Science Cafe Experience

Thursday I had my first experience with a Science Cafe. I chatted with the folks in Annapolis about ice ages. Much fun!

The idea in a science cafe is to bring in a scientist to talk about his work -- a little, not a lecture, just enough to provide fodder for questions and discussion. And then field questions and encourage discussions about that area. My set piece was about 15 minutes, and 45 minutes for discussion after. The audience was excellent since they did start asking questions promptly and they were sincere questions. We met at a cafe, so I also had a chance to eat and have a beer first.

My wife and son enjoyed the event too. Though they've heard me go on about ice ages before, it was just such a good group engaging in the questioning and fitting ideas together.

If you have a chance to talk at one, do! If you have a chance to attend one, do that too. We'll be going, ourselves, whether I'm the main speaker or not.

Unreliability at Icecap.us

[Update 10 August 2008: It turns out that D'Aleo was not willing to leave bad enough alone. You can see my responses at More from Icecap If you haven't already, please do read this post to know what I actually said.]

Since I'm an ice guy, I'm saddened that a place with ice in its name turned out to be unreliable. Still, I wandered over there and took a look at the first article on their main page (as of Aug 3rd, 8 AM) in the 'new and cool' section. The article was http://icecap.us/images/uploads/Examiner_Story.pdf by Joseph D'Aleo (Seems to have been published first on 31 July in the Examiner). In very short order, I found a major error, a cherry pick, and an error or at least misleading graphic. I stopped there.

The first is straightforward error, and the initial red flag is one which needs no special knowledge:

NASA’s JPL reported their 3000 global ARGO diving buoys deployed in 2003 have shown the world’s oceans have too cooled.

The thing is, science is done by scientists, not institutions. If he's reading the science, the author would be giving us scientist names (and institutions, perhaps). The scientists involved are at several institutions, as is typical. And, as adults know, scientists do not speak for their employers.

So let's look at the science on ARGO and ocean heat content, and see what's out there. In short order, I found http://oceans.pmel.noaa.gov/pubs.html , which shows two papers with interesting titles:
2006 Lyman, J. M., J. K. Willis, and G. C. Johnson, 2006. Recent cooling of the upper ocean. Geophysical Research Letters, 33, L18604, doi:10.1029/2006GL027033.

2007 Willis, J. K., J. M. Lyman, G. C. Johnson, and J. Gilson. 2007. Correction to "Recent cooling of the upper ocean". Geophysical Research Letters, 34, L16601, doi:10.1029/2007GL030323.

If you go to the web site and select the link for either paper, you'll get both. The comment by D'Aleo, written in 2008, is in accord with 2006's paper. But it ignores the 2007 correction. Since D'Aleo is a fellow of the AMS, it is not plausible that he couldn't know about the correction a year later, particularly as it appeared in the same source as the original.


Immediately following is an eye-catching graph of temperatures (as observed by the MSU, but he doesn't tell us whose MSU data, and there are significant differences between sources). It also plots carbon dioxide levels. The illustration could have come straight from Darrell Huff's excellent How To Lie With Statistics. We're invited to think that the CO2 curve is an estimate of how much atmospheric temperatures are expected to have risen at the time the temperatures were 'dropping'.

0.6 degrees (are those C or F? again, he doesn't tell us something important) seems like an awful lot to expect from a rise of 12.5 ppm (my eyeball estimate from the curve). How much might we expect? Well, suppose that the temperature increase were 1 C over the last century and all of it was due to CO2 (which we don't expect in the science; there are other things going on too). CO2 is up about 100 ppm in that time. Our simplest plausible figure then is that we expect about (12.5/100)*1 degrees warming, or 0.125. The slope of that CO2 curve is about 5 times too large! View the graph again, but for the CO2 line, put your pencil so that it runs from the 0.2 degree tick mark to the 380 ppm tick. That's about the warming we'd expect if you made a lot of assumptions in favor of making this comparison in the first place.

With this carefully selected span the trend line on CO2 and temperature seem to go in different directions. But, now that we've put the two on more comparable footing, we see that the temperature record is highly variable, with 0.6 degrees in 6 months happening at least a couple of times. While you can always draw a straight line through data points, you have to ask whether your line is statistically significant. More to the point here, he should have asked whether that noisy temperature line was significantly different from the smooth CO2 line.

Even better, and more honest, would be to ask just what we expect climate to do in 6 years with only 3.5% increase in CO2. The answer is, hard to say. Solar variability is part of the answer, and the sun has been quiet. That means a contribution to cooling. We also expect that weather happens, and the figure shows this to be continuing in the year to year changes. That is part of why we want long series to consider climate with. 6 years is not long.

A little more subtle, but not specialized, is that we don't expect all the energy that would be captured by CO2 to show up as warming in the atmosphere. Though it's the easiest part of the climate system to measure, the atmosphere is not the only part energy can go to. Energy can go in to heating the ocean, land, and melting ice, for example. We've all hear in the last few years of record melts in the sea ice and ice sheets.

So our unreliable source is:
http://icecap.us/ Joseph D'Aleo

Uncritically or enthusiastically endorsed by:

http://www.freerepublic.com/focus/f-news/2055607/posts
http://www.silobreaker.com/DocumentReader.aspx?Item=5_886993410
http://co2sceptics.com/news.php?id=1634
http://tomnelson.blogspot.com/2008/08/climate-change-isnt-happening-tenerife.html

Scientists and the Far Side

In his 10 year retrospective, Gary Larson mentioned that he was surprised that he had a following among scientists. Speaking as a scientist who 'got' all his cartoons, including the ones he said were often misunderstood or not understood at all*, I'm not surprised. For all that there were the talking cows, chickens, etc., and aliens and other unlikely sorts of things, there was a very important scientific theme to the cartoon (actually including those things).

That is, the universe is a strange and interesting place. One of the reasons that we get in to science is because of that. With all the glory and mystery to the universe, what a wonderful thing it is to be a scientist and get paid to try to understand some of it!

*You might want to keep that in mind if I seem a little strange. I probably am. :-)
Then again, see the difference (mentioned in that volume) between Jane Goodall's response to a cartoon and her office person's. Another datum for scientists having better senses of humor than usually portrayed.

Earth temperature 1

The earth's temperature is something I'll probably come back to a few times as it is a lot more involved than you might think. So this is the first part -- the temperature as observed from space.

'Observed from space' shows our first complexity. Satellites can't drop a thermometer into the earth's atmosphere, oceans, etc., to find out what the temperature is. So what can they measure from up there? Fundamentally, they can measure voltages, resistances, currents, counts of an oscillator -- electrical/electronic things like that. Not very helpful at the start. But we can arrange it so that the things we can measure have something to do with what we want to know about.

This is actually how some thermometers work. Think of a traditional old mercury thermometer. It doesn't measure 'temperature', whatever that may be; it measures the length of a thread of mercury. Alcohol thermometers use alcohol instead, but in the same idea. 'Temperature' is the property, then, which makes materials expand (when hotter) or contract (when colder). It was discovered first as a practical matter that materials do expand with temperature in a sense in agreement with our own physical ideas of hot and cold (ex. Mr. Fahrenheit and M. Celsius). So temperature could be equated to expansion of materials. In the 1800s, a firm theoretical basis for which it should be like that (and sometimes not like that at all) was laid down.

For the satellites, a similar process of trying to match up what could be measured to what was desired was involved. The little 'aim it in your ear' thermometers are a little like the satellite method. What they do (satellites more thoroughly, home ear thermometers only in a small color zone) is arrange a detector so that it gets hotter as more radiation falls on it, then measure the resistance/voltage/... of this hotter detector wall.

The satellite detector I've described relies on the Stefan-Boltzmann law to decide temperature -- it measures the energy (which causes the detector to heat up) coming from the earth, and then with the law (Energy = s * T^4, s = the Stefan-Boltzmann constant, wonder why), converts that measured energy to a temperature. That temperature is the 'Black Body' temperature of the earth. If the earth were an ideal black body, the observed amount of energy is what would be seen if the earth were radiating at the given temperature.

We can also make detectors which measure the amount of energy that's within a certain small wavelength interval (blue, for instance). This is how the ear thermometer works, except it uses infrared. Given that observation, and Planck's law (more involved than Stefan-Boltzmann, look it up), we can compute the temperature your inner ear would have to be to be radiating that much energy -- if your inner ear were a black body. It's a fair approximation to one.

In either case, we have a 'Brightness Temperature' -- the temperature the thing you're looking at would have to be to give the observed brightness (energy). In the case of the earth, it is about 255 K, -18 C, 0 F. For Venus it's about 232 K, a good deal colder than the earth. Seriously, check http://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html
to verify, or find some others.

What happened? Venus is supposed to be hot! The earth is seldom as cold as -18 C or 0 F anywhere, much less for a planetary average. Well, Venus is hot (over 400 C at the surface) and the earth's surface is rather warmer (about 33 C or 60 F) than the brightness temperature (black-body equivalent temperature -- same thing).

The thing is, we have to pay attention to what the satellites observe -- radiation. If that radiation comes from the surface, we see a surface temperature. But in general, the radiation comes from somewhere up in the atmosphere. For Venus, it is a very long way from the surface, so very much colder. For the earth it is typically several km (or miles) up from the surface.

If you think this is indirect and complicated, wait 'til we talk about trying to observe the temperature of layers within the atmosphere from space!

Peer review

"It's peer review, not God review." was my wife's response when I asked her whether she thought peer review meant that a paper was 100% correct in all details. She's right, of course. Humans are fallible, and scientists are human. It seems to surprise nonscientists that we've noticed both of those things. In fact, this is part of why peer-review was invented. Scientists do try to do good, careful, accurate work that is without error. But we know that we probably never accomplish this in our own original writing. Having peer reviewers gives a chance for errors of omission and commission to be caught before you take the paper public (rather, before the journal takes the paper public). Or just plain have some other folks, not as intimately involved in your work as you, look over your explanations for clarity and completeness.

Even after peer review, misteaks can remain. Fallible humans can miss errors even when they're just the reviewers. Again, we know this, too. That's why the significance of peer review is not that it is a stamp of perfection, but a stamp of 'there's a pretty fair chance that this work is worth your time to look at'. Conversely, things which aren't peer reviewed are not even peer reviewed. It doesn't mean that the paper is necessarily bad -- a usenet faq of mine (not formally peer reviewed!) has been cited in the peer reviewed literature (Noerdlinger and Brower) as being the first discoverable time that someone computed how much sea level rise there can be from melting the ice packs. (It isn't zero, see the faq for why and how much. See Noerdlinger and Brower for the more complete considerations and experimental demonstration.) But, given that humans are fallible, and time and reading speed is limited, a mark that there's a better chance than usual that the paper at hand is not obviously (to the reviewers) false is a very helpful thing.

The real test, though, is not whether a paper was peer reviewed. Many papers survive peer review that are never cited by anyone other than perhaps the author. These are dead ends. Since I heard that, I check periodically to see whether my papers get cited. They all have been, and not just by me or someone I was working with at the time. Good to know. The really good papers are the ones which get used often to do new science. Science hangs together, in that if I did my work right, someone else can use it to study, say, polar bears, eider ducks, or something -- things which I had no idea of when I did my work. (I'm not a biological science type, though I find it interesting to hear about.)

The polar bear guy used my work because in the areas he could test it (tracking dead polar bears with transmitters), my work on sea ice drift matched well. He then had confidence that in the areas he couldn't test, the work was probably also worth paying attention to. This is where the good science has happened -- somebody else, for some other reason, can see your work pass an independent test and use it.