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.
Follow Michael E. Mann on Twitter: www.twitter.com/MichaelEMann
From: lib.ru parkhom
Too bad most folks would never read it thru and actually follow along with the reasoning.
HadCRUT3 again. You just love using out-dated datasets that don't cover the entire planet, don't you? Let's try that one again, this time using a pair of truly global datasets:
GISS: --0.0002151ºC +/- 0.0029451 (S.E.) per year
UAH: +0.004816ºC +/- 0.003843 (S.E) per year
http://goo.gl/dpVI5
Looking at the two datasets, the differences between their trends is solely determined by the temperature spikes in 2002 and 2010. GISS shows a more pronounced spike in 2002, UAH a more pronounced spike in 2010. Of course, neither trend is statistically significant (GISS p-value = 0.9419, UAH p-value = 0.2122), so we'd need to add more data to see which trend is real. Of course, adding in 2000 or 1999 changes both trends to significantly positive, which doesn't fit your narrative.
Here is an example.
http://cdiac.ornl.gov/epubs/ndp/ushcn/ts.ushcn_anom25_diffs_urb-raw_pg.gif
http://dotearth.blogs.nytimes.com/2009/04/03/cool-spells-in-a-warming-world/
http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/
How deniers view global warming:
http://www.skepticalscience.com/graphics.php?g=47
I'm also curious as to why you're cherry-picking an old series that shows the lowest trend. HadCrut v4 is out, and its trend, which includes greater coverage in the far north, puts it more in line with the other data sets, such as GISS.
http://www.woodfortrees.org/plot/gistemp/from:2000/plot/gistemp/from:2000/trend
Also, remember that the end points (the last few years) include some sharp la Nina conditions, which will always suppress a trend.
Thanks for bringing it up !
--cold fronts don't last as long as they once did
--warm spells (even during winter) snap back faster with higher than normal rebounds
--During the cooling season nightime lows are higher, irrespective of daytime highs
--it costs less and less to heat and more and more to cool (even taking out the variable of fuel costs)
--record high temps are outpacing record lows by a five to one margin
--early fall snows are becoming more common
--early spring hot spots are becoming more common as well
--in the tornado belt, the times when local tornadoes develop has changed
--all of the above is playing havoc with world food production
Before you go off, just understand, not a scientist. The items above point to a type of change, or should I say, a change in pattern.
The climatologists have studied this subject more than anyone, and the climatologists are by and large telling us that it is getting warmer and that this warming is almost certainly caused by the combustion of fossil fuels. No fossil fuel funded statisticians are explaining the ever downward trend of the combined Arctic and Antarctic ice extent and volume. No fossil fuel funded statisticians are explaining why the stratosphere is cooling and the troposphere is warming. And no fossil fuel statistician is explaining why, instead of being in a Milankovitch cooling trend, the global climate is warming.
It sounds like Nate Silver may very well have damaged his creds on this one. The next few years will make it very clear to the public, in my opinion, who wins this contest. I wish for the sake of humanity that it would be Silver, but I think it will be Mann.
GISS"s temp anomaly was .33 now it is .51
Hansen's Scenario "B" [business as usual] predicted 1.0 by 2012.
So predicted warming 1 - .33 = .67
Actual warming .51 - .33 = .18
So he predicted 3.7 times more warming than happened . every year that it fails to warm the model fails worse.
When the prophets of doom and gloom cite his model as a reason to be concerned I laugh
http://www.realclimate.org/index.php/archives/2012/02/2011-updates-to-model-data-comparisons/
Hansen's model does run a bit warm, but only by about 1/3 (comparing the linear trends of actual data vs the Scenario B model). This can be ascribed mainly to its use of 4.2 C as a climate sensitivity estimate, rather than the 3 C best estimate the current consensus shows. The ocean heat lag might have been underestimated a bit as well.
What deniers miss is that Hansen's model has shown skill at predicting the future. Remember that the null hypothesis is no warming.
Lastly, recall that other Hansen projections have been spot on, or slight underestimates.
http://www.skepticalscience.com/Hansen-hit-a-home-run.html
First of all, your position is stated so poorly that I actually don’t really know what you are referring to. Hansen started his prediction back in 1984. He assumed a forcing of 4.2 degrees centigrade per doubling of the CO2 level and we now know that was high. Still, he did better than anyone else in 1984 at predicting what the temperature would be today. BTW, I think we were in a cooling trend when he made his prediction.
Hansen predicted a temperature rise of 0.28 degrees C plus or minus -.0.04 degrees c per decade way back in 1984. GISS gives 0.18 degrees C plus or minus 0.05 degrees C per decade for 2011. You may or may not have noticed, but 2012 is not over yet.
Hansen is still well within the error bars of his prediction, so I think he is doing pretty darn good. You can mock and call names all you want. So can I. The fact of the matter is you can’t name anyone who made a prediction in 1984 that comes even close to what Hansen did. Laugh all you want. It is healthy.
"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)."
You understand why "538," don't you?
Given that science denier blogs have convinced you into believing that the Moon violates the Laws of Physics* I can see how are deeply confused here too.
[ *Not a joke. Climate science denier sites really have convinced SecondTime -- and undoubtedly innumerable other so-called "skeptics" as well -- that the Moon violates the Laws of Physics. ]
"Atmospheric Chemistry and Physics: From Air Pollution to Climate Change"
John H. Seinfeld, Spyros N. Pandis
This is the standard graduate level climate text.
Think you know more than the scientists? Hah ha ha.
Yes, SecondTime does. Science denier sites have even convinced him that the Moon violates the laws of physics (no, really).
The other check on Dr. Mann's work, of course, is that the work of other scientists who have done their own climate reconstructions get results that are similar to Mann's (or more accurately, Mann and his collaborators.)
The denialist attack on Mann tries to take advantage of a naive public. Denialists have used emails stolen by criminals and a series of vicious smears to make Mann a target of hate. But Mann's reputation is secure among scientists and among people who understand his science.
CO2 -> oceans = acidification
It works just like in your soda pop. The ocean is getting fizzy.
People have been left to believe that there are two sides to everything - while that applies to society as a whole, it has no bearing in the natural sciences whatsoever.
If I jump off a 10 story building on this planet with solid pavement below, yes I'm going to be splattered all over the place when I collide with the ground - yes gravity is a theory, but the nomenclature of theory in the field of the natural sciences has a completely different meaning than from that of every day usage.
If I react hydrogen with oxygen I'm going to get water, blast that water with microwaves and it will start vibrating - aka get hot.
I don't know what the weather will be next month, but I'll wager you a billion dollars that if you live in the northern hemisphere it's going to get cold in december/janurary and hot July/August with the opposite being true if you're in the southern hemisphere.
See analysis by Lucia Liljegren at The Blackboard for decades starting in 1975 through 2003.
http://rankexploits.com/musings/2012/using-arma11-reject-ar4-projections-of-0-2-cdecade/
In the meantime, consider that in the last nine years, 5 trillion tons of land ice has melted and flown into the oceans. How much 'warming' does it take to melt that much ice? Enough to take a horizontal 'warming' and turn it significantly more vertical:
http://www.skepticalscience.com/pics/iceatmheat.png
And in any event, such short term trends are meaningless. It's quite amusing that there was such a hubbub in the denialosphere when Phil Jones agreed that the 15-year warming trend wasn't statistically significant, yet it never tires of trumpeting trends that are both much shorter and much less close to significance.
This sort of bland assertion is super-convincing.