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and Investigative Research; 9 June 2014; by Francisco Gil-White
Science thrives on debate, so a good way to gauge the strength of the anthropogenic global warming (AGW) hypothesis is to examine how its proponents reply to the challenge posed by the Antarctic ice-core evidence. This is what we do here.
█ RealClimate.org and the ice cores
█ Al Gore, Joe Barton, and the ice cores
█ Geoscientist Jeff Severinghaus replies to the ice core evidence
█ Severinghaus is confronted by his readers
“While some environmentalists might concede that the IPCC report is a political document, they would also point to what they see as Mr Gore’s knockout punch, a dramatic video based on the world’s climate record preserved in ice cores.”
--The Straits Times (Singapore) 
The anthropogenic global warming (AGW) hypothesis claims that current global warming is Man-made. Against the doubts expressed by skeptics, proponents of this hypothesis have presented the Antarctic ice-core evidence as their “knockout punch” (see quotation, above); according to proponents this evidence proves that, in times past, changes in CO2 concentrations have been responsible for major changes in temperature.
In his movie, An Inconvenient Truth, Al Gore posed in front of a giant representation of the ice core evidence, shown as two graphs, one of temperature levels and another of CO2 levels, covering a period of many hundreds of thousands of years.
Inconvenient Truth : Al Gore
posing with data from the Antarctic
The Straits Times:
“The two graphs obviously move in lockstep with each other, he says. With great panache, Mr Gore concludes that when carbon goes up, temperature inevitably follows.”
Literally, Al Gore says: “When there is more carbon dioxide, the temperature gets warmer.” But is that what happens? On Al Gore’s graph one cannot tell whether CO2 or temperature rises first. But in a more careful representation, as the The Straits Times explains,
“...if the graphs are mapped onto each other instead of being counterposed one above the other, as Mr Gore does, ...it becomes very clear that, very consistently, every temperature rise actually precedes the carbon [dioxide] rise by some 800 years. This undeniable time lag is critical since what it says is that more carbon in the air did not lead to global warming in times past. If so, factors other than carbon must have set off the various periods of global warming in times past.
If so, the most fundamental assumption of the carbon theory of human-induced global warming rests on shaky ground.”
Let’s summarize. The Antarctic ice-core record shows that, at every glacial termination, CO2 lags temperature: this is known as the ‘CO2 lag.’ So none of the major historical rises in temperature were caused by changes in CO2 concentrations. Rather, it appears that rises in temperature cause higher concentrations of CO2 (since CO2 rises after).
Does that make chemical sense? It does.
You may perform the following experiment at home. On a warm day, put a can of soda in the sun, and at the same time place an identical can of soda in the refrigerator.
Wait 3 hours, then place both cans on a table and open them. Wait 30 minutes and then perform a taste test of each. The question we wish to answer is: Which soda lost more gas? Answer: The hot soda.
Why? Because the gas in soda is CO2, and CO2 is more soluble in cold than in warm water. So as water heats, it releases CO2. It therefore makes perfect sense that as the planet heats, the oceans eventually release CO2 into the atmosphere, just as we see in the Antarctic ice-core evidence.
So is the ice-core evidence “Mr. Gore’s knockout punch”? Yes, but he’s the one getting punched.
Given the state of media discussion on global warming, one may feel insecure on this point. One might prefer, before making up one’s mind, to see partisans of the AGW hypothesis at least try to defend themselves from the ice-core evidence. After watching them fail, one could then abandon this theory without the nagging pangs of guilt that usually accompany shifts against political correctness.
RealClimate.org and the ice
I didn’t choose RealClimate at random. This website was created by scientists intimately and notably involved with the IPCC.
RealClimate heralds its academic authority in its header: “Climate Science from Climate Scientists.” The “About” section explains:
“RealClimate is a commentary site on climate science by working climate scientists for the interested public and journalists. We aim to provide a quick response to developing stories and provide the context sometimes missing in mainstream commentary. The discussion here is restricted to scientific topics and will not get involved in any political or economic implications of the science...” 
After such a strongly worded commitment to avoid politics and economic policy one is surprised to find, in a post dated April 2007, the heading: “THE LAG BETWEEN TEMPERATURE AND CO2. (GORE’S GOT IT RIGHT.)”
Naturally, an article on the ice core evidence should, as this one does, make reference in its title to the glaring problem: CO2 lags temperature. But if a politician selling worldwide economic reforms via anthropogenic warming arguments is embarrassed by his own ‘best’ evidence, or if he isn’t, what does that matter to climate scientists whose declared intention is to discuss the evidence without “get[ting] involved in any political or economic implications...”?
Anyway. But we learn from this, at least, that despite 650,000 years of data showing temperature rising before—not after—CO2, the article will defend the bravado claim that Al Gore is still right. Mind you, Gore can’t be right about the graph, for to speak of the CO2 lag is to concede that Gore read his enormous graph precisely backwards. What the author is saying is that, despite the CO2 lag, CO2 is still (somehow) the agent of world temperatures.
The author begins:
“When I give talks about climate change the question that comes up most frequently is this: ‘Doesn’t the relationship between CO2 and temperature in the ice core record show that temperature drives CO2, not the other way round?’ On the face of it, it sounds like a reasonable question.”
Notice: To wonder whether the most fundamental premise of the AGW hypothesis might not be wrong, when the purported cause turns out to be an effect, only “sounds... like a reasonable question.” So respect for the rules of logic and the principle of causality cannot animate this doubt; rather, explains the author, certain people “try to discredit Al Gore,” and so “it is one of the most popular claims made by the global warming deniers.”
I am stopped cold.
Most skeptics of AGW actually agree that global warming has been taking place (at least for the period 1979-1998). But even if we didn’t, if this is a scientific debate, why attack us with the epithet “global warming deniers”? Sounds a bit like “Holocaust deniers,” doesn’t it? People beyond the pale. Heretics.
I glance nervously back at the “About” page for reassurance that this website “will not get involved in any[thing] political,” and then I am slammed by the article’s next few sentences.
[Quote from RealClimate begins here]
[The troublesome question] got a particularly high profile airing a couple of weeks ago, when congressman Joe Barton brought it up to try to discredit Al Gore’s congressional testimony. Barton said:
“In your movie, you display a timeline of temperature and compared to CO2 levels over a 600,000-year period as reconstructed from ice core samples. You indicate that this is conclusive proof of the link of increased CO2 emissions and global warming. A closer examination of these facts reveals something entirely different. I have an article from Science magazine which I will put into the record at the appropriate time that explains that historically, a rise in CO2 concentrations did not precede a rise in temperatures, but actually lagged temperature by 200 to 1,000 years. CO2 levels went up after the temperature rose. The temperature appears to drive CO2, not vice versa. On this point, Mr. Vice President, you’re not just off a little. You’re totally wrong.”
Of course, those who’ve been paying attention will recognize that Gore is not wrong at all. This subject has been very well addressed in numerous places. Indeed, guest contributor Jeff Severinghaus addressed this in one of our very first RealClimate posts, way back in 2004.
[Quote from RealClimate ends here]
This combines an ad hominem attack with a browbeating recourse to authority: If you think that Gore is “wrong at all” because some people “try to discredit” him with his own ‘best’ evidence then you have not “been paying attention” to how “this subject has been very well addressed in numerous places.” You are distracted.
Don’t be intimidated by this. We’ll
get to Jeff Severinghaus (below). But first let’s see how Al Gore
replied to Joe Barton.
Al Gore, Joe Barton, and the
Congressman Joe Barton (left) questions Al Gore (right)
First, Al Gore took refuge in authority: “...the [congressional] committees should be under no illusion of what the scientific consensus is...” Every national academy of science in the world, he insisted, endorses his views (this is false). He placed great emphasis on the IPCC, which he called “the most extensive and elaborate, in depth, highest quality, international scientific collaboration in all of history” (this is also false). For good measure, Al Gore compared believing in AGW to believing in gravity!
Al Gore then rattled off on the greenhouse effect and the lower part of the atmosphere, he disparaged as “magic” the notion that the sun might be responsible for planetary temperatures, and insisted that since the stratosphere gets cooler while the troposphere gets warmer (he seemed a bit unsure on this...) then he must be right.
At long last he turned to Barton’s point, which was about the Antarctic ice-core evidence. Said Gore: “On CO2 and temperature, when CO2 goes up, temperature goes up.” Notice the order: first CO2, then the temperature. He did the same in An Inconvenient Truth, when he posed before a gigantic graph of the ice-core data and said: “when there is more carbon dioxide, the temperature gets warmer.”
Not so. It’s the other way around: when temperature gets warmer, then we get more carbon dioxide: CO2 increases follow temperature increases.
After this, Gore insisted passionately that “The planet has a fever” and followed with a moral argument: “If the crib’s on fire you don’t speculate that the baby is flame retardant… You take action,” implicitly calling Barton a ‘baby killer.’ For good measure, Gore insisted that anybody who disagrees with him is reading a “science fiction novel.”
Then he returned to the substance of Barton’s point:
“In the ice core record, as I’ve said every time I give my slide show, the relation...—it’s a coupled system, they [CO2 and temperature] go up and down together...”
Notice: Gore almost made an explicit statement about the causal relationship but corrected course just in time: “it’s a coupled system.” Well yes. It is. Nobody said it wasn’t “coupled.” But as Barton pointed out the temperature rises first. CO2 rises after (with, on average, an 800-year lag).
After this, more virtuoso ink-spilling from Gore on rotation wobbles, orbits, the sun, the glacial-interglacial turns, all of it beside the point. Barton watched in silence and then simplemindedly insisted: “The temperature goes up before the CO2 goes up.”
Gore shot back: “Sometimes that has
been true in the past; the opposite has also been true in the past.” This is false. The
ice core data show that temperature
rises before CO2 at every glacial
Geoscientist Jeff Severinghaus
replies to the ice
Gore did not ably defend his pet hypothesis. But perhaps the professional IPCC climate scientists who contribute their views on RealClimate can do better? You’ll remember from the post quoted above:
“Of course, those who’ve been paying attention will recognize that Gore is not wrong at all. This subject has been very well addressed in numerous places. Indeed, guest contributor Jeff Severinghaus addressed this in one of our very first RealClimate posts, way back in 2004.”
Jeff Severinghaus is Professor of Geosciences at the Scripps Institution of Oceanography, University of California (San Diego). He is one of the scientists responsible for documenting the CO2 lag by studying the Antarctic ice cores. So we can hardly pick a better candidate to defend the AGW hypothesis from the ice-core evidence. If Severinghaus cannot do it, the AGW hypothesis is in trouble.
[Quote from RealClimate begins here]
This is an issue that is often misunderstood in the public sphere and media, so it is worth spending some time to explain it and clarify it. At least three careful ice core studies have shown that CO2 starts to rise about 800 years (600-1000 years) after Antantarctic temperature during glacial terminations. These terminations are pronounced warming periods that mark the ends of the ice ages that happen every 100,000 years or so.
Does this prove that CO2 doesn’t cause global warming? The answer is no.
The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend. The other 4200 years of warming could in fact have been caused by CO2, as far as we can tell from this ice core data.
The 4200 years of warming make up about 5/6 of the total warming. So CO2 could have caused the last 5/6 of the warming, but could not have caused the first 1/6 of the warming.
It comes as no surprise that other factors besides CO2 affect climate. Changes in the amount of summer sunshine, due to changes in the Earth’s orbit around the sun that happen every 21,000 years, have long been known to affect the comings and goings of ice ages. Atlantic ocean circulation slowdowns are thought to warm Antarctica, also.
From studying all the available data (not just ice cores), the probable sequence of events at a termination goes something like this. Some (currently unknown) process causes Antarctica and the surrounding ocean to warm. This process also causes CO2 to start rising, about 800 years later. Then CO2 further warms the whole planet, because of its heat-trapping properties. This leads to even further CO2 release. So CO2 during ice ages should be thought of as a “feedback”, much like the feedback that results from putting a microphone too near to a loudspeaker.
In other words, CO2 does not initiate the warmings, but acts as an amplifier once they are underway. From model estimates, CO2 (along with other greenhouse gases CH4 and N2O) causes about half of the full glacial-to-interglacial warming.
So, in summary, the lag of CO2 behind temperature doesn’t tell us much about global warming. (But it may give us a very interesting clue about why CO2 rises at the ends of ice ages. The 800-year lag is about the amount of time required to flush out the deep ocean through natural ocean currents. So CO2 might be stored in the deep ocean during ice ages, and then get released when the climate warms.)
[Quote from RealClimate ends here]
At the end of an ice age, each time, the warming begins first, and CO2 levels do not rise until about 800 years later. Severinghaus concludes that rising levels of CO2 cannot be the cause of warming during those first 800 years.
I agree. No other conclusion is indeed possible (not without rewriting the rules of logic or the principle of causality).
Some other cause, then (not CO2), must be responsible for ending the ice age. Severinghaus writes:
“It comes as no surprise that other factors besides CO2 affect climate. Changes in the amount of summer sunshine, due to changes in the Earth’s orbit around the sun that happen every 21,000 years, have long been known to affect the comings and goings of ice ages. Atlantic ocean circulation slowdowns are thought to warm Antarctica, also.”
Notice: powerful forces unrelated to CO2—and powerful enough to end ice ages!—are drivers of global temperatures. Though Severinghaus immediately afterward says that “Some (currently unknown) process causes Antarctica and the surrounding ocean to warm,” it appears from the above that the mysterious “unknown” process might be the sun. “This process,” Severinghaus agrees, “also causes CO2 to start rising, about 800 years later.”
He poses the obvious question: “Does this prove that CO2 doesn’t cause global warming?” One is tempted to answer (perhaps timidly) “yes.” But Severinghaus replies, “The answer is no.” And why not?
“The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend. The other 4200 years of warming could in fact have been caused by CO2, as far as we can tell from this ice core data.”
Can we conclude from the above that the ice-core embarrassment has been “very well addressed,” so that anybody thinking that Al Gore is “wrong at all” has not “been paying attention”? I hardly think so.
Severinghaus himself makes clear that his conjecture is entirely speculative: “The other 4200 years of warming could in fact have been caused by CO2.” Could. Grant, for the sake of argument, this very weak claim of in-principle possibility. Does anything compel you to say it is likely? Even to those overflowing with charity for Severinghaus his argument must seem baroque and full of special pleading.
The objections are obvious. If some powerful cause (powerful enough to end ice ages!) warms the planet for a full 800 years without any help from CO2, then why can’t the entire 5000-year trend be entirely due to this other, so powerful cause? And why isn’t this the first hypothesis?
What is it that compels Severinghaus to assert that when CO2 is finally released (after 800 years) it then takes over to “amplify” the warming? It is this:
“From model estimates, CO2 (along with other greenhouse gases CH4 and N2O) causes about half of the full glacial-to-interglacial warming.”
Model estimates? What are those?
Severinghaus is talking about computer simulations (= ‘models’) built by IPCC scientists. In these, when the simulated CO2 rises, it makes the simulated temperature rise—through a simulated ‘greenhouse effect’—in the simulated Earth.
Could other kinds of models be built? In principle, yes. But as astrophysicist Lowell Wood explains (quoted in Levitt & Dubner’s Super Freakonomics), nobody wants to be the ‘outlier’ in the climate-modeling business:
“ ‘Everybody turns their knobs’—that is, adjusts the control parameters and coefficients of their models—‘so they aren’t the outlier...’ ”
What is an ‘outlier’? An outlier is a model far from the norm. The norm here is composed of models that show ‘proper’ CO2-driven global warming.
But why doesn’t anybody want to be the ‘outlier’?
“ ‘[B]ecause the outlying model is going to have difficulty getting funded.’ In other words, the economic reality of research funding, rather than a disinterested and uncoordinated scientific consensus, leads the models to approximately match one another.”
Climate simulations—though still tremendously crude—require unbelievably expensive supercomputers. Scientists never have that kind of money, so they must get it from somewhere. This means making the people with the money happy.
Who are the people with the money? Those running the Western governments (the same governments that compose the Intergovernmental Panel on Climate Change, or IPCC). And what makes them happy? Hearing that CO2 causes global warming.
Thus, in order to build their simulations, climate modelers have to include assumptions (“parameters and coefficients”) that will make CO2 the king of planetary temperatures.
Is this corruption? We address this question in Part 6, but for now, consider this: as documented by US Senator James Inholfe, the ratio of dollars for scientists who support the AGW hypothesis versus skeptics is “$50 BILLION to a paltry $19 MILLION and some change.” A 3 to 1 ratio would already be quite worrisome. But this is off the charts: supporters of AGW get 2,632 dollars for every dollar that goes to a skeptic.
This appears to have affected all of climate science because climate science is in general horribly expensive. Result: “scientific consensus.”
The point is this: If we only build one kind of model, and then believe that CO2 causes global warming just because it does so in the models, we have a circular argument. The models were built to do that!
Most people don’t realize that a computer model or simulation—no matter how complex—is just a fancy way of representing a hypothesis. It is tremendously useful for exploring the implications of a hypothesis, and for testing its internal logic, but in the end it is still just a (complicated) expression of a hypothesis.
Even many scientists get this wrong, thinking that they have shown something about the world because they can make it happen in a simulation. But a hypothesis cannot—by itself—tell you what the world is like. You need to gather evidence.
For example, you need to trek to the Antarctic and drill for deep ice cores in order to obtain data about past atmospheric temperatures and past levels of CO2. If your model’s assumptions were reasonable, then your model will predict at least the qualitative shape of the data; if your assumptions are unreasonable, the data will contradict the model.
Or you can wait for new temperature fluctuations to tell you whether your model’s predictions are any good.
It’s called ‘doing science.’
When the data have been collected it is best to be honest. Who can doubt that if CO2 had risen first in the ice cores Severinghaus and colleagues would have shouted victory from the rooftops? Can you imagine their howls if skeptics, despite such evidence, had denied the global-warming role of CO2?
But it went the other way. So they tell us that CO2 causes global warming even though it begins rising after the temperatures do. Well, if the CO2-drives-global-temperature assumption is right no matter what the data say, then we ought to be saving ourselves tremendous expense and a lot of heroic trouble in the Antarctic.
When we assert—regardless of which way
the data go—that our model is right, then we have faith in the model,
just as people have faith in various kinds of supernatural causes even when the
evidence does not support their beliefs. Guided by such a mind-frame, we will
attack those who disagree with us for being “deniers” (“atheists”), and we
will accuse them of not “paying attention” to the Unquestioned Truth spoken
by those all-important greenhouse models—our new totems, our new idols.
Severinghaus is confronted by
Perhaps noticing the religious fervor, one reader of RealClimate, David Holland, commented:
“Wow! Are you really saying that we have no idea what starts to warm up our world from an ice age but [we] know with near certainty what has caused the warming of the last three decades?”
Put another way, if we don’t know yet why ice ages come to an end, shouldn’t we be a little less confident that we understand current global warming (especially when the ice core evidence does not support our AGW hypothesis)?
Another question: how can we build reasonable models of climate change that properly represent CO2’s proportionate role without factoring in the “unknown” powerful cause that ended ice ages?
This “unknown” powerful cause, as Severinghaus hints more than once, may well be the sun, and yet Victor Manuel Velasco Herrera, a researcher at the Institute of Geophysics of the National Autonomous University of Mexico (UNAM), points out that, incredibly, the models “do not include, for example, solar activity.”
Another reader of RealClimate, John (no last name is given), noticed that the ice core data already contain a test of Severinghaus’s claims, so he asked him about it.
I read your article “What does the lag of CO2 behind temperature in ice cores tell us about global warming?” You mention that CO2 does not initiate warmings, but may amplify warmings that are already underway. The obvious question comes up as to whether or not CO2 levels also lag periods when cooling begins after a warming cycle…even one of 5,000 years?
[. . .] If there is also a lag in CO2 levels behind a cooling period, then it appears that CO2 levels not only do not initiate warming periods but are also unrelated to the onset of cooling periods. It would appear that the actual CO2 levels are rather impotent as an amplifier either way…warming or cooling. [. . .]
If there is also a time lag upon the onset of cooling, then it appears that some other mechanism actually drives the temperature changes. So what is the time difference between CO2 levels during the onset of a cooling period at the end of a warming period and the time history of the temperature changes in the ice cores? 
[Excerpt from RealClimate ends here]
Remember: the AGW hypothesis claims that tiny increments in CO2 concentrations produce large changes in global temperatures. Surely, if this hypothesis is correct, the Earth cannot begin cooling before CO2 levels start coming down. In the Antarctic ice cores, therefore, we should see, at the beginning of cooling periods, that CO2 levels decrease first, followed by a drop in temperatures (as shown in the stylized diagram A).
But what if the ice cores show the following pattern: at the beginning of cooling periods the temperatures drop first, and then, after a lag, fall the levels of CO2 (as shown in stylized diagram B).
If the ice core data show the second pattern, reasons John, we don’t have any evidence to support that CO2 acts as an ‘amplifier.’ There would then be exactly zero evidence in the ice-core record to support the AGW’s most fundamental assumption. It would be reasonable to conclude, in such a case, that CO2 is “impotent.”
So what’s the story? What do 650,000 years of ice core data say about the final phase of warming trends? Jeff Severinghaus replies:
The coolings appear to be caused primarily and initially by increase in the Earth-Sun distance during northern hemisphere summer, due to changes in the Earth’s orbit. As the orbit is not round, but elliptical, sunshine is weaker during some parts of the year than others. This is the so-called Milankovitch hypothesis, which you may have heard about. Just as in the warmings, CO2 lags the coolings by a thousand years or so, in some cases as much as three thousand years.”
What causes a cooling trend to start? Once again most probably the sun. I didn’t say it. Severinghaus did. The temperature drops first, and CO2 levels then begin decreasing “in some cases as much as three thousand years [later].”
But does Severinghaus recant? Not for a second. He writes:
“But do not make the mistake of assuming that these warmings and coolings must have a single cause. It is well known that multiple factors are involved, including the change in planetary albedo, change in nitrous oxide concentration, change in methane concentration, and change in CO2 concentration.”
Is it really “well known” that
“warmings and coolings” have something to do with “change in CO2
concentration”? No. That only happens in the IPCC computer simulations. The
Antarctic ice-core evidence refutes those simulations.
Perhaps there is still some way to save the anthropogenic global warming hypothesis. I don’t know.
But I do know that, in reference to the Antarctic ice cores, RealClimate was wrong to say that “Gore’s Got It Right.” Gore got it precisely backwards.
I also know that Gore was wrong to call “ridiculous” anybody who disagrees with him that the Antarctic ice cores prove him right.
Speaking of which, what do you call selling the AGW hypothesis by making a movie with the Antarctic ice cores for climax?
But perhaps you are still unsure. After all, Al Gore is a politician. And though Jeff Severinghaus is certainly a relevant scientist, what we have examined here is a blog contribution. Fair enough.
Up next I take on the world’s most prestigious science journal: Nature.
and Further Reading
 “Who or what is the real culprit?; Not all experts agree that man is to blame; others point the finger at oceans or the sun.” The Straits Times (Singapore), May 1, 2007 Tuesday, REVIEW - OTHERS, 1625 words, Andy Ho, Senior Writer
 Ball, Tim (2014-01-17). The Deliberate Corruption of Climate Science (Kindle Locations 2835-2845). Stairway Press. Kindle Edition.
 The lag between temperature and CO2. (Gore’s got it
right.); RealClimate; 27 April 2007; by Eric
does the lag of CO2 behind temperature in ice cores tell us about global
warming?; RealClimate; 3 December 2004; by Jeff Severinghaus
 Levitt, S. D., and S. J. Dubner. 2009. Super Freakonomics: Global Cooling, Patriotic Prostitutes, and Why Suicide Bombers Should Buy Life Insurance. New York: HarperCollins.
 “O’Keefe and Kueter explain how a model works:
‘The climate model is run, using standard numerical modelling techniques, by calculating the changes indicated by the model’s equations over a short increment of time— 20 minutes in the most advanced GCMs— for one cell, then using the output of that cell as inputs for its neighboring cells. The process is repeated until the change in each cell around the globe has been calculated.’
Imagine the number of calculations necessary that even at computer speed of millions of calculations a second takes a long time. The run time is a major limitation. All of this takes huge amounts of computer capacity; running a full-scale GCM for a 100-year projection of future climate requires many months of time on the most advanced supercomputer . As a result, very few full-scale GCM projections are made.”
SOURCE: Ball, Tim (2014-01-17). The Deliberate Corruption of Climate Science (Kindle Locations 1380-1389). Stairway Press. Kindle Edition.
Climate Editorial Screed Violates Basic Standards of Journalism”; Senate
Committee on Environment and Public Works; August 5, 2007;
OF THE MOMENT; “Scientists abandon global warming 'lie' : 650 to dissent at
U.N. climate change conference”; World Net Daily; Posted: December 11, 2008
letter and Severinghaus’s response are both quoted in the first RealClimate
article mentioned in this piece. To read them, please go to the link and
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