A skeptical look at global warming
I decided to look into global
warming while teaching an Astronomy course in 2010.� Venus, Earth, and Mars have differences in
temperature that cannot be simply explained by their relative distances from
the Sun.� Venus has a �runaway�
greenhouse effect, while Mars has very little greenhouse warming because it has
very little atmosphere.� Then I had to
tell them the �inconvenient truth�:� I am as clueless as anyone regarding the
highly politicized debate about global warming.
Footnote: Physics majors might want to
see my actual calculation of the Martian greenhouse effect (smallfiles01\Stefan.pdf).� It was my intention to perform such simple
calculations to get a handle on the various claims made about global
warming.� (And, I later found that such
simple calculations have already been performed � see Section 7 below.)
Note to the Reader: �I would greatly
appreciate your comments.� Send them
to [email protected] and let the subject be skeptical.�
Contents
1-Skepticism is a choice, not a judgement
2-Is Global Warming a house of
cards?
4-Finding a testable �consensus� view
5-Don�t believe most global warming skeptics
6-The search for credible skeptics continues
7-Climategate and the Hockey Stick (tree ring) controversy
9-Misunderstanding the �Confidence Interval�
10-Opportunities for amateur research
11-Conclusion
1-Skepticism is a choice, not
a judgement
I choose to remain skeptical on global warming, regardless of what
the evidence says.� I once spent over a decade in complete frustration,
trying to be an �expert� in the teaching of math and science.� Many of my colleagues had gone beyond the investigation of teaching methods, and
on to implementation of reform.� The sad part is that I am still intrigued by
some of these ideas, and fear that important aspects of education reform will
never be implemented because insufficient or unconvincing evidence was
presented.� Carefully constructed and
repeatable experiments are possible in the field of math/science pedagogy, but
my efforts to encourage such research were not appreciated by colleagues or
supervisors.� I noticed the skepticism
and resistance to change among teachers � at both the college and precollege
levels � and reasoned that we needed a simple way to convince the
skeptics.� I found the published papers
in the field hopelessly unconvincing, full of subjective observations and
carefully selected diagnostic �pre-tests� and �post-tests�.�
2-Is Global Warming a house of cards?
One critic of global warming
asserted that global warming is a �like a religion�, but I prefer words like �groupthink� or �confirmation bias�.� The scientific house of cards typically starts with a seminal paper.� Like ALL papers, this seminal paper is
slightly flawed. Other papers follow that lean on this and other papers. It is
only when the house of cards is built to some height can it be tested in an
interesting way.� Such testing of a
theory requires time, and some could argue that global warming is too urgent
for the �test of time�.� Unfortunately
the political fact is that massive large-scale efforts to deal with global
warming are unlikely until the theory is fully tested, confirmed, and believed
by almost everybody.
I tend not to believe in
large-scale and outrageous conspiracies.�
If somebody helped Oswald kill Kennedy, then it was a tiny group that
remarkably managed to keep a big secret.�
Organizations like the FBI, CIA, KGB, or even the Mafia would be unable
to keep such an event under wraps.� If
thousands, or even just hundreds, of scientists are deliberately hiding
something, two things would happen:�
First, there would be a number of disgruntled whistle-blowers.� Second, the leaders of this infamous group
would begin to feud with each other.�
Scoundrels are notoriously poor at cooperating.� Therefore, my skepticism is more focused on
unintentional biases than cynical fraud.
I have found Wikipedia to be
a reliable source of information about science and therefore used it to look up
�Global Warming� (smallfiles01/100216wiki.pdf).� Wikipedia�s article on �Climate Sensitivity�
(smallfiles01/100216wiki_sensitivity.pdf)
was helpful, as well as link from Wikipedia to lengthy article by Stefan Rahmstorf that strongly supports the consensus view.� (see smallfiles01/Rahmstorf_Zedillo_2008.pdf)� It is nearly impossible to read a technical
report and judge its merits, though an experienced person can often skim an
article to ascertain that it written by a �quack� who only pretends to be a
scientist.� Both the quality of scientific
writing and inspection of his publication record indicate that Rahmstorf is no �quack�.��
But as I already stated, we should not immediately eliminate the
possibility of �groupthink�.
Wikipedia does not present a
strong case against global warming, but this is appropriate, since an encyclopedia
is expected to favor the consensus opinion.�
Wikipedia does describe the controversy in some detail, and even
includes a list of prominent skeptics (smallfiles01/100216wikiskeptics.pdf)
along with brief summaries of their objections.�� One complication in this debate is that
neither the �skeptical� nor �consensus� views are well defined.�� Before exploring any alternative view put
forth by �skeptics�, I need to learn more about the �consensus� and attempt to
educate myself as to why this view exists.��
2/18/2010. (later edited)
4-Finding a testable �consensus� view
Since there is no unique
�consensus� view, I should look for one appropriate to an investigation that is
committed to neutrality.� In other words,
I seek a �consensus� view that can be tested.�
A website on global warming that ranks high on Google is sponsored by
the American Institute of Physics (smallfiles01/100218aip_history.pdf).� The Summary link at (http://www.aip.org/history/climate/summary.htm)
on this contains the following graph, taken from a 2009 article by Lean and
Rind (see smallfiles01/100218LeanRind.pdf):
�click to enlarge smallfiles01/100218aipRindLeanTemp.jpg
As illustrated, Lean and Rind
predict a temperature rise of 0.17 plus or
minus 0.03 degrees centigrade per decade, provided we ignore the influences
of:
�
The El Ninos
and La Ninas that almost randomly change the
temperature by about 0.1C to 0.2C each year.
�
Volcanoes that can drop the
temperature by up to 0.2C for a couple of years (If it�s is super-volcano, then
all bets are off!)
�
The solar radiation variation
(associated with Sunspots) that can add or subtract about 0.05C.
I looked at the references to
this article and they seem OK.� What I
like best about this quasi-prediction is that we should be able to test it in
just a few decades.�� It is worth noting
that Rind and Lean do not claim to actually �predict� the weather over the next
few decades, but instead make a precise and testable prediction as to how
average temperatures will be correlated with unpredictable events (El Ninos and volcanoes)��
The temperature rise claimed by Lean and Rind
is consistent with statements made by the IPCC.�
2/20/2010
5-Don�t believe most Global
Warming Skeptics
On the day I went to Google,
the top skeptical website was globalwarming.org ( s03\googleGlobWarmOrg.pdf ).� Looking for skeptics who were also highly
regarded scientists, I was intrigued by a statement that nearly half of seven
Nobel Prize laureates in a panel discussion at Lindau
were skeptics (see the top of page 2 of s03\halfnobelmyth.pdf
and the first line of s03/cryptoskpetic.pdf).� I copied an audio file
(stored as Lindau_AUDIO.m4a but often removed
due to its large size).� An honest
summary of the discussion was written by Christina Reed (s03\nobelsummary.pdf).� The only true �global warming skeptic� was
Giaever.� There was a general consensus
among the others that the real problem is not CO2 per se, but rather that we need to find a sustainable source of
energy.� I believe it was the same
website (globalwarming.org) that led me to a claim that someone had published
�proof� in a refereed journal that
global warming was false (s03\FalseReference.pdf).� I looked at actual the paper and saw at the
top of the page that the article was unrefereed (s03\notreviewedAps.pdf).� These
blatant factual errors should be a warning to anybody who gets their
information from the internet.
Even FOX news can�t seem to
get it right. �When I saw a something on
FOX news about Al Gore, I found the transcripts on (s04\foxGoreWhopper.pdf), which claimed Al
Gore had told a �whopper�.� The links on
that page went nowhere, but I finally traced the �evidence� that Al Gore
misrepresented a statement by NOAA, by googling the
words that the website had attributed to NOAA.�
The actual NOAA website tells a completely different story, as the
reader can verify be reading s04\noaaprecipitationreport.pdf.�� This graph makes it clear that NOAA has
reported extra moisture in the American northeast:�
click to
enlarge s04\noaa.gif.�
I do not like it when Al Gore
or anybody else tries to link this year�s weather to climate change.� Such talk is highly misleading.� But when Al Gore says something silly, it should
be reported as �silly� and not as a �whopper� (defined in Wikipedia as s04\wikiwhoper.pdf).� Where I come from, you don�t call somebody a
liar when they repeat a statement made by the National Oceanic and Atmospheric
Administration.
Even when FOX news reports
the truth, something is fishy.� Page one
of Bret Baier�s transcript s04\baierflower.pdf documents that he suddenly
reported that a �scientist� has raised concerns that global warming will cause
flowers to lose their smell.� No climate
scientist in his or her right mind would raise such an issue.� If anything, global warming will allow
flowers to bloom everywhere!� I managed
to trace all this to comments made by people in Malaysia s04\malaysiaflower.pdf.� Of all the science stories to slip into the
daily news broadcast, why did FOX pick this one?
But the
other side is also capable of misleading the public:�
For example, one so-called �warmist� website illustrates the importance fossil fuel
combustion with the following figure:
�click
to enlarge s03\checkbook.png
This fails to inform the
unwary reader that nature plays a far greater role than humans do in the carbon
cycle and balance of atmospheric CO2:
�� click
to enlarge�� s03\Carboncycle.gif�� (3/24/2010)
6-The search for credible
skeptics continues�
My wild goose chase for Nobel
Prize winning skeptics was not motivated by hero worship for those who have won
such prizes.� I searched for this elusive
(and ultimately nonexistent) panel of skeptics because I was seeking small
population of scientists from which an unbiased sample might be collected.� Senator Inhofe and other have produced lists
of scientists who are skeptical about global warming.� While some of the names on that list don�t
belong there, it is a mostly valid list.�
The problem with such lists is that there are even more scientists who
take the consensus view that anthropogenic effects are the primary cause of
global warming.� Peter Doran performed a
survey (s06\012009_Doran.pdf) that suggests
that most scientists at affiliated with universities and/or federal
laboratories hold the consensus view.�
Unfortunately, Doran�s database did not include scientists working for
oil companies � that would have been interesting, but Doran apparently had no
easy access to such a data base.� I did a
bit of a background check on Doran and discovered that he had provided evidence
that much of Antarctica was warming, and therefore is one of many people who
have �blown a whistle�, yet continue to hold to some form of the consensus
view. (Other people who seem to have �blown a whistle� yet remained in the
�club� include Cogley and Briffa,
as discussed below.)
click to
enlarge s07\survey.jpg
The fact that the scientific consensus
supports the anthropogenic theory global warming cannot be disputed.� Consider, for example, the simple but
powerful claim made in Wikipedia: The finding that the climate has warmed in
recent decades and that human activities are already contributing adversely to
global climate change has been endorsed by every national science academy that
has issued a statement on climate change, including the science academies of
all of the major industrialized countries.
I explored the list of
skeptics found in Wikipedia, and many of them have impressive track records as
scientists.� Some, such as Fred Singer
and Richard Lindzen, have views on other subjects
that strike me as �odd�.� But nobody can
dispute their scientific accomplishments or expertise.� The arguments involved in the �hockey-stick�
debate between Mann, McIntyre and McKitrick have
become so technical that virtually nobody can master the intricate
mathematics.� So while McIntyre and McKitrick appear be �credible� skeptics, they are not
�understandable� skeptics.�
I think it is significant
that many of the �whistleblowers� in this field are �insiders� who maintain
largely consensus views on global warming, even after �blowing a whistle�.� A good example of this is the question of
whether the Himalayan glaciers are melting.�
These three websites, s05\HimGlacLal.pdf
, s05\himmalaySciMaglet.pdf , s05\himalayusnews.pdf , document that the �whistleblower�
Cogley also affirms that most glaciers are probably
in the process of melting.�� Another
example concerns the tree-ring divergence that played a central role in the �climategate� email story which erupted in November
2009.� This controversy was no secret
within the scientific community, as can be seen from the long list of
publications that investigated this problem prior to 2009:
click to
enlarge s06\treering.jpg
My investigation into two
news �scandles� (i.e. the climategate
emails on tree ring divergence, and the falsely reported melting rates of
Himalayan glaciers) has me convinced that the scientific process is more or
less self-correcting.� In both cases,
members of the scientific establishment played pivotal roles in investigating
or uncovering embarrassing facts, without �leaving the club�.�
On the other hand, I do fault
IPCC for not highlighting a problem with tree-ring
proxies when reporting the �spaghetti� version of the hockey-stick graph, which
is shown at the beginning of the next section:�
7-Climategate and the Hockey
Stick (tree ring) controversy
The climategate
�scandal� was largely centered on the black curve, which shows actual
thermometer measurements.� The colored
lines show various efforts to measure past temperatures by analyzing tree-ring
thicknesses.
� click
to enlarge s06\spagetti.jpg
What is not shown in the
figure above are any recent tree-ring estimates. Had they been shown, they
would not have captured the rise in temperature indicated by the black
line.� In other words, the tree-ring data
and the thermometer data �diverge� sometime between 1960 and 1980.� This divergence calls into question whether
we can use tree ring proxy data to estimate temperatures between the years 1000
and 1850 AD.�
This divergence is discussed in a paper by Wilson, et al, in (s08\Wilson_2007.pdf) and is depicted below:
� click to enlarge s08\divergencesmall.jpg
I find this subject nearly
impossible to analyze because much of it is about the character and motives of
individuals.� I can judge the skills of a
scientist by looking at his or her publication record.� But you can�t glean much about a people�s
scientific integrity by reading what is written by or about them.�
The diagram shown above
suggests that the divergence between modern tree-ring proxy temperatures and
actual thermometer measurements is about half a degree.� Briffa is one of
those who appeared to have �blown a whistle�, yet remained loyal to the �global
warming cause�.� His original (1998)
graph shows a much larger divergence of perhaps 1.5 degrees:
�click
to enlarge s08\briffa.jpg
The title of Briffa�s paper (see s08\Briffa_et_al.pdf)
is also interesting in that great pains seem to have been taken so as not to
offend those who believe that tree rings make good temperature proxies.� For two different assessments of the
scientific integrity of using tree-rings as proxies, see s08\Oxburgh.pdf and s08\Wegma.pdf.� (The latter analyzes the social issues
involved when scientists collaborate to achieve a �consensus�.)� I find it plausible that both assessments are
correct.�
8-Two credible skeptics
One of my favorite �credible
skeptics� is Syun-Ichi Akasofu,
who actually prefers not to be called a �skeptic�, but a �critic� of IPCC.� (see s06\Why_has.pdf) Debates
between �consensus� and�skeptical� scientists are
asymmetrical.�� The �consensus� writes
complicated papers, and the �skeptics� look for flaws by posing simple
plausibility arguments, and claiming that we know less than we think we know. �For example, Akasofu
offers a simple sketch of global temperature graphs that include variations
associated with ocean currents:
�click
to enlarge s06/littleiceagesmall.jpg
Akasofu suggests that present temperature rises might be a continuation of
a poorly understood trend that goes back to the Little Ice Age.� (See also his more detailed article s06\akasofu.LIAge.pdf).� Akasofu�s graph
(shown above) also contains a feature that is essential to understanding this
debate.� Notice that the computer models
(labeled IPCC predictions) show a change in slope in
the future that is more severe than has been seen in the past.� This almost exponential growth in future
temperature predictions is attributed to feedback mechanisms.� The most important and least understood is
probably water vapor and clouds:� As the
temperature rises, computer models predict a more humid Earth, which will cause
a sharper rise in temperature because water vapor is a greenhouse gas.�
If Akasofu
uses simple graphs, then Garth Paltridge uses a
simple formula based on the fact that our computer models rely on feedback
(such as water vapor).� (See s06\PALTRIDGE.pdf for an excerpt of his article) A
well known example of feedback occurs when a spokesperson is using a microphone
while standing too close to the loudspeaker. �Ambient noise in the system gets amplified and
then re-amplified as the signal again travels from the mike to the
loudspeaker.� As anybody who has
experienced this knows, it is not easy to predict when that loud ringing noise
will interrupt the person who is speaking.�
It is even more difficult to predict an unstable global climate.� Paltridge argues
that regardless of what the computer simulators believe, we cannot trust the
computers.
This difficulty in making
long-range predictions with unstable systems either is or should be understood
by everybody who is studying our climate.�
The aforementioned article by Lean
and Rind acknowledges this by focusing on short term predictions.� It is interesting that I was immediately led
to this article by the website sponsored by American Institute of Physics (http://www.aip.org).� Both the AIP and
the authors of that paper (Lean and Rind) have a healthy understanding of the role
of skepticism in science.� It is OK to be
a skeptic about global warming, and with the help of people like Lean and Rind,
we probably don�t need to wait much more than a decade to greatly clarify this
aspect of the debate.�
9-Misunderstanding the �Confidence
Interval�
I am irritated by way IPCC emphasizes �confidence interval� in their reports, not
because the phrase is being misused, but because it is apt to be misunderstood.
Whenever a number is reported in the scientific literature, the uncertainty
should also be reported.� Consider, for
example, the �hockey-stick� controversy.�
The gray regions in the figure below indicate a 95% confidence interval.�
��� s06\hockey1.jpg�
I maintain that no credible person would claim that they are 95%
certain that the actual globally averaged temperatures fell within this range
(of about � degree!) almost a thousand years ago.� I presume that this confidence interval indicates that the
examination of more tree samples would not likely extend the estimate outside
the grey shaded area.� Such a statement
can be established using probability and statistics.� But no amount of statistical analysis can
tell us whether or not it is possible to estimate past temperatures from tree
rings, because that is a question not of mathematics, but of biology. It would
be nice if scientists could report the actual odds of a given paper being
valid, but how could one possibly perform such a calculation?�
This is the conundrum of scientific uncertainty:� Common sense demands that the procedure for
declaring uncertainty be made in a completely objective way.� Only mathematical formulas can yield such objectivity.� Such formulas rely on a mathematical model,
and the only available mathematical model is the one proposed by the author(s).
Almost by its very nature, the
calculation of a Confidence Interval requires circular reasoning.
For one more example of what I don�t like about IPCC,
recall that the Lean and Rind paper
was written to address the fact that the decade ending in 2010 was not
particularly warm.� In the previous
decade, IPCC published the following graph:
�click
to enlarge s06\linearfit.jpg
It is hard to believe that people
with the mathematical sophistication to analyze tree-rings using principle
component analysis, would resort to a series of linear fits to suggest
exponential growth in temperature.� What
is especially embarrassing about this graph is that data from the subsequent
decade (2000-2010) shows a nearly flat temperature profile:
� click
to enlarge s07/SatTem.JPG
10-Opportunities for amateur
research
I am always looking for
research that students can do.� It must
be useful and have unknown outcome, or else I don�t call it research.� Since the hypotheses of confirmation-bias and conspiracy-to-get-funding
can never be ruled out, they must always be investigated � but certainly not by
professional climatologists!� Two simple
studies come to mind:
1. The Heat Island Effect can be investigated
by measuring temperatures in the vicinity of a medium sized town (s06\heatisland1.pdf , s06\heatisland2.pdf). Some have claimed that
this effect has biased estimates of global temperatures, since we tend to
measure temperatures in cities, not in the countryside.� I am convinced that a few studies by
independent high schools could allow us to estimate the magnitude of this
error.
2. An
even easier study for the amateur scientist would be to use the fact that
temperature data is also available on the internet for thousands of
cities.� Nowadays it would be very easy
to repeat a study such as this one: s06\bowlinggreenpaper.pdf.� This study suggests that there has not been
significant warming in Ohio.� I causally
investigated this and concluded that this inability to detect a warming trend
in Ohio might be due to the fact that Ohio is situated in a region of the
United States that has not warmed significantly.� Note the following chart:
click to enlarge s07\usmap.jpg�
(I neglected to document the source of this picture � perhaps NOAA?)
11-Conclusion
It has been
about a year since I worked on this, but nothing has changed
significantly.� It will take another 5-10
years before 2009 article by Lean and Rind can be checked out (smallfiles01/100218LeanRind.pdf).� But I thought about the asymmetric nature of
distortions when I looked at how Fox
news covered a news conference by Obama today, on July 15, 2011.