Tag Archives: extreme weather events

Nate Silver falls off

In 2012, Nate Silver faced a conservative and media-led backlash for bringing rigor to election forecasting. His newly launched journalism project is now facing a backlash for failing to live up to its promise.

I am probably the ideal audience for Nate Silver’s new journalism project FiveThirtyEight.com. I am someone who values data in a frequently-substance-free world of reporting. Although I am an unabashed Sam Wang PEC partisan, I certainly appreciated Silver mainstreaming election forecasting based on factors other than wishful thinking and journalism biases towards “the horse race” and “momentum”. When Silver was attacked by know-nothings in the media and the conservative blogosphere, I cheered him on, and savored his election day vindication, anti-climatic as it was.

Rather than topping my “must read” list, however, the new FiveThirtyEight is something I won’t be reading. Here’s why:

I became aware of Silver’s imminent launch by his public Twitter announcement of two hires to cover science for his new venture: Emily Oster, a University of Chicago economist famous for counter-intuitive revelations (sound familiar?); and Roger Pielke Jr.

Image courtesy of Flickr user “ferdicam”, used under Creative Commons.

Now, I am not going to get into Roger’s pathological attacks on climate scientists. I am not going to get into his sweaty delusions of persecution. I am not going to get into Roger’s complete misunderstanding of elementary aspects of climate science. I am going to focus on just two things: what Nate Silver is known for, and what Roger Pielke Jr. is known for.

Nate Silver’s reputation is based on being a stats wiz. This is what his blogging was devoted to, what his best-selling book is about, and the one thing he has that his competition/peers like Ezra Klein or Matt Yglesias don’t. And one of Nate Silver’s very first, very public hires (Roger Pielke Jr.) sucks at statistics. Not “published something in need of minor correction once or twice” sucks. “Doesn’t understand how a t-test works” sucks. “Doesn’t understand basic probability” sucks. Sucks out loud. Sucks on ice.

Roger’s very first article for Silver’s new site is, unsurprisingly, about Roger’s hobbyhorse. The claim that disaster losses are not increasing due to climate change.

Let’s be clear about some things. Climate change is real. Humans are not just “contributing” to it, we are responsible for essentially all of it over the past several decades. Our perturbation of the climate through our emissions of greenhouse gases is fundamentally changing the Earth system. The biosphere and human systems are going to have to adapt to a rate of change as of now unseen anywhere else in the paleoclimatic record. In the absence of emissions stabilization, a difficult but decidedly achievable outcome, the threat to the biosphere and society is daunting. The amount of climate change we’ve already experienced, while extremely serious, is tiny compared to the impacts we will see in world of unchecked fossil fuel exploitation. In addition to changes in the average or mean state of the system, we have already begun to see changes in some types of extreme weather events, and changes to the drivers of yet other extreme events.

Ostensibly, Roger Pielke Jr. accepts all of the above. He just doesn’t want you to focus on this big picture. Instead Pielke wants you to believe and to focus on the claim that we’ve seen no increase in “normalized” damages due to climate change. The fundamental conceit of this claim is that even though disaster losses are unquestionably on the rise, once you account for changes in the value of infrastructure being built in areas affected by disaster (due to population growth, inflation, etc.), there is no “statistically significant increase”.

This claim rests on our ability to account for factors which might spuriously inflate the damages caused by disasters, but also our complete failure to account for factors that have allowed us to avoid even greater losses.

The case of 2012’s Superstorm Sandy is illustrative. While Roger spent the first few days of the disaster trying to play down the magnitude of the mounting carnage, Sandy ultimately ranked among the most costly storms on record, even using normalized losses. Preliminary estimates range from $50-65 billion USD.

And yet it could have been so much worse.

Hurricane Sandy uncharacteristically failed to recurve out to sea, and barreled back towards the East Coast of the US. Due to the amazing advances we’ve seen in our ability to model the global weather system, we knew well in advance that this unexpected turn by Sandy was a real possibility.

This possibility was taken into consideration by those trying to game out the impact of Sandy’s landfall. The impact of rising sea levels on the frequency and severity of storm surge flooding was as well. Looking to a future of warming-boosted surges, researchers identified huge vulnerabilities in the New York transportation infrastructure to previously rare events. Such considerations ultimately led the MTA to shutdown the subway system in order to avoid the corrosive impact of salt water if the tunnels were flooded. This decision, informed by modeling and meteorological sophistication unimaginable in the early 1900s, saved the subway system and prevented New York City from being paralyzed for weeks and nearly doubling the economic damages.

Image via Twitter

Roger Pielke Jr.’s “normalized” disaster loss fixation takes none of this into account. Nor does it account for the benefits of building code improvements. Or other disaster prevention measures like dikes.

Paul Krugman is among a growing list of knowledgeable folks who were hopeful about Silver’s new enterprise but are less than impressed. Krugman writes:

… data are never a substitute for hard thinking. If you think the data are speaking for themselves, what you’re really doing is implicit theorizing, which is a really bad idea (because you can’t test your assumptions if you don’t even know what you’re assuming.)

I feel bad about picking on a young staffer [Note: not Pielke Jr.], but I think this piece on corporate cash hoards — which is the site’s inaugural economic analysis — is a good example. The post tells us that the much-cited $2 trillion corporate cash hoard has been revised down by half a trillion dollars…

… what does this downward revision tell us? We’re told that the “whole narrative” is gone; which narrative? Is the notion that profits are high, but investment remains low, no longer borne out by the data? (I’m pretty sure it’s still true.) What is the model that has been refuted?

“Neener neener, people have been citing a number that was wrong” is just not helpful. Tell me something meaningful! Tell me why the data matter!

Though Krugman is referring to a different 538 article, he could easily be making the same criticism of Pielke’s. Why do Pielke’s data matter? Are disaster losses not increasing? They are. Does “normalizing” the loss data tell the whole, unbiased, story? No, it doesn’t. Are extreme events, and drivers of yet more extreme events, changing in response to GHG emissions? They are.

If Nate Silver’s mission is to bring statistical cachet to good journalism, he’s off to a terrible start. One of his first big hires is terrible at statistics. If Silver wants to tell us something meaningful instead of peddling freakonomics-lite contrarianism, he’s similarly off to a poor start. Pielke’s personal hobbyhorse obscures far more than it enlightens. It offers a cocktail party morsel of contra-conventional wisdom instead of intellectual nourishment.

There are probably a lot of people who would like to see Silver fail. I’m not one of them. I just won’t be one of his readers, either, unless he makes some big changes to his current model.

Roger Pielke Jr. just can’t help himself

At Keith Kloor’s a little while back, I tried to reach something of an amicable cease-fire with Roger Pielke, Jr. I decided to set aside his constant attacks on the scientists who blog at RealClimate in the interest of moving the discussion on mitigation options forward.

Roger, though, just can’t help himself.

Stefan Rahmstorf and Dim Coumou published an article in PNAS examining the influence of warming on the likelihood of extreme temp events, notably in the context of the blistering 2010 Russian heat wave. Roger accuses Rahmstorf of cherry-picking his period of analysis, and then uses this accusation to cast aspersions on the integrity of climate science more generally.

Here is another good example why I have come to view parts of the climate science research enterprise with a considerable degree of distrust.

Climate science — or at least some parts of it — seems to have devolved into an effort to generate media coverage and talking points for blogs, at the expense of actually adding to our scientific knowledge of the climate system. The new PNAS paper sure looks like a cherry pick to me.

What’s Roger’s actual complaint with the Rahmstorf and Coumou paper? Roger writes:

Look at the annotated figure above, which originally comes from an EGU poster by Dole et al. (programme here in PDF). It shows surface temperature anomalies in Russia dating back to 1880. I added in the green line which shows the date from which Rahmsdorf and Coumou decided to begin their analysis — 1911, immediately after an extended warm period and at the start of an extended cool period.

Obviously, any examination of statistics will depend upon the data that is included and not included. Why did Rahmsdorf and Coumou start with 1911? A century, 100 years, is a nice round number, but it does not have any privileged scientific meaning. Why did they not report the sensitivity of their results to choice of start date? There may indeed be very good scientific reasons why starting the analysis in 1911 makes the most sense and for the paper to not report the sensitivity of results to the start date. But the authors did not share that information with their readers. Hence, the decision looks arbitrary and to have influenced the results.

Roger obviously didn’t bother to actually read the paper he’s attacking.

If there’s one thing Roger can’t stand, it’s scientists pointing out that man-made global warming is making certain kinds of extreme events worse. If there’s another thing he can’t stand, it’s the scientists who blog at RealClimate. Put them together, and Roger goes off the deep end.

UPDATE:

Caught out, Roger is predictably moving the goal posts rather than acknowledging that his attacks were unjustified.

First Roger attacked Rahmstorf and Coumou for ignoring the pre-1911 data. He uses this ostensible sin of omission to smear the larger field. Except of course this is completely false. When this is pointed out, Roger moves the goalposts and claims that Rahmstorf and Coumou didn’t actually look at the 1880-2009 data because they didn’t use a linear trend to look at the 1880-2009 data. [Edited to add: this is an implicit rather than explicit claim by Roger, as we’ll see.] The paper is quite clear about making the case that the data (for 1911 on and for 1880-2009, for synthetic data and actual obs) are better described by a nonlinear trend, and the passage I cited in the original point makes it clear that the 1880-2009 data were analyzed using a nonlinear trend.

Roger then has the chutzpah to claim that Rahmstorf has “confirmed” Roger’s “critique”:

It would be quite shocking indeed if Rahmstorf actually “confirmed” Roger’s critique. But of course he did no such thing. When Roger claims “they did not run the analysis from 1880”, he’s completely wrong (see the above excerpt from the paper). When he claims Rahmstorf has “confirmed” his critique, what Roger really means is that Rahmstorf confirmed that they did not look at the 1880-2009 data using a linear trend– which, again is perfectly clear in the paper itself. So it has gone a bit like this:

Roger: “They didn’t look at the whole record!”

Uh, yes, they did.

Roger: “No, they didn’t perform The Analysis* for the whole record!”

*Valid only for Roger’s definition of “The Analysis”.

Roger has taken a concession that the paper did not do something it never claimed to have done and declared victory. Perhaps at some point he’ll realize that claiming something does not make it so.

FURTHER UPDATE:

Roger has repeatedly made the claim that Stefan Rahmstorf “confirmed” Roger’s critique. Roger’s original critique was that the 1880-1910 were not analyzed by Rahmstorf and Coumou. This original critique is patently false, as the paper shows in the excerpt I posted above.

The basis for Roger claiming that Rahmstorf “confirmed” his critique was Rahmstorf stating that a linear trend was not used in analyzing the 1880-2009, as is clear in the paper.

I let Rahmstorf know that Roger was claiming Rahmstorf confirmed Roger’s critique. Rahmstorf responded:

That is truly bizarre, since what I responded to Pielke (in full) was: “We did not try this for a linear trend 1880-2009. The data are not well described by a linear trend over this period.” As shown in the paper and above, our main conclusion regarding Moscow (the 80% probability) rests on our Monte Carlo simulations using a non-linear trend line, and of course is based on the full data period 1880-2009. Nowhere did we “use 1910-2009 trends as the basis for calculating 1880-2009 exceedence probabilities”, and I can’t think why doing this would make sense. Faced with this kind of libelous distortion I will not answer any further questions from Pielke now or in future. As an aside, our paper was reviewed not only by two climate experts but in addition by two statistics experts coming from other fields. If someone thinks that using a linear trend would have been preferable, that is fine with me – they should do it and publish the result in a journal. I doubt, though, whether after subtracting a linear trend the residual would fulfill the condition of being uncorrelated white noise, an important condition in this analysis.

And on a final note, Pielke actually had the nerve to write this:

You may read the paper differently than I do and you may interpret Rahmstorf’s comments differently than I do — happens all the time on these blogs. In such a situation I propose that the best course of action would be to solicit further information to resolve the dispute. Or, perhaps you’d rather we just make comments about motives and call each other names

This, after he wrote a post impugning the field over an “omission” that existed only in his mind. Unreal.