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—an hir series—
Historical and Investigative Research; 7
Dec 2009; by Francisco Gil-White If climate science exhibits system-wide
pathologies when the topic is global warming, there is no better place to
look for them than the world’s most prestigious science journal: Nature. We will show here that
something has gone terribly wrong with the peer review process at Nature.
█ Geology,
Antarctica, and Ice Cores █ What happened to the peer-review process at Nature? ▄
Models ▄ Fischer et al. (1999) ▄ The
aftermath █
Petit
unrepentant Introduction In terms of human health effects CO2
(carbon dioxide) is basically harmless. It is safe, for example, to consume
in considerable quantities in sodas. In terms of environmental effects CO2 is
highly beneficial, for all plant life feeds on CO2, and plant life supports
the entire food chain. CO2 is essential to all life on Earth. For some years
now, however, an argument has been put forth that CO2—the fountain of life—is
a pollutant. The
scientists at the IPCC (Intergovernmental Panel on Climate Change), a United
Nations body, have defended the anthropogenic (man-made) global warming (AGW)
hypothesis, according to which human
production of ‘greenhouse gases’—and mainly CO2—contributes dramatically to
raise the planet’s mean temperature. Since the IPCC considers higher
temperatures catastrophic for presumably fragile planetary systems and hence
for humans, the IPCC recommends a dramatic curbing of industrial activities
responsible for CO2 production. All of
this hangs on one—utterly
fundamental—assumption: the claim that changes in CO2 concentrations do in
fact significantly affect planetary temperatures. If this is false, then
human production of CO2 cannot be responsible for current temperatures, and
IPCC efforts to alter energy policy become groundless. The
study of Antarctic ice cores bears critically on this fundamental assumption.
This evidence, however, has been improperly presented to the public. Though
journalists have done a poor job, in truth they cannot be expected to do
better than the scientific journals, whose treatment of this issue has been
riddled with problems. Below I will explain why the Antarctic ice core
evidence is so important, and how this evidence has been handled in the
scientific journal Nature. I have
chosen to examine Nature because it
is the most prestigious scientific journal in the world. And I have chosen to
examine not just any paper published in Nature
but one that has been cited so many times to ‘support’ the AGW hypothesis
that “it is currently ranked at #3 among Geosciences papers published in the
past decade.” If there is trouble here, therefore, there will be trouble
elsewhere. In other words, what we find here is symptomatic, and highly
diagnostic, of certain pathologies in the climate science academic system
that mar the defense of the AGW hypothesis. As we
shall see, the effect of these rather striking pathologies has been to endow IPCC
policy prescriptions with underserved prestige. _____________________________________________________________ Geology, Antarctica, and Ice Cores Geologists
are historians: they hunt and dig for clues about the past in special
‘document archives’—sedimentary deposits in the Earth’s crust—and against
this backdrop elaborate competing biographies for Mother Earth. Those who
would reconstruct the story of Earth’s atmosphere look to Antarctica,
the supreme air archivist due to its punishing cold. Each
time it snows in Antarctica air bubbles are trapped, but since nothing melts,
snow forever falls on snow creating a vertical record of trapped bubbles with
the oldest at the bottom. Geologists drill into the Antarctic ice cap, pull
out long ice cores, and then analyze the bubbles in the successive layers to
reconstruct the evolution of the atmosphere. We can now tell the story of
changing gas concentrations and temperature (the latter inferred from certain
gas isotopes) going back 650,000 years.
This is an impressive scientific feat.[1] At
first the layers examined were relatively thick but they have become ever
finer, yielding a gain in resolution akin to how a mountain range changes in
appearance as you approach in your car—all sorts of things that were
invisible, or blended into each other, gradually acquire sharpness and
contrast. Naturally, your initial guesses may be shown to be false once you
arrive for a more intimate inspection. When
geologists first studied the famous Vostok ice cores from Antarctica their
vision was a bit blurry. Ian Plimer, Australia’s most famous geologist,
explains: “The initial analyses of the Vostok ice core used
samples at intervals of hundreds of years. The initial conclusions were that
high CO2 in the atmosphere led to high air temperatures.” Geologists
began looking from ‘far away’—with “samples at intervals of hundreds of years”—so
the movements of CO2 and temperature relative to each other were difficult to
distinguish. They certainly appeared to rise and fall close together, but the
picture was so blurry that one could not say with precision what was rising
first, whether CO2 or temperature. Those
who already were betting on the ‘anthropogenic’ global warming (AGW)
hypothesis—which claims that our production of CO2 is raising global
atmospheric temperatures—guessed that CO2 was rising first, as this would
confirm the hypothesis’ most fundamental assumption: that higher
concentrations of CO2 act powerfully to warm the planet. This is what the
public was told in a million news stories. But
later, explains Plimer, “with far more detailed measurements on the scale of
decades... it was shown that high air temperatures are followed
some 400 to 1000 years later by a high atmospheric CO2 content.1411,
1412 More recent work, using argon isotopes in Antarctic ice cores of
just one temperature rise, shows that CO2 increased 200 to 800 years after
that particular temperature rise.1413 During the last 420,000
years there have been massive temperature changes, and a rise in CO2
concentration follows air temperature increase by about 800 years and
it is only after a cooling event that CO2 decreases. This is no
surprise, as CO2 is more soluble in cold water than warm water.” [2] [my emphases] Plimer,
a prominent skeptic of the AGW hypothesis, is talking about a result known as
the “CO2 lag” : going back 650,000 years, we now find that, at the end of
every ice age, temperature invariably rises first, and then, hundreds
of years later rise the levels of CO2. Also, when the planet cools, CO2
levels follow much later, sometimes more than a thousand years later. Another
way of saying it is that changes in CO2 concentrations lag changes in the temperatures. Plimer
says this is “no surprise” because “CO2 is more soluble in cold water than
warm water,” and this is just basic chemistry. Ergo, heated water releases CO2. When—for whatever reason—the
planet gets warmer, after some time the oceans will release significant
quantities of CO2, and this is what we see in the ice-core record.
But the
AGW hypothesis requires higher atmospheric CO2 concentrations to be the cause—not the consequence—of rising
planetary temperatures. Therefore, defenders of this hypothesis may not
honestly present the Antarctic ice-core record, as evidence in support of AGW. Curiously, however,
this is precisely what Al Gore—and the IPCC scientists who advise him—have
done (Part 1). Ian
Plimer’s prose overflows with scientific references, which is why, halfway
through his book (this is only page 276 of 504) we are already on footnotes
1411, 1412, and 1413. These refer us to the following studies: 1411 Fischer, H., Wahlen, M., Smith, J., Mastroianni, D., &
Deck, B. (1999). Ice Core Records of Atmospheric CO2 Around the Last Three
Glacial Terminations. Science, 283, 1712 – 1714. 1412 Mudelsee,
M. (2001). The phase relations among atmospheric CO2 content, temperature and
global ice volume over the past 420 ka. Quaternary Science Reviews, 20,
583-589. 1413 Caillon,
N., Severinghaus, J., Jouzel, P., Barnola, J.-M., Kang, J., & Lipenkov,
V. Y. (2003). Timing of atmospheric C02 and Antarctic temperature changes
across Termination III. Science, 299, 1728-1731. The Fischer et al. (1999), published in Science,
was the first scientific study with sufficient resolution to show which
of the two variables of interest—temperature or CO2—was rising first at the
end of glacial periods, and it shows that temperature
rises first and CO2 follows. The other two studies count as ‘replications’ of
the Fischer et al., for they
independently reached the same conclusion.
Thus, we have here a confirmed result that is about as fundamental a
challenge to the anthropogenic hypothesis as can be had. Why isn’t the public aware of this? One
reason concerns geoscientist Jeff Severinghaus. You will notice he is the
second author in the last of the three papers listed above, so he is one of
the scientists responsible for documenting the CO2 lag. Despite this,
Severinghaus has written an opinion defending the view that the CO2 lag does
not matter (see Part 2); according to him, the IPCC is still
right: CO2 causes global warming. To the
average journalist, Severinghaus’s views on this point carry all the
authority of a scientist responsible for documenting the CO2 lag. If these
journalists were inclined (or were told) to defend the anthropogenic
hypothesis, they will be satisfied with Severinghaus’s statements, because he
is the expert. Severinghaus published his piece not in a scientific
peer-reviewed publication but, conveniently, in a high-profile blog called
RealClimate, which is controlled by IPCC scientists for the express purpose
of educating journalists (see Part 2). RealClimate
achieves its educational mission surpassingly well: such influential
publications as Newsweek and The Economist give RealClimate all
sorts of free publicity and defend it as a trustworthy source of information
(see Part 4 and Part 5). And so what the public learns is that
Al Gore and the IPCC are right, never mind the CO2 lag (assuming you were
even aware of it). And yet Severinghaus’s RealClimate contribution defies the
most elementary logic (see Part 2). Even a non-specialist journalist
should be able to see through it. It is
not merely through influential IPCC blogs set up to ‘educate’ journalists
that the CO2 lag has been swept under the rug. Let us take a look at the
scientific journal Nature, more prestigious than any other. If there
is trouble here, there will be trouble elsewhere. _____________________________________________________________ What happened to the peer-review process at Nature? As
mentioned above, the March 1999 Fischer et al. paper in Science demolished
the AGW hypothesis’ most fundamental assumption when it reported that CO2
levels always lag the great temperature changes. Just
two months later—that is to say, with the publishing speed of lightning—the journal Nature showcased a paper by Petit et al.
with the following for final, concluding paragraph: “…As judged from the Vostok record, the long, stable
Holocene is a unique feature of climate during the past 420 kyr [420,000
years], with possibly profound implications for evolution and the development
of civilizations. Finally,
CO2 and CH4 [methane] concentrations are strongly correlated with Antarctic
temperatures; this is because, overall, our results support the idea that
greenhouse gases have contributed significantly to the glacial–interglacial
change. This correlation, together with the uniquely elevated concentrations
of these gases today, is of relevance with respect to the continuing debate
on the future of Earth’s climate.”[3] The
paper itself is perfectly illegible to non-specialists. But the above
conclusion, and especially the portion I highlighted, is by comparison quite
easy to follow. Was this conclusion written so that others may quote it in
support of AGW? Let us call that my hypothesis. And let us take a closer look
at this prose (you may compare my analysis to that of CO2Science.) I begin
with the first part of Petit et. al.’s conclusion. They say: “…As judged from the Vostok record, the long, stable
Holocene is a unique feature of climate during the past 420 kyr [420,000
years], with possibly profound implications for evolution and the development
of civilizations.” The
Holocene (the geologic era that we are still inhabiting) has indeed been
climatically quite stable, and sure enough—not “possibly” but definitely (and
also quite obviously)—this has “profound implications for evolution and the
development of civilizations.” Why are the authors making such a big fuss
about a hardly novel point: that civilization developed because the Holocene
has been stable? Well, because this is of “relevance with respect to the
continuing debate on the future of Earth’s climate.” The two none-to-subtle
implications are: 1)
climate
change is the enemy of civilization; and 2)
to
preserve civilization we must protect the current climatic stability. But is
climate change really a bad thing for civilization? Not
necessarily. If you start out with a very cold planet, then warmer
temperatures will make things better for complex civilization (it’s hard to
jump-start complex civilization in an ice age). What
about the other way around? What is the worst thing that could happen if you
start out with a warm planet? An even warmer planet? No. Again, the worst
thing would be an ice age. So we
find that curiously omitted from the Petit et al. conclusion is the point
that our Holocene stability has been
warm. In a world awash with alarms about a planetary “fever,” omitting
this point will lead readers to conclude that preserving Holocene stability
means avoiding heat. Then
Petit et al. write: “Finally, [in the Vostok ice-core record,] CO2...
concentrations are strongly correlated with Antarctic temperatures; this is because, overall, our results support the idea that greenhouse
gases have contributed significantly to the glacial-interglacial change.” This
sentence ought to be displayed in a museum someday. The problems with it are
so serious, and so basic, that they bear a close examination. I shall take it
apart slowly and methodically, carefully highlighting each portion to assist
attention and concentration. First,
consider the claim that nobody disputes: “Finally, [in the Vostok ice-core record,] CO2... concentrations are strongly correlated with
Antarctic temperatures;
this is because, overall, our results support the
idea that greenhouse gases have contributed significantly to the
glacial-interglacial change.” It is
certainly true, as the authors write, that for the past 650,000 years CO2 and
temperature are strongly correlated on the scale of hundreds of years.
However, when we examine with a resolution on the scale of decades, what do
we find rising first, CO2 or temperature? The temperature. But
Petit et al. do not mention this. Neither do they mention it elsewhere in their (eminently quotable)
concluding paragraph. This is interesting, because any mention of the CO2 lag
would render quite obviously false that “greenhouse gases have
contributed significantly to the glacial–interglacial change [i.e. planetary
warmings].” Is this why they left it out? Now
look again: “Finally, [in the Vostok ice-core record,] CO2...
concentrations are strongly correlated with Antarctic temperatures; this is
because, overall, our results support
the idea that greenhouse gases have contributed significantly to the
glacial-interglacial change.” Which “results” are Petit et al. talking about? Petit at al. found a correlation in the
movements between CO2 and temperature. This was not new. The question is:
Does this correlation really “support the idea that greenhouse gases have
contributed significantly to the glacial-interglacial change” [i.e. to
planetary warmings]”? Not by itself, no. The
same correlation is equally consistent with the idea that so-called
greenhouse gases are a consequence of
temperature rises, and not their cause. It depends on what rises first. And temperature (did I mention this?) rises first. So what Petit et al. write is false. Their
(redundant) results do not support the CO2-drives-temperature hypothesis. Now,
since
and
since
let us
make the relevant substitutions to understand this wondrous sentence better: “Finally, [in the Vostok ice-core record,] CO2...
concentrations are strongly correlated with Antarctic temperatures; this is because, overall, [the finding that CO2 and temperature are
correlated] support[s] [the IPCC’s most fundamental assumption].” So what
are the authors actually saying? Amazingly, this: That if government (IPCC = Intergovernmental Panel on Climate Change)
makes a claim, then Nature will behave in such a way as to confirm the
government. This
sort of thing can make me wonder if I haven’t suddenly been transported to
North Korea, or else it sends me rushing to my calendar (just to make sure
the year is not 1984). Now consider the sentence that follows,
which is the final and concluding sentence: “This correlation [between CO2 and temperature],
together with the uniquely elevated concentrations of these gases today, is
of relevance with respect to the continuing debate on the future of Earth’s
climate.” Translation:
Since the IPCC is right about the dangers of the “uniquely elevated concentrations of these gases today” we are best advised to follow IPCC recommendations. The
most elementary peer review, let alone the famously savage peer-review
supposedly practiced at Nature, should have eliminated—long
before press time—a concluding paragraph so riddled with incoherence,
illogic, bias, and Orwellian subterfuge as we have examined above. Models Let us
ask a pertinent question: On what basis do Petit et al. assert that
CO2 has anything to do with raising the planetary temperatures? Buried in
their paper is the following passage: “Results from
various climate simulations make it reasonable to assume that greenhouse gases have, at a
global scale, contributed significantly (possibly about half, that is, 2–3ºC)
to the globally averaged glacial–interglacial temperature change.” So it
is not the Vostok evidence—take good note—that in any way supports their view
that CO2 drives temperature. It is the “various climate simulations”—in other
words, the IPCC computer models. IPCC
scientists have produced computer models where simulated rises in CO2 make
the simulated temperature, in the simulated Earth, rise in the computer.
On the strength of those simulations Petit et al. state that it is
“reasonable to assume” that rises in real CO2 make the real temperature rise in the real Earth. This was also Jeff
Severinghaus’s argument when he defended the anthropogenic hypothesis from
the ice core embarrassment (Part 2). Once
again, the problem with this form of reasoning is serious, and also quite
basic. As pointed out in Part 2, in the computer models, simulated
rises in CO2 make the simulated temperature rise because of the assumptions
the programmers make. The models are built to do that. So what Petit et
al. are saying is basically this: It is reasonable to assume that CO2
drives temperature because we have assumed that CO2 drives temperature. That’s
called tautology or ‘circular reasoning.’ And it may be given the following
political translation: Al Gore and the IPCC are right because they are
right. (We
might as well go ahead and call them our ‘Dear Leaders’). Building
models is not in principle useless, but it is important to understand that a
model is the same thing as a hypothesis—it is just a very complex representation
of one. One needs to gather evidence from the world (e.g. Antarctic ice
cores) in order to see how well the hypothesis does. A hypothesis naturally
cannot confirm itself! Why
can’t the peer-review process at Nature catch such famously elementary
errors of logic?
Now let
us consider an obvious question: Did Petit et al. have anything to say
about the Fischer et al., which only two months earlier had
shown in Science that CO2 always lags temperature? Yes. Buried in a
paragraph elsewhere in the paper, they (hurriedly) commented as follows: “In a recent paper, Fischer et al. present a CO2
record, from Vostok core, spanning the past three glacial terminations. They
conclude that CO2 concentration increases lagged Antarctic warmings by 600 ±
400 years. However, considering the large gas-age/ice-age uncertainty (1,000
years, or even more if we consider the accumulation-rate uncertainty), we
feel that it is premature to infer the sign of the phase relationship between
CO2 and temperature at the start of terminations.” A
translation of the main message would be as follows: Fischer et al.
conclude that CO2 lags temperature every single time, but there is
“uncertainty,” and so they might be wrong. Of
course, anybody could be wrong. Petit et al. could also be wrong. So
could Al Gore. So could the IPCC. Scientists always start from here: the
presumption of everybody’s potential fallibility and the corollary obligation
of universal skepticism. The
point remains, however, that when Petit et al. published their paper
the only study with sufficient resolution to determine whether CO2 or
temperature rose first—the Fischer et
al.—concluded that at glacial terminations temperature always rises
first. And this contradicts the CO2-drives-temperature hypothesis. Since
this was the state of the art when Petit et al. published their paper,
it was dishonest for them to conclude as though Al Gore and the IPCC were necessarily
right because Fischer et al. might be wrong! The
laziest peer-review process should have caught this on first inspection. Now,
but what specific arguments are Petit et al. putting forth to say that
Fischer et al. might be wrong? They point to “the large gas-age/ice-age uncertainty (1,000 years, or
even more if we consider the accumulation-rate uncertainty).” Since
this uncertainty is so large, they say, it is “premature” to conclude that
CO2 lags temperature. What is
the “gas-age/ice-age uncertainty,” also known as the gas-age/ice-age difference? Imagine
snow falling on the surface of the Antarctic on 8 August 2010. As it falls,
it traps air, right? Not quite. Or not yet. Air will not be trapped
until a lot more snow falls on top, because the snowflakes are not initially
sufficiently compressed to prevent air circulation. Once there is enough
weight above, then this particular spot closes. So ice that fell in
the form of snowflakes on 8 August 2010 will end up trapping air from a later
date, because air circulation continues for a while. In
general, then, air in a particular segment of Antarctic ice cores will be
found in ice that is older than the air. How much older depends on a number
of things (it may be hundreds of years older).[4] This raises problems for our efforts
to date precisely such events as the onset and termination of glaciations. But
is this a problem for deciding whether temperature rises before or after CO2
in the Vostok ice-core record? I
cannot see how. For both the temperatures and the
concentrations of CO2 are estimated from the air bubbles, not from the
ice. As far as I can tell, it makes no difference to the CO2-lag result if
someone eliminates the gas-age/ice-age uncertainty. This is just an
obfuscation. Fischer et al. made a reference in their Science
paper to this very point: “The dating uncertainty (on
the order of 10,000 years for termination III) is considerable; however, the
absolute time scale is not so important as long as we consistently compare
Vostok CO2 with the Vostok isotope temperature record.” In
other words, our inability to determine how many years ago, exactly, a given
ice age ended does not affect our ability to determine whether, at this
termination, the CO2 or the temperature rises first. For this problem, the
“absolute time scale” is irrelevant, and we need merely to “compare Vostok
CO2 with the Vostok isotope temperature record,” both of them inferred from
the air bubbles, not the ice. Shouldn’t this be obvious? What
has happened to the peer-review process at Nature? Why
can’t the world’s premier science journal identify and reject so many
elementary problems of reasoning when the topic is evidence relevant to the
IPCC’s CO2-drives-temperature hypothesis? And why do Petit et al. commit such errors of reasoning
in the first place? Here is
one hypothesis: as we saw in Part 2, scientists may be tempted to toe the
line of the Inter-Governmental Panel on Climate Change’s (IPCC), because then
they receive 2,632 times more money from the governments organized in
the IPCC than do the skeptics. And
climate science is expensive.
In the
year 2003, J.-M. Barnola, D. Raynaud, C. Lorius, and N.I. Barkov, all of them
co-authors of the Petit et al. (1999) in Nature, authored a
report where they state the following: “at the beginning of the deglaciations, the CO2
increase either was in phase or lagged by less than ~1000 years with respect
to the Antarctic temperature, whereas it clearly lagged behind the
temperature at the onset of the glaciations.”[7] Translation:
In periods of global warming, CO2 either travels together with temperature
or else lags behind temperature, and in periods of global cooling, CO2
always lags behind temperature. These
co-authors of Petit are no longer comfortable saying that Fischer et al.
might be wrong: in 2003 they now agreed that CO2 never rises before
the temperature. Apparently they tried to soften the lag by stating that in
periods of global warming sometimes CO2 and temperature are “in phase” (i.e.
they rise together). Even should we grant this—that sometimes CO2 and
temperature rise at the same time—this still means that CO2 never
causes temperature increases (because that would require that CO2 rise first).
So Jean-Robert Petit’s co-authors are now agreeing that the Antarctic ice
core record contradicts the CO2-drives-temperature hypothesis (the Al
Gore/IPCC hypothesis). Why
haven’t you seen this on the front page of the New York Times? _____________________________________________________________ Petit unrepentant In
February 2007, Science Watch interviewed Dr. Jean-Robert Petit, first
author of the 1999 paper in Nature, about that very paper. The
magazine begins by explaining that “According to Essential Science
Indicators, this paper has been cited 967 times to date,” which is truly
astronomical, “and is currently ranked at #3 among Geosciences papers
published in the past decade.” The
Petit et al. has obviously done well, and in so doing has benefited
the Al Gore/IPCC juggernaut, despite the quiet about-face (examined above) of
some of its authors. Here
follows an excerpt of the interview with Petit: [Quote from the Science Watch interview begins
here] SCIENCE WATCH: What was the
significance of this [Nature 1999] paper for your field? PETIT: ...the greenhouse gases, by capturing
the infrared waves emitted by earth, prevent cooling and will play the role
of amplifier in the climate system. ...CO2 is an important actor in the
climate system. SCIENCE WATCH: In this paper, one of
your concluding remarks is that "Present-day atmospheric burdens of
these two important greenhouse gases [carbon dioxide and methane] seem to
have been unprecedented during the past 420,000 years." Would you please
elaborate on the implications of this statement? PETIT: With industrial development and
anthropologic activity, massive burning of fossil carbon as well as
intensification of agriculture released exponential amounts of CO2 and CH4
over the last 150 years. Present atmospheric composition well surpasses all
maximum concentrations from the ice records over the last 420 kyrs (30% more
CO2, 300% more CH4). This makes a permanent atmospheric cover over the globe
which prevents the natural cooling of the earth’s surface and making it so
the heat is always "on." A new climate equilibrium is expected but
we have no analog from the past climate (except maybe at the time of the
dinosaurs!). This raises questions for the future climate and the
consequences.[8] [Quote from the Science Watch interview ends
here] What
Jean-Robert Petit says in this interview is simply amazing. His research has
in no way, shape, or form—least of all the Petit et al. (1999) paper
in Nature—supported the view that
“greenhouse gases” are an important “amplifier in the climate system” and
“prevents the natural cooling of the earth’s surface and making it so the
heat is always ‘on.’ ” If any such claim had a chance of being true, then we
should see in the Vostok data that temperature levels go down after the
CO2 levels decrease. What in fact happens is that CO2 levels fall centuries
after the temperatures.
It is
precisely because Jean-Robert Petit’s research has not contributed one iota
of evidence to support the CO2-drives-temperature hypothesis that in his 1999
paper, the one cited 967 times, his reason for claiming that CO2 acts as an
amplifier was not the Vostok evidence
he was reporting but the IPCC computer models, as shown earlier. So if we
accept Petit’s judgment as first author that the “significance” of his paper
rests on that particular claim, then he has been cited 967 times simply for
saying that he has religious faith in the IPPC computer simulations. This is evidence of a pathology in the
academic system that is climate science. Simulations
are tools that help us represent and explore hypotheses, so they can only be correct if data about our real
world support them. The Vostok cores are evidence from the real world. They
refute the simulations. Why is
the climate-science system pretending otherwise?
_____________________________________________________________ Footnotes and Further Reading [1] Caillon, N.,
Severinghaus, J. P., Barnola, J.-M., Chapellaz, J. J., & Parrenin, F.
(2001). Estimation of temparature change and of gas age-ice age difference,
108 kyr B.P., at Vostok, Antartica. Journal of Geophysical Research, 106,
31,893-31,901. [2] Plimer, I. (2009). Heaven and Earth: Global Warming, the
Missing Science. New York: Taylor Trade Publishing. (p. ¿?) [3] Petit, J. R., Jouzel, J., Raynaud, D., Barkov, N. I., Barnola,
J.-M., Basile, I., Bender, M., Chappellaz, J., Davisk, M., Delaygue, G.,
Delmotte, M., Kotlyakov, V. M., Legrand, M., Lipenkov, V. Y., Lorius, C.,
Pépin, L., Ritz, C., Saltzmank, E., & Stievenard, M. (1999). Climate and
atmospheric history of the past 420,000 years from the Vostok ice core,
Antarctica. Nature, 399, 429-436. [4] Ice core | From Wikipedia, the free
encyclopedia [ Consulted 8 August 2010] “The
surface layer is snow in various forms, with air gaps between snowflakes. As
snow continues to accumulate, the buried snow is compressed and forms firn, a
grainy material with a texture similar to granulated sugar. Air gaps remain,
and some circulation of air continues. As snow accumulates above, the firn
continues to densify, and at some point the pores close off and the air is
trapped. Because the air continues to circulate until then, the ice age and the
age of the gas enclosed are not the same, and may differ by hundreds of
years.” [7] Barnola, J.-M.,
Raynaud, D., Lorius, C., & Barkov, N. I. (2003). Historical CO2 record
from the Vostok ice core. In Trends: A Compendium of Data on Global Change:
Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory,
U.S. Department of Energy, Oak Ridge, Tenn., U.S.A. [8] http://in-cites.com/papers/Jean-RobertPetit.html |
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