann and colleagues in Nature. This corrigendum simply corrected the descriptions of supplementary information that accompanied the Mann et al article detailing precisely what data were used. As clearly stated in the corrigendum, these corrections have no influence at all on the actual analysis or any of the results shown in Mann et al (1998). Claims that the corrigendum reflects any errors at all in the Mann et al (1998) reconstruction are entirely false.

False claims of the existence of errors in the Mann et al (1998) reconstruction can also be traced to spurious allegations made by two individuals, McIntyre and McKitrick (McIntyre works in the mining industry, while McKitrick is an economist). The false claims were first made in an article (McIntyre and McKitrick, 2003) published in a non-scientific (social science) journal "Energy and Environment" and later, in a separate "Communications Arising" comment that was rejected by Nature based on negative appraisals by reviewers and editor [as a side note, we find it peculiar that the authors have argued elsewhere that their submission was rejected due to 'lack of space'. Nature makes their policy on such submissions quite clear: "The Brief Communications editor will decide how to proceed on the basis of whether the central conclusion of the earlier paper is brought into question; of the length of time since the original publication; and of whether a comment or exchange of views is likely to seem of interest to nonspecialist readers. Because Nature receives so many comments, those that do not meet these criteria are referred to the specialist literature." Since Nature chose to send the comment out for review in the first place, the "time since the original publication" was clearly not deemed a problematic factor. One is logically left to conclude that the grounds for rejection were the deficiencies in the authors' arguments explicitly noted by the reviewers]. The rejected criticism has nonetheless been posted on the internet by the authors, and promoted in certain other non-peer-reviewed venues (see this nice discussion by science journalist David Appell of a scurrilous parroting of their claims by Richard Muller in an on-line opinion piece).

The claims of McIntyre and McKitrick, which hold that the "Hockey-Stick" shape of the MBH98 reconstruction is an artifact of the use of series with infilled data and the convention by which certain networks of proxy data were represented in a Principal Components Analysis ("PCA"), are readily seen to be false , as detailed in a response by Mann and colleagues to their rejected Nature criticism demonstrating that (1) the Mann et al (1998) reconstruction is robust with respect to the elimination of any data that were infilled in the original analysis, (2) the main features of the Mann et al (1998) reconstruction are entirely insensitive to whether or not proxy data networks are represented by PCA, (3) the putative ?correction? by McIntyre and McKitrick, which argues for anomalous 15th century warmth (in contradiction to all other known reconstructions), is an artifact of the censoring by the authors of key proxy data in the original Mann et al (1998) dataset, and finally, (4) Unlike the original Mann et al (1998) reconstruction, the so-called ?correction? by McIntyre and McKitrick fails statistical verification exercises, rendering it statistically meaningless and unworthy of discussion in the legitimate scientific literature.

The claims of McIntyre and McKitrick have now been further discredited in the peer-reviewed scientific literature, in a paper to appear in the American Meteorological Society journal, "Journal of Climate" by Rutherford and colleagues (2004) [and by yet another paper by an independent set of authors that is currently "under review" and thus cannot yet be cited--more on this soon!]. Rutherford et al (2004) demonstrate nearly identical results to those of MBH98, using the same proxy dataset as Mann et al (1998) but addressing the issues of infilled/missing data raised by Mcintyre and McKitrick, and using an alternative climate field reconstruction (CFR) methodology that does not represent any proxy data networks by PCA at all.

References:

Cook, E.R., J. Esper, and R.D. D'Arrigo, Extra-tropical Northern Hemisphere land temperature variability over the past 1000 years, Quat. Sci. Rev., 23, 2063-2074, 2004.

Crowley, T.J., and T. Lowery, How Warm Was the Medieval Warm Period?, Ambio, 29, 51-54, 2000.

Esper, J., E.R. Cook and F.H. Schweingruber, Low-frequency signals in long tree-line chronologies for reconstructing past temperature variability, Science, 295, 2250-2253, 2002.

Jones, P.D., K.R. Briffa, T.P. Barnett and S.F.B. Tett, High-resolution palaeoclimatic records for the last millennium: Integration, interpretation and comparison with General Circulation Model control run temperatures, Holocene, 8, 455-471, 1998.

Jones, P.D., Mann, M.E., Climate Over Past Millennia, Reviews of Geophysics, 42, RG2002, doi: 10.1029/2003RG000143, 2004.

Mann, M.E., R.S. Bradley, and M.K. Hughes, Global-scale temperature patterns and climate forcing over the past six centuries, Nature, 392, 779-787, 1998.

Mann, M.E., R.S. Bradley, and M.K. Hughes, Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations, Geophysical Research Letters, 26, 759-762,
1999.

Mann, M.E., Ammann, C.M., Bradley, R.S., Briffa, K.R., Crowley, T.J., Hughes, M.K., Jones, P.D., Oppenheimer, M., Osborn, T.J., Overpeck, J.T., Rutherford, S., Trenberth, K.E., Wigley, T.M.L., On Past Temperatures and Anomalous Late 20th Century Warmth, Eos, 84, 256-258, 2003.

Rutherford, S., Mann, M.E., Osborn, T.J., Bradley, R.S., Briffa, K.R., Hughes, M.K., Jones, P.D., Proxy-based Northern Hemisphere Surface Temperature Reconstructions: Sensitivity to Methodology, Predictor Network, Target Season and Target Domain, Journal of Climate, in press, 2004.

Soon, W., and S. Baliunas, Proxy climatic and environmental changes over the past 1000 years, Climate Research, 23, 89-110, 2003.

Soon, W., S. Baliunas, C, Idso, S. Idso and D.R. Legates, Reconstructing climatic and environmental changes of the past 1000 years, Energy and Environment, 14, 233-296, 2003.

This is hard enough for people who know what the scientific method is. How are we supposed to expect Joe Public to figure it out?

That seems to be a contradiction on your lips.  Once again, I'm sorry if I'm being too confrontational, but your earlier assertions are those of a person who believes that he DOES know FOR A CERTAINTY what's going on, even though his informational sources are primarily propaganda in the popular media.  I do not expect Joe Public to figure it out, and I don't expect you to figure it out either... what I expect is for Joe Public to admit when he's out of his depth, and to trust the scientific community and its peer review process, which has little or nothing to do with what appears in the popular media as "science".

[error]

I don't have access to the information as to who chose them to testify. But I can tell you that the hearing was all about Climate Change and the Media. They also seemed to have the same number of people testifying that global warming is a man-made crisis of epic proportions. I can only imagine what the Senators thought of this. I can't wait to get a full transcript of this hearing; I wasn't able to quickly find any audio or video of it online. (Unfortunately it usually takes the bureaucrats six to nine MONTHS to produce a transcript.)

The full citation for the reference I posted above is:

Khilyuk, L.F. & Chilingar, G.V. 2006 On global forces of nature driving the Earth's climate. Are humans involved? Environmental Geology 50, 899-910.

Received: 18 August 2005  Accepted: 27 February 2006  Published online: 11 May 2006

Abstract  The authors identify and describe the following global forces of nature driving the Earth's climate: (1) solar radiation as a dominant external energy supplier to the Earth, (2) outgassing as a major supplier of gases to the World Ocean and the atmosphere, and, possibly, (3) microbial activities generating and consuming atmospheric gases at the interface of lithosphere and atmosphere. The writers provide quantitative estimates of the scope and extent of their corresponding effects on the Earth's climate. Quantitative comparison of the scope and extent of the forces of nature and anthropogenic influences on the Earth's climate is especially important at the time of broad-scale public debates on current global warming. The writers show that the human-induced climatic changes are negligible.

Now I can't say whether it is true or not, and I'm not quite ready to pay for a copy of the paper, but it does show there is disagreement as to whether and how much humans impact global warming.