American Elephants


Determining risk by using computer models is more complicated than you might think. by The Elephant's Child

Last Friday the U.S. National Snow and Ice Data Center admitted that their sea ice data was off by as much as a half-million square kilometers due to “sensor drift” of the old satellites that they were using.

A new satellite is available, and it is far more precise, but the Snow and Ice Data Center does not use it because its data is inconsistent with their historical data.  The idea of an “ice-free pole” is so much the consensus that they do not want ordinary facts to get in their way.

The extent of Arctic sea ice is an important measure of how rising or cooling temperatures are affecting Earth’s climate.  The satellite sensors caused scientists to underestimate the extent of sea ice by 50,000 kilometers (193,000 square miles) or about the size of California.  But this small error does not change their findings that Arctic ice is retreating.

An article from Anthony Watts blog by Machine Design editor Leland Teschler points out that financial institutions have employed legions of PhD mathematicians and statisticians to model the risks that the firms were assuming under a variety of scenarios.

Huybert Groenendaal’s PhD is in modeling the spread of diseases.  He points out that:

In risk modeling you use a lot of statistics because you want to learn from the past.  That is good if the past is like the future, but in that sense you couuld be getting a false sense of security.

That sense of security plays directly into what happened with banks and financial instruments based on mortgages.  It gets back to the use of historical data.  One critical assumption people had to make was that the past could predict the future.  I believe in the case of mortgage products, there was too much faith in the idea that past trends would hold.

In our experience people have excessive confidence in their historical data.  That problem isn’t unique to the financial area.  You must be cynical and open to the idea that this time, the world would change.  When we work with people on models, we warn them that models are just tools.  You have to think about the assumptions you make.  Models can help you make better decisions, but you must remain skeptical.

Climate change is similar to financial markets in that you can’t run experiments with it as you might when you are formulating theories in physics.  That means your skepticism should go up.

Lots to ponder here.  Read the whole thing.


7 Comments so far
Leave a comment

American Elephants said, “A new satellite is available, and it is far more precise, but the Snow and Ice Data Center does not use it because its data is inconsistent with their historical data.”

I thought the NSIDC had switched their sensor after discovering and taking down the month and a half of inaccurate readings.

Here’s the info from their web site: http://nsidc.org/arcticseaicenews/index.html

February 26, 2009
Near-real-time data now available

Near-real-time sea ice data updates are again available from Arctic Sea Ice News & Analysis. We have switched to the Special Sensor Microwave/Imager (SSM/I) sensor on the Defense Meteorological “Satellite Program (DMSP) F13 satellite following the sensor drift problem described in our February 18 post.

The temporary error in the near-real-time data does not change the conclusion that Arctic sea ice extent has been declining for the past three decades. This conclusion is based on peer reviewed analysis of quality-controlled data products, not near-real-time data.”

Cassandra

Like

Comment by uncommonscolds

Yes, I know they fixed the problem. I was not as clear as I should have been. The other problem is captured by your last paragraph. They are not going to let their observed data get in the way of “consensus” by “peer reviewed” “quality controlled” data. Which doesn’t mean diddly-squat.”Peer-reviewed” doesn’t mean that it is necessarily true. “Consensus” isn’t science, and “quality-controlled” doesn’t necessarily mean anything. What quality and what standards? My objection is to allowing computer programs to trump observed science. If you have noticed, the Fed’s computer financial programs have caused some major problems for the economy.

Like

Comment by The Elephant's Child

Thanks for the quick response. You have some good points, and, as usual, I now have more questions.

The Elephant’s Child said, “They are not going to let their observed data get in the way of ‘consensus’ by ‘peer reviewed’ ‘quality controlled’ data.”

I’m not sure what you mean here. First, who are “they”? Do you mean the NSIDC people? Do you mean “they” have agendas and are manufacturing data? If so, wouldn’t this be a major and identifiable breach of scientific method?

I totally agree that “‘[p]eer-reviewed’ doesn’t mean that it is necessarily true.” In fact, peer-reviewers often disagree heartily with articles they approve for publication. As you also undoubtedly know, the process is just intended to catch obvious errors or lapses in applications of methodology and such. Science advances through the vocal, combative scraps that follow publication or presentation of peer-reviewed material. Something resembling consensus arises when the data from many studies leads to a pattern of patterns that eventually convinces most.

For example, that’s why the the critiques of the original hockey stick theory were so useful in correcting and refining its errors. To me, that’s how science works. Scientists rarely hit 100%, but the best of them get it a bit righter each time their peers point to problems.

The Elephant’s Child said, “My objection is to allowing computer programs to trump observed science.”

I agreed 100%!

This is why I found the last part of the NSIDC article from February 26 so relevant. Didn’t the scientists do exactly what you want? Didn’t they go with “observed science” rather than the faulty computer data?

That’s the way I read this NSIDC statement: “The temporary error in the near-real-time data does not change the conclusion that Arctic sea ice extent has been declining for the past three decades. This conclusion is based on peer reviewed analysis of quality-controlled data products, not near-real-time data.” [emphasis added]

And don’t get me going on the Fed.

Again, thanks for the response.

Cassandra

Like

Comment by uncommonscolds

The earth has been cooling for a decade. The increase in sea ice has been the fastest change either up or down since 1979 when satellite record keeping began.

Dr Mark Serreze of the NSIDC claimed in April of 2008 that there would be an ice free pole in 2008. Never happened. He also claimed “Arctic ice is in its death spiral”and the “entire north polar ice cap will be gone within 5 years.” See meteorologist Anthony Watts’ wattsupwiththat.com excellent website.

Global sea ice according to U. of Illinois’ Arctic Climate Research Center notes that global sea ice levels now equal those of 1979. The fall in global temperatures have essentially wiped out all the warming of the past century.

Michael Mann has not given up on his hockey stick even though it has been completely discredited since any data entered produced the same hockey stick graph. Mann is still trying to come up with a new version.

Like

Comment by The Elephant's Child

Thank you for the explanation, but I need more source material here.

I’ll look up Mark Serreze and the UI Research Center myself, but I’d like to see a list of your sources for the remark on cooling and the hockey stick. I’ve seen multiple sources that dispute the claims of cooling and, from what I’ve read, the revised hockey stick is still quite well accepted. But it’s been a few months since I’ve seen anything on that matter, so I gather you’ve got something new that I’ve missed.

I spend way too much time reading the abstracts of recent academic studies without finding the conclusions you state, so I look forward to enlightenment here. Which journals and/or articles did I miss?

Believe me, I really, REALLY want to see what you’re saying, but I teach research, and I can’t believe anything without seeing the sources behind the conclusions.

Thanks again for the response.

Looking forward to your list!

Cassandra

P.S. Please, don’t list sources from ANY agenda-driven think tanks of ANY persuasion. Primary studies are best. But, like you, I am not a scientist, so I’m often limited to reading the “conclusions” and “discussion” paragraphs and then sending them out to my scientist friends for confirmation that my understanding of what I read was within acceptable boundaries. Of course, I will accept secondary sources if the authors have sufficient academic credentials and no history of being hired-guns for industry or political parties. (And, yes, I know that academics can be hired guns too, but that’s why I like the peer-review process. Hired guns usually have to cherry-pick and that’s what the peer-review process is there to stop.)

Like

Comment by uncommonscolds

I had some free time and checked those two Items I mentioned in my last post. Here’s what I found.

You said, “Dr Mark Serreze of the NSIDC claimed in April of 2008 that there would be an ice free pole in 2008. Never happened.

Again, you are absolutely right if you meant that this CLAIM never happened. I wondered about this statement since every scientist I know qualifies virtually EVERYTHING. And there’s a reason for this–they might be wrong. As I expected, Serreze qualified his statements in every source I could find. Here are a few with emphasis added:

North Pole Could Be Ice Free in 2008
By CATHERINE BRAHIC
April 27, 2008

“There is this thin first-year ice even at the North Pole at the moment,” says Serreze. “This raises the spectrethe possibility that you could become ice free at the North Pole this year.”

Source: http://abcnews.go.com/Technology/Story?id=4728737&page=1

Arctic Ice in “Death Spiral,” Is Near Record Low
Mason Inman
for National Geographic News
September 17, 2008

“The ice is in a ‘death spiral’ and may [MAY–not WILL] disappear in the summers within a couple of decades, according to Mark Serreze, an Arctic climate expert at the National Snow and Ice Data Center in Boulder, Colorado.

Source: http://news.nationalgeographic.com/news/2008/09/080917-sea-ice.html

—By the way, NatGeo’s a high end, popular source. Well worth a read.

North Pole Could Be Ice-free This Summer, Scientists Say
CNN NEws updated 3:34 a.m. EDT, Fri June 27, 2008

(CNN) — The North Pole may be briefly ice-free by September as global warming melts away Arctic sea ice, according to scientists from the National Snow and Ice Data Center in Boulder, Colorado.

“We kind of have an informal betting pool going around in our center and that betting pool is ‘does the North Pole melt out this summer?’ and it may well,” said the center’s senior research scientist, Mark Serreze.

It’s a 50-50 bet that the thin Arctic sea ice, which was frozen in autumn, will completely melt away at the geographic North Pole, Serreze said.

Source: http://www.cnn.com/2008/WORLD/weather/06/27/north.pole.melting/

I also checked out this comment you made: “Global sea ice according to U. of Illinois’ Arctic Climate Research Center notes that global sea ice levels now equal those of 1979.”

You didn’t get this from George Will’s op-eds did you?

George Will’s reliance on popular sources and misinformation is despicable. I used to respect Will and read him with eagerness, even when I disagreed with many of his conclusions. Now I think he may be suffering from the onset of senile dementia. And that’s the kindest thing I can say.

Here’s a link to “The George Will Affair” at the Columbia Journalism Review. I won’t bother repeating the trail of errors that they detail so clearly.

Even the Global Warming Hoax: Where Only the Truth Heats Up notes that Will has been incorrect. Here’s what they said:

Even the University of Illinois’ Arctic Climate Research Center got in to the fray saying this on their website:

We do not know where George Will is getting his information, but our data shows that on February 15, 1979, global sea ice area was 16.79 million sq. km and on February 15, 2009, global sea ice area was 15.45 million sq. km. Therefore, global sea ice levels are 1.34 million sq. km less in February 2009 than in February 1979. This decrease in sea ice area is roughly equal to the area of Texas, California, and Oklahoma combined. [Note: I verified that this info is indeed from http://arctic.atmos.uiuc.edu/cryosphere/%5D

So was George Will wrong? It turns out George Will was quoting a source that later corrected its data, not George’s fault.

Source: http://www.globalwarminghoax.com/comment.php?comment.news.107.1

I sort of blinked when I read this site’s line “Not Will’s fault.” OK. I can go with that, but only so far. People get incorrect data all the time. But responsible researchers and responsible journalists CORRECT their mistakes publicly and quickly. Not retracting and correcting immediately–now THAT’s Will’s fault.

I’m sorry, but I guess I’ll have to keep looking elsewhere for solid info against climate change. So far, no matter where I look, I’m finding only material that flunks basic evaluation standards. I’m finding distortions, misrepresentations, and cherry-picking.

And, alas, too many well meaning people are gobbling all that down without doing the necessary research for themselves.

Sigh. In any event, good luck. I hope you find something solid.

Cassandra

Like

Comment by uncommonscolds

I relied on Anthony Watts’ site, and his satellite photos of Arctic sea ice, and his comments on George Will’s piece. You and I differ on where to get reliable information. I would not consult National Geographic for anything other than pretty pictures, they are complete Global Warming activists. Nor would I consult CNN or global warming hoax, as I regard them as partisan.

The Pole was never free of ice last year according to what I have seen. If you remember, someone was going to kayak to the pole at the most ice-free point and got stuck in the ice and had to be rescued. And there was a boatload of scientists and reporters who were heading for the pole to show the world how much warming there was, and they got stuck in the ice as well and also had to be rescued. I cannot compare square miles of ice from now or then — I haven’t measured, and only observed science matters..

Referring to impeccable resources — the Supreme Court ruled that the government could classify CO2 as a pollutant, perhaps the silliest ruling ever.

The CO2 in the atmosphere arises from the oceans, and increases as much as 100 years after warming, so cannot be causative. Anthropogenic CO2 is such a small part of the so-called greenhouse gasses that it can barely be measured at all. The EU has gone to great lengths to stamp out CO2, and it has not made any measurable difference whatsoever. And all those rules and cap-and-trade policies had no effect except to damage the EU economy.

There are more polar bears than ever, yet they have been classified as a “threatened” species because of the “lack of ice,” though they have lived just fine through far warmer periods and far colder periods in the last 30,000 years.

You are consulting only sources committed to the global warming theory. You need to read more on both sides if you want to be informed. It’s not as easy as just confirming numbers.

Like

Comment by The Elephant's Child




Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s



%d bloggers like this: