by Michael E. Mann, Huffington Post, September 24, 2012
If you're a science or math geek like me, you can't help but like Nate Silver. He's the fellow nerd who made good. His site FiveThirtyEight.com
is a must for any serious polling buff, and he regularly graces the
leading talk shows with his insightful if wonky commentary. So you can
imagine how excited I was a year ago when Nate's assistant contacted me,
indicating that he wanted to come to State College, PA -- the "happy
valley" -- to interview me for his new book on "forecasting and
prediction."
Nate, I was told, was working on a chapter about global warming. He
sought me out because he felt my expertise would make me an "excellent
guide to the history of climate modeling." He also expressed interest in
my own upcoming (since published) book The Hockey Stick and the Climate Wars
which details my experiences at the center of the climate change
debate. Needless to say, I was very much looking forward to the meeting.
And so it was on a crisp early November day that Nate arrived at my
office in the Walker Building of the Penn State campus. We exchanged
pleasantries and proceeded to engage in a vigorous, in-depth discussion
of everything from climate models and global warming to the role of
scientific uncertainty, and the campaign by industry front groups to
discredit climate science (something that is the focus of my own book).
As I saw Nate off, I insisted he sample the Penn State Creamery's famous
ice cream before leaving town. I tweeted excitedly about my meeting
with him, and by the end of the day Nate had even added me to his
relatively short list of twitter followees. Certain our discussion had
been productive and informative, I awaited Nate's book with great
anticipation.
And so I was rather crestfallen earlier this summer when I finally got a peek at a review copy of The Signal and the Noise: Why So Many Predictions Fail -- but Some Don't.
It's not that Nate revealed himself to be a climate change denier; He
accepts that human-caused climate change is real, and that it represents
a challenge and potential threat. But he falls victim to a fallacy that
has become all too common among those who view the issue through the
prism of economics rather than science. Nate conflates problems of
prediction in the realm of human behavior -- where there are no
fundamental governing "laws" and any "predictions" are potentially laden
with subjective and untestable assumptions -- with problems such as
climate change, which are governed by laws of physics, like the
greenhouse effect, that are true whether or not you choose to believe
them.
Nate devotes far too much space to the highly questionable claims of a
University of Pennsylvania marketing Professor named J. Scott
Armstrong. Armstrong made a name for himself in denialist circles back
in 2007 by denouncing climate models as having no predictive value at
all. Armstrong's arguments were fundamentally flawed, belied by a large
body of primary scientific literature -- with which Armstrong was
apparently unfamiliar -- demonstrating that climate model projections
clearly do in fact out-perform naive predictions which ignore the effect
of increasing greenhouse gas concentrations. As discussed in detail
by my RealClimate.org co-founder, NASA scientist Gavin Schmidt,
Armstrong simply didn't understand the science well enough to properly
interpret, let alone, assess, the predictive skill of climate model
predictions.
That Nate would parrot Armstrong's flawed arguments is a major
disappointment, especially because there are some obvious red flags that
even the most cursory research should have turned up. A simple check of
either SourceWatch or fossil fuel industry watchdog ExxonSecrets, reveals that Armstrong is a well-known climate change denier with close ties to fossil fuel industry front groups like the Heartland Institute, which earlier this year campaigned to compare people who accept the reality of climate change to the Unabomber, and secretly planned
to infiltrate elementary schools across the country with
industry-funded climate change denial propaganda. I suspect that Nate's
failing here arises from a sort of cultural bias. There is a whole
community of pundits with origins in economics and marketing who seem
more than happy to dismiss the laws of physics when they conflict with
their philosophy of an unregulated market. Nate may not share that
philosophy, but he was educated by those who do.
Nate Silver was trained in the Chicago School of Economics,
famously characterized by its philosophy of free market fundamentalism.
In addition to courses from Milton Friedman, Nate might very well have
taken a course from University of Chicago economist Steven Levitt, known
largely for his provocative 2005 book Freakonomics and its even more audacious 2009 sequel Super Freakonomics
-- a book that, perhaps better than any other, serves as a cautionary
tale of the dangers that lurk when academics attempt to draw sweeping
conclusions in fields well outside their area of training. In Super Freakonomics
as you might guess, Levitt drew questionable conclusions about climate
change and related energy issues based on an extrapolation of principles
of economics way, way, way, outside their domain of applicability. Even
some very basic physics calculations, for example, reveal that his
dismissal of solar energy as a viable alternative to fossil fuel energy
in combating climate change because of possible waste heat is total
nonsense. Ray Pierrehumbert, a chaired professor himself at the
University of Chicago in the Department of Geosciences, pointed this
and other serious errors out to Levitt in an open letter
that concluded with a campus map showing how easy it would have been
for Levitt to walk over to his office to discuss his ideas and,
presumably, avoid the serious pitfalls that ended up undermining much of
what he ended up saying in his book about climate change and energy
policy.
Unlike Levitt, Nate did talk to the scientists (I know. I'm one of
them!). But he didn't listen quite as carefully as he should have. When
it came to areas like climate change well outside his own expertise, he
to some extent fell into the same "one trick pony" trap that was the
downfall of Levitt (and arguably others like Malcolm Gladwell in The Tipping Point).
That is, he repeatedly invokes the alluring, but fundamentally unsound,
principle that simple ideas about forecasting and prediction from one
field, like economics, can readily be appropriated and applied to
completely different fields, without a solid grounding in the
principles, assumptions, and methods of those fields. It just doesn't
work that way (though Nate, to his credit, does at least allude to that
in his discussion of Armstrong's evaluation of climate forecasts).
As a result, Nate's chapter on climate change (Chapter 12: "A Climate
of Healthy Skepticism") is marred by straw man claims that don't stand
up to scrutiny. These include the assertion that (a) climate scientist
James Hansen's famous 1988 predictions overestimated global warming (they didn't),
that (b) "the Intergovernmental Panel on Climate Change (IPCC) settles
on just one forecast that is endorsed by the entire group" (pure
nonsense -- even the most casual reading of the IPCC reports reveals
that great care taken to emphasize the non-trivial spread among model predictions, and to denote regions where there is substantial disagreement
between the projections from different models), and that (c) "relatively
little is understood" about the El Nino cycle (here I imagine that Nate
might have misinterpreted our own discussion about the matter; I
explained in our discussion that there are still open questions about
how climate change will influence the El Nino phenomenon -- but that
hardly means that we know "relatively little" about the phenomenon
itself! In fact, we know quite a bit
about it). Finally, and perhaps most troubling (d) while Nate's chapter
title explicitly acknowledges the importance of distinguishing "signal"
from "noise" and Nate does gives this topic some lip service, he
repeatedly falls victim to the fallacy that tracking year-to-year
fluctuations in temperature (the noise) can tell us something about
predictions of global warming trends (the signal). They can't -- they really can't.
Nate's view of uncertainty, and its implications for climate model
predictions, is particularly misguided. He asserts that the projections
of the IPCC forecasts have been "too aggressive," but that is simply
wrong. It neglects that in many cases, e.g., as regards the alarming rate
of Arctic sea ice decline (we saw a new record low set just weeks ago), the climate models have been far too cautious; We are decades ahead of schedule
relative to what the models predicted. Uncertainty cuts both ways, and
in many respects -- be it the rapid decline in Arctic sea ice, or the
melting of the ice sheets -- it is cutting against us. Uncertainty, as
many economists recognize, is thus a reason for action, not inaction! I'm surprised someone as sharp as Nate just doesn't appear to get that.
Nate also takes some unnecessary cheap shots. In what has now become a
rite of passage for those looking to establish their "honest broker"
bona fides in the climate change debate, Nate makes the requisite "punch
the hippie" accusation that Al Gore exaggerated the science of climate
change in An Inconvenient Truth (a team of climate scientists reviewed the movie for accuracy and found that by-and-large Gore got the science right).
He characterizes climate scientist Gavin Schmidt as a "sarcastic"
individual who is unwilling to put his money where his mouth is by
betting his personal savings on his climate model predictions (this felt
to me reminiscent of Mitt Romney's widely mocked $10,000 bet challenge
to Rick Perry). And while I do appreciate some of the nice things Nate
says in the book about me personally (e.g., "Mann is exceptionally
thoughtful about the science behind global warming"), he at the same
time deeply misrepresents our discussion on several counts.
I had emphasized the importance of distinguishing the true
uncertainties in climate science (and there are plenty, e.g., the
influence of warming on hurricanes, how the El Nino phenomenon might be
affected, or how regional patterns of rainfall may change) from the
manufactured uncertainties and myths typically promoted by climate
change deniers and contrarians (e.g., "how come there has been no warming
since 1998?" -- the answer is that, of course, there has been).
I stressed how important it is, when scientists communicate to the
public, to make clear that while there are many details that are still
uncertain, the big picture (that humans are warming the planet and
changing the climate, and that far larger and potentially more dangerous
changes loom in our future if we don't act) is not.
Nate cherry-picks a single sound bite ("our statements [should not
be] so laden in uncertainty that no one even listens") to once again
reinforce the false narrative that scientists are understating
uncertainty. The point I was actually making was that we cannot spend so
much time talking about what we don't know, that we don't end up
telling the public what we do know. That, as Nate correctly quotes me,
"would be irresponsible." Nate states that "the more dramatic [climate
scientists'] claims, the more likely they [are] be quoted...," seemingly
implying that scientists have a motivation to overstate the science. He
ignores the fact that those scientists willing to feed the false
"scientists are exaggerating" narrative are the true darlings of the
"balance" over "objectivity" school of news reporting -- a school of thought that Nate sadly seems to have subscribed to.
Most disappointing to me of all was the false equivalence that Nate
draws between the scientific community's efforts to fight back against
intentional distortions and attacks by an industry-funded attack
machine, and the efforts of that attack machine itself. He characterizes
this simply as a battle between "consensus" scientists and "skeptical"
individuals, as if we're talking about two worthy adversaries in a
battle. This framing is flawed on multiple levels, not the least of
which is that those he calls "skeptics" are in fact typically no such
thing. There is a difference between honest skepticism -- something that
is not only valuable but necessary for the progress of science -- and
pseudo-skepticism, i.e., denialism posing as "skepticism" for the sake of
obscuring, rather than clarifying, what is known.
Nate deeply mischaracterizes an editorial published by the prestigious and staid journal Nature (whose sentiments are echoed in my book The Hockey Stick and the Climate Wars)
warning scientists that they "must acknowledge that they are in a
street fight, and that their relationship with the media really
matters." Nate grossly mischaracterizes the quote, claiming that "the
long-term goal of the street fight is to persuade the public and policy
makers about the urgency (or lack thereof) of action to combat climate
change." Nate makes it sound like the "street fight" was of the
scientists choosing, completely turning on its head what Nature
was actually talking about: scientists finding a better way to defend
science from cynical attacks whose sole aim is to confuse the public
about what we actually do know about climate change (and therefore
forestall any efforts to deal with it).
I could detail the numerous other problems with the chapter (and no
-- there aren't really 538 of them; I confess to having taken some
"poetic license" with the title of this commentary). But the real point
is that this book was a lost opportunity when it comes to the topic of
climate change. Nate could have applied his considerable acumen and
insight to shed light on this important topic. But the result was
instead a very mixed bag of otherwise useful commentary marred by
needless misconceptions and inappropriately laundered denialist memes.
Don't get me wrong. I'm still a FON (Fan Of Nate). I will continue to
follow his thoughtful commentary on all matters of politics and
polling. But when he makes claims about other topics, like climate
change, I think I'll be a lot more skeptical. Skepticism -- real
skepticism -- is, after all -- a good thing.
http://www.huffingtonpost.com/michael-e-mann/nate-silver-climate-change_b_1909482.html
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