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Category: Statistics

The general theory, methods, and philosophy of the Science of Guessing What Is.

March 7, 2008 | No comments

Afternoon at GISS

Tim Hall at the Goddard Institute for Space Studies invited me to give a seminar on statistical hurricane modeling. A link to my presentation is below.

Tim, with Stephen Jewson, is doing some interesting work on modeling hurricane tracks, so far mainly in the Atlantic. He has some papers on the GISS web site which you can download. He’s using this work to better quantify landfall frequencies, which are of obvious interest.

What I found most intriguing is that he’s able to show how the location of tropical storm cyclogenesis shifts towards Africa as sea surface temperature increases. Storms born here can tend to be stronger, but they are also less likely to make landfall in the US because of the greater distance.

I got some good comments on my model. Some people did not like that I used the AMO and instead asked for direct SST measures. Well, some like the AMO and some don’t. But I’m perfectly happy to try SSTs. At the least, it’ll make my model a better forecast model.

Didn’t get to meet Hansen, as he’s obviously too busy most of the time. Tim told me that he receives so many requests to come and give talks, that some of the other staff sometimes takes his place.

Here is my talk, in PDF format. Not too many words on the slides, I’m afraid, as I really hate words on slides. Nothing worse than having somebody read words on a slide that everybody in the room can already see. But you can go to my resume page and download the paper to get some words.

March 5, 2008 | 7 Comments

Titan TV’s short piece on the Heartland Conference

A couple of days ago I wrote that people from Titan TV interviewed me, and a slew of others, at the Heartland Climate Conference. Their piece is now on the web and can be found here. I didn’t make the cut, sadly; proving once again I have the perfect face for radio.

I gather, by the selection and arrangement of the sounds bites presented, the Titan TV reporter was attempting irony and humor, which I can tell you ain’t easy. Most who try fail.

Oh—and you’ll get this if you watch the two-minute video—I do not own a car, or motorcycle, or any other form of transportation, not even a bike, and I have not owned any of these for over a decade. I walk most places and I actually do use those miniature fluorescent light bulbs to illuminate my exorbitantly expensive 800 square feet, but only to foil Con Edison’s plan to take as much of my paycheck as the money-besotted Congress does.


Heartland Climate Conference Summary

This is an editorial that I sent out to various places.

I am one of the scientists that attended the recent Heartland Climate Conference in Manhattan, where I live. It is my belief that the strident and frequent claims of catastrophes caused by man-made global warming are stated with a degree of confidence not warranted by the data.

Although it is a logically fallacy to invoke this argument against opponents, let me say first that I have never accepted any money (except my graduate student tuition) for the work I have done in statistical meteorology and climatology. Incidentally, it isn’t because I wouldn’t, it’s just that nobody’s ever offered. I also did not get the one-thousand dollar honorarium from Heartland for speaking at this conference.

At the conference, I presented the same original research that I recently gave at the American Meteorological Society conference in New Orleans. I serve on the Probability and Statistics Committee of the AMS. This work was based on a paper I wrote and is about to appear in the Journal of Climate that shows that the number of tropical storms and hurricanes have not increased in number or intensity since we have had reliable satellite measurements. I also find that previous crude statistical methods others have used to analyze hurricanes have given misleading results.

It is trivially true that man, and every other organism, influences his environment, and hence his climate. It is only a question of how much, is it harmful, and can the harm be mitigated. It is indisputable that mankind causes climate change, even harmful change. But most of this change is local and due mainly to land use modifications. For example, replacing a forest with crop land creates different heat exchange characteristics in the boundary layer. These differences are easily measurable: cooler nighttime temperatures over crop land is an easy example.

It is important to recognize that some changes to our climate are beneficial. That converted crop land, for example, feeds people, which most would agree is a benefit. Diverted and dammed rivers provide water.

We also know with something near certainty that carbon dioxide has been increasing since the late 1950s. We are less certain, though nearly sure, that it has been increasing since about 1900. Before this date, we are even less certain of the global average amount. The reason is that before 1959 there were no consistent direct atmospheric measurements and so we must estimate the values based on proxies. Converting proxies to estimates requires statistical modeling. Part of every statistical model is, or should be, a quantification of the uncertainty of the estimates. This uncertainty is known by those who convert the proxies, but nearly always forgotten by those who use the estimates as input to climate or economic models.

It is absolutely clear that mankind is responsible for a portion of the carbon dioxide increase. What most people—not climatologists, but others—do not know is that this portion is only a fraction of the increase. The rest of the increase is due to other causes. These causes are not fully understood—a sentence you have often seen, and which means that we are not certain.

Temperatures have been directly measured for a little over a century. The number of locations at which temperature is taken has gradually increased, reaching something like full coverage only in the last thirty to forty years. It is certain that at many individual stations mankind has caused changes in measured temperature. Mankind caused both warming, due to the urban heat island effects, and cooling, such as by land use changes.

Joining these disparate measurements, and controlling for the changes and increases in locations, and the changes known to be due to urban heat island and other land use changes, to form an estimate of global average temperature again requires statistical modeling. And very difficult and uncertain statistical modeling at that. The resulting estimate should be presented with its error bounds, though it never is. These error bounds are currently larger than any projected increases in temperature, which makes it difficult or impossible to verify climate model output.

Surprisingly, climate models are not certain. We have deduced, and therefore know, the fundamental equations of motion, but there is some uncertainty in how to solve them inside a computer. We also are fairly sure of the physics of heat and radiative transfer, but there is large uncertainty in how to best represent these physics in computer code because climate models describe processes at very large scales and heat physics take place at the microscopic level. So these physics are parameterized, which increases the uncertainty in the climate model forecast.

All climate models undergo a “tuning” process, whereby the parameterizations and other parts of the computer code are tweaked so that the model better fits the past observed data. This necessary step always increases the uncertainty we have in predicting independent data, which is data that has not been used in any way to fit or tune the models. And it is a fact, and therefore certain, that, so far, climate models have over-forecast independent data, meaning that they have said temperatures would be higher than have actually occurred.

Lastly, there is the abundance of secondary research that uses climate model output as fixed input. This is the work that shows global warming causes every possible ill. I have never met one of these studies that quantified the uncertainty due to assuming climate models are error free. This means that their conclusions are vastly overstated.

Too many people are too confident about too many things. That was the simple message of the Heartland conference, and one that I hope sinks in.

Update 6 March: I have been getting some private questions, so I wanted to emphasize that I have not even gotten grant money to do my meteorology/climatology work. Any grant money I did get was from my advisor for my research fellowship in mathematical statistics when I was a graduate student. Since then it has been in the form of NIH and private foundation grants for biostatistical work. Unlike most climate researchers, I do it for fun and not for profit.

March 4, 2008 | 19 Comments

Heartland conference: day 3 and wrap up

Czech Republic President Vaclav Klaus started off the day with a rousing speech. I hadn’t known he was an economist, but it was obvious quickly through his use of phrases like “maximize their personal utility function” and “is there statistically significant global warming?” This was not a standard political speech.

He joked that certain people “want to stop economic growth [in Europe]; though, not their own,” particularly in developing countries. Klaus was most authoritative by reminding us of living under communist rule which featured “central planning of all kinds of human activity.” Communists, and the socialists like them, “believe in their ability to assemble all relevant data” and to give instructions to millions of people. He talked of how some enlightened folks want a return to this type of control because, of course, they are experts and know what’s best for everybody. Sound like academia to anybody else?

I believe his speech will eventually be made available on the Heartland website.

Bill Gray went next, but started off with what I felt was an unfortunate comment. He said that model climate modelers “don’t have much background on how the atmosphere ticks.” The statement is strictly false, and even ridiculous. It was offered in a friendlier spirit than it reads: more of a “weather weenies” (yes, this is what we call them) versus “climate modelers”. The former are the day-to-day weather forecasters, the guys who memorize the pressure, vorticity and CAPE of each storm back to 1965. The later are the guys who sweat over partial differential equations and, obviously, write computer code. There is always a tension between the two groups, but a good natured one.

But some people won’t understand the “inter-service rivalry” undertone. All they’ll hear is that Bill Gray said climate modelers don’t know how the atmosphere “ticks”, which will cause them to then trot out the qualifications of some climate modelers saying, “Look here. This guy has a PhD and 82 papers and can integrate you under the table.” And they’d be right.

It’s understandable for some people to want to score some points against the more outrageous claims of the “other side”, but I think it’s best done through plain writing or through humor. Public petulance and overstatement just will not work except against you.

If you’ve ever been to a science conference you’ll know that much of the best stuff happens out in the halls, which is where I spent the rest of my morning chatting with Jennifer Marohasy, Craig Loehle, Willie Soon, David Legates, Joel Schwartz and others. We talked mostly of work and upcoming papers and went through the standard ritual of griping about journal editors and the ridiculous hoops we sometimes have to jump through to get papers published. But some of the guys had absolute horror stories of what happened to them when they tried getting papers published that explored non-“consensus” views. Really outrageous and unethical behavior on the parts of some editors. I was shocked. I’d like to be able to tell some of these stories, but they belong to their owners, and I’ll let them do it.

Lord Monckton joined our group and said that he was off to, inter alia, the University of Rochester to talk about his climate sensitivity work. He’ll be writing it up soon and working with some scientists there to better quantify some of the ideas. I look forward to this because it is an excellent opportunity to not only get better point estimate of the quantities involved, but to also quantify their uncertainty. Specify error bounds, if you like, which is something that is almost never done!

Monckton also spoke on Glen Beck‘s radio show this morning and had some words to say about Jim Hansen who, as a government official, “condemned” two of Lord Monckton’s speeches. The transcript of the Beck interview is here. Here’s a blurb

So I wrote to the administrator of NASA and I said, [Hansen’s] conduct is not acceptable; I want it investigated and I think there are financial irregularities behind the conduct of your people in this matter and given that they have financial links with Al Gore. And so they are, in fact, now investigating it. It was referred to the inspector general of NASA who is their internal affairs officer, and he is now looking at this. And if they don’t come back to me very soon and say that they have disciplined this man for making unscientific statements when he’s a paid public official against a private citizen — that’s what he did — then I am going to refer this case via diplomatic channels to the U.S. attorney general’s office because they are the only office who are allowed to refer investigations to the Securities & Exchange Commission.

Oh. I also asked if his “stellar solar scientist” remark from yesterday was a planned pun. He said, with body language indicating the opposite of his words, “Well, of course it was.”

I had to get back by noon and so missed the wrap up talks, including one by John Stossel which I would have liked to have heard.

Though there was the “Manhattan Declaration on Climate Change”, which can be found here. This was circulated late this morning and people were asked to sign in public or anonymous support. Go and read it and see what you think.

The natural question is: Was the conference a success? To answer that requires time and waiting. For me it was successful because I got to meet some colleagues that I had only previously corresponded with. I got some work to do out of it, too. Plus, I was able to learn about some of the political aspects of the debate, though I am still abysmally ignorant here.