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!
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31 July 2008
30 July 2008
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.
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.
29 July 2008
Keep your vehicles how you choose
One of the most common responses I get when people learn that I'm a climate scientist is that they tell me we're (climate scientists) all just trying to take away their SUV. Don't know why it's always an SUV when it gets mentioned, but it is. Anyhow, we're not (I don't think so; certainly nobody ever mentioned that policy to me), and I certainly am not. What I'm after is for decisions to be made using good information. Intelligent people of good intent can look at the same information and come to different conclusions. That's life. But a lot of what is out there is bad information. Bad information does not make for good decisions.
For instance, suppose you decided that emitting carbon dioxide was indeed a bad thing to do with the climate system and you have an SUV that gets 20 mpg. Should you toss it for a car that gets 30? I dunno. If you're driving six people in that SUV all the time, and would have to take two cars to carry them instead, you're better off with the SUV. A catch, of course, being that comment about 'all the time'. If very few of your miles are driven with the SUV fully loaded, then two 30 mpg cars would be better. And if the cars were 50 mpg, then even if the SUV really were fully loaded all the time, you would indeed emit less carbon dioxide even with two cars.
One thing I'll add: The people who tell you that climate scientists want to take away your SUV are trying to scare you. They don't want you to think about the science. Even if I'm rather optimistic about some things, I have to figure that people who don't want me to decide based on our best understanding of science are trying to get me to do something I wouldn't if I thought about it.
For instance, suppose you decided that emitting carbon dioxide was indeed a bad thing to do with the climate system and you have an SUV that gets 20 mpg. Should you toss it for a car that gets 30? I dunno. If you're driving six people in that SUV all the time, and would have to take two cars to carry them instead, you're better off with the SUV. A catch, of course, being that comment about 'all the time'. If very few of your miles are driven with the SUV fully loaded, then two 30 mpg cars would be better. And if the cars were 50 mpg, then even if the SUV really were fully loaded all the time, you would indeed emit less carbon dioxide even with two cars.
One thing I'll add: The people who tell you that climate scientists want to take away your SUV are trying to scare you. They don't want you to think about the science. Even if I'm rather optimistic about some things, I have to figure that people who don't want me to decide based on our best understanding of science are trying to get me to do something I wouldn't if I thought about it.
28 July 2008
The Youthful and Damp Dr. Grumbine
A couple of funnies from the last couple days. Yesterday, I was carded in a restaurant when I ordered a beer. Not only am I over 21, but my first paper is as well. :-) Then today I went out to try rowing (scull, not a regular rowboat). Well, the instructor, Cindy Cole http://www.washingtonrowingschool.com/ was good. My wife had been taking lessons for most of the last year (they take the winter off) and, while unsatisfied with how well she was doing (not a teacher issue) was happy about the fact that she had never fallen in to the water. So today I went out to try it, and first time out fell in. This is a rare thing, I'll note. Takes a special level of skill to manage it as only 2 other people have managed it while Cindy's been running the school. I blame the egrets, of which there are many. If you're in the area and have ever wondered about rowing, do come in. I'll be back out Saturday morning, so beware.
Petitioning on climate, part 2
Part 2 here requires a little specialized knowledge, namely that there is a broadly based scientific professional society relevant to climate issues in the US; it is the AGU http://www.agu.org, and they have a class of members who have been recognized for their consistently high quality work (Fellows). The American Meteorological Society, http://www.ametsoc.org, is relevant of course, but is primarily meteorological with only a modest number of oceanographers, glaciologists, hydrologists, ... particularly as compared to the numbers the AGU has. On the other hand, AGU includes space physicists, mineralogists, ... as well, which takes us afield from climate. I'm a member of both societies, so you could call it specialized knowledge to know about them. But these organizations are easy enough to find if you set out looking.
In part 1, we looked a bit at whether the numbers of signers was large. The petition project itself, and even more those who quote it, wants us to believe that there is 'a lot' of scientific opposition. But it turns out that most of the signers are nonscientists, much less scientists in something relevant to climate; worse, the numbers are actually quite small compared to the sizes of the fields they were mass mailing to. Junk mail rate.
For part 2 here, let's look to see whether many of the people in the AGU have signed. We'd want to do a later check whether it was mineralogists vs. atmospheric scientists, but it's a start. Since the AGU has about 50,000 members, I didn't want to try checking the whole list. But AGU fellows are a limited population. Unfortunately, it turns out that the 0.1% I mentioned was how many can be inducted per year. Ouch. There are quite a few more Fellows than I was thinking. Nevertheless, I started checking alphabetically.
Last names beginning with A: 0 of 41 fellows have signed
Last names beginning with B: 0 of 91 fellows have signed
As this is tedious and error prone (just how many 'Browns' are there? yikes. Names like Grumbine are much easier!) I turned to the list of 2008 fellows (not yet included in the full list). There are 51 new members. Checking the names there, I found 2 name matches, but ... Well, the names that matched are Charles R. Bacon and James W. Kirchner. But the Fellow Bacon is working in California and the signer Bacon is in Michigan, while the Fellow Kirchner has a PhD and the signer does not. So we're to 0 of the 51 new Fellows. (I'll note that it isn't a requirement that a Fellow, or AGU member, have a PhD. What matters is doing good work in the area (Fellow) or be studying or have studied the area (member).)
0 of the 183 AGU Fellows I've checked so far have signed the petition. If you'd like to assist the check, please do; send your results to me at plutarchspam at aim dt com. AGU's listing of fellows is at http://www.agu.org/inside/fellows.html The Petition Project's listing of signers is at http://petitionproject.org/gwdatabase/Signers_By_Last_Name.php And, by all means, do recheck my tallies for what I've checked so far.
The real point, though, is that the petition project has tried to mislead us, not the exact numbers. They want us to believe that engineers, doctors, and veterinarians (among other things) are scientists; they're not. They want us to believe that the number of signers is not 'a few', but as I've shown in parts 1 and 2, using only information that requires no special study, it in fact is only a few -- under 1% of the people they consider eligible have signed (in the areas I've checked, to be sure, but I did hit the largest groups). They want us to believe that the petition is about science, but the petition itself doesn't ask any scientific questions (check it out, pay attention to that major weasel word 'catastrophic'), and its main conclusion is actually about signing political agreements -- not science. And ... well, quite a few things, including that being dead is no bar to being on the list. Edward Teller, signer of their sample form, has been dead since 2003.
What should a citizen do when trying to figure out where the science is on climate change? It'd take forever to go through every document on every site and read every book and then apply this sort of method to it. My take is that sources which mislead me on basic things that I can check probably don't suddenly get more accurate in the areas that I can't. If it's a major project of the organization (as opposed to some loose cannon shot off his mouth), then that organization (or that loose cannon) is an unreliable source. This project is a major effort (later spun off to its own project and web domain ) of the http://www.oism.org/, and several of its staff (of 6 faculty and 7 regular volunteers) are the major people involved in the petition project. Your call as to loose cannon vs. institution, but it's several loose cannons from a small group.
That weeds out a couple of web sites and a few people as dubious sources, which doesn't really gain us a lot in a world with millions (billions?) of web sites and billions of web pages.
But we can go another step and consider folks who cite the petition project as showing what the project claimed. As I've shown, it doesn't take much research to find that the project's claims don't match what is really there. So, people and sources that cite it uncritically are at least not doing homework on what they cite to me. I do mention a number of things in chatting with a friend over a beer that I've never researched (life being short already) but that I just heard somewhere. Fine. But it does mean that in those areas I'd be a poor person to try to learn the topic from. Not that I (or those petition-citing sources) are bad folks, but we haven't done homework in those areas. Doing a web search on '31,000 scientists' brings up a ton of hits (something like 40,000). On the first two pages citing the petition uncritically (or even enthusiastically) are:
http://www.worldnetdaily.com/index.php?fa=PAGE.view&pageId=64734
Cites as an 'exclusive', not an editorial. Bob Unruh
http://www.newsbusters.org/blogs/noel-sheppard/2008/05/18/31-000-scientists-rejecting-global-warming-theory-be-named-monday
blog, Noel Sheppard.
http://tadcronn.wordpress.com/2008/05/27/global-warming-consensus-31000-scientists-disagree/
http://www.uncommondescent.com/education/beneficial-natural-warming-31000-scientists/
http://www.canadafreepress.com/index.php/article/3214
Dennis Avery
As best I can see, none are editorials or opinion when at news outlets.
I'll start a summary of unreliable sources, probably at my web site rather than here. Please do suggest other candidates, to the same address. To be a candidate, the site or person must: make an error that can be detected by a nonspecialist -- on an important point to his argument (a primary dubious source), or, cite a primary dubious source uncritically. Not all errors count; for example, in my first paper a word was supposed to be 'parameter', but it got published with 'satellite'. An error, but it didn't affect the argument about ice sheets. For now, it also doesn't count that one person using highly specialized methods detected an error in another highly skilled person's work. I'm going for that citizen level where people can throughly check things out for themselves. That's why, for instance, I have so many links here and the notes are excruciatingly long. Check everything out yourself. If you think I'm wrong, send me your reasons why, with at least equal care to what I've done.
In part 1, we looked a bit at whether the numbers of signers was large. The petition project itself, and even more those who quote it, wants us to believe that there is 'a lot' of scientific opposition. But it turns out that most of the signers are nonscientists, much less scientists in something relevant to climate; worse, the numbers are actually quite small compared to the sizes of the fields they were mass mailing to. Junk mail rate.
For part 2 here, let's look to see whether many of the people in the AGU have signed. We'd want to do a later check whether it was mineralogists vs. atmospheric scientists, but it's a start. Since the AGU has about 50,000 members, I didn't want to try checking the whole list. But AGU fellows are a limited population. Unfortunately, it turns out that the 0.1% I mentioned was how many can be inducted per year. Ouch. There are quite a few more Fellows than I was thinking. Nevertheless, I started checking alphabetically.
Last names beginning with A: 0 of 41 fellows have signed
Last names beginning with B: 0 of 91 fellows have signed
As this is tedious and error prone (just how many 'Browns' are there? yikes. Names like Grumbine are much easier!) I turned to the list of 2008 fellows (not yet included in the full list). There are 51 new members. Checking the names there, I found 2 name matches, but ... Well, the names that matched are Charles R. Bacon and James W. Kirchner. But the Fellow Bacon is working in California and the signer Bacon is in Michigan, while the Fellow Kirchner has a PhD and the signer does not. So we're to 0 of the 51 new Fellows. (I'll note that it isn't a requirement that a Fellow, or AGU member, have a PhD. What matters is doing good work in the area (Fellow) or be studying or have studied the area (member).)
0 of the 183 AGU Fellows I've checked so far have signed the petition. If you'd like to assist the check, please do; send your results to me at plutarchspam at aim dt com. AGU's listing of fellows is at http://www.agu.org/inside/fellows.html The Petition Project's listing of signers is at http://petitionproject.org/gwdatabase/Signers_By_Last_Name.php And, by all means, do recheck my tallies for what I've checked so far.
The real point, though, is that the petition project has tried to mislead us, not the exact numbers. They want us to believe that engineers, doctors, and veterinarians (among other things) are scientists; they're not. They want us to believe that the number of signers is not 'a few', but as I've shown in parts 1 and 2, using only information that requires no special study, it in fact is only a few -- under 1% of the people they consider eligible have signed (in the areas I've checked, to be sure, but I did hit the largest groups). They want us to believe that the petition is about science, but the petition itself doesn't ask any scientific questions (check it out, pay attention to that major weasel word 'catastrophic'), and its main conclusion is actually about signing political agreements -- not science. And ... well, quite a few things, including that being dead is no bar to being on the list. Edward Teller, signer of their sample form, has been dead since 2003.
What should a citizen do when trying to figure out where the science is on climate change? It'd take forever to go through every document on every site and read every book and then apply this sort of method to it. My take is that sources which mislead me on basic things that I can check probably don't suddenly get more accurate in the areas that I can't. If it's a major project of the organization (as opposed to some loose cannon shot off his mouth), then that organization (or that loose cannon) is an unreliable source. This project is a major effort (later spun off to its own project and web domain ) of the http://www.oism.org/, and several of its staff (of 6 faculty and 7 regular volunteers) are the major people involved in the petition project. Your call as to loose cannon vs. institution, but it's several loose cannons from a small group.
That weeds out a couple of web sites and a few people as dubious sources, which doesn't really gain us a lot in a world with millions (billions?) of web sites and billions of web pages.
But we can go another step and consider folks who cite the petition project as showing what the project claimed. As I've shown, it doesn't take much research to find that the project's claims don't match what is really there. So, people and sources that cite it uncritically are at least not doing homework on what they cite to me. I do mention a number of things in chatting with a friend over a beer that I've never researched (life being short already) but that I just heard somewhere. Fine. But it does mean that in those areas I'd be a poor person to try to learn the topic from. Not that I (or those petition-citing sources) are bad folks, but we haven't done homework in those areas. Doing a web search on '31,000 scientists' brings up a ton of hits (something like 40,000). On the first two pages citing the petition uncritically (or even enthusiastically) are:
http://www.worldnetdaily.com/index.php?fa=PAGE.view&pageId=64734
Cites as an 'exclusive', not an editorial. Bob Unruh
http://www.newsbusters.org/blogs/noel-sheppard/2008/05/18/31-000-scientists-rejecting-global-warming-theory-be-named-monday
blog, Noel Sheppard.
http://tadcronn.wordpress.com/2008/05/27/global-warming-consensus-31000-scientists-disagree/
http://www.uncommondescent.com/education/beneficial-natural-warming-31000-scientists/
http://www.canadafreepress.com/index.php/article/3214
Dennis Avery
As best I can see, none are editorials or opinion when at news outlets.
I'll start a summary of unreliable sources, probably at my web site rather than here. Please do suggest other candidates, to the same address. To be a candidate, the site or person must: make an error that can be detected by a nonspecialist -- on an important point to his argument (a primary dubious source), or, cite a primary dubious source uncritically. Not all errors count; for example, in my first paper a word was supposed to be 'parameter', but it got published with 'satellite'. An error, but it didn't affect the argument about ice sheets. For now, it also doesn't count that one person using highly specialized methods detected an error in another highly skilled person's work. I'm going for that citizen level where people can throughly check things out for themselves. That's why, for instance, I have so many links here and the notes are excruciatingly long. Check everything out yourself. If you think I'm wrong, send me your reasons why, with at least equal care to what I've done.
24 July 2008
Petitioning on climate, part 1
Nature is quite unconcerned about what people sign on petitions, so it baffles me that folks who say they're interested in the science turn to petitions to settle matters. I figure the best way to find out about it is to turn to folks who are studying the thing you're interested in. If I'm interested in bridges, I should turn to a civil or mechanical engineer who is working on designing them, and not someone with the same degree who works on sanitation systems or aircraft engines, much less someone working on nuclear physics (interesting field, and bright folks, but ... not much concerned with bridges).
Nevertheless, such a petition is now out, 'new and improved!!!' with 31,000 signers. (Ok, the new and improved is my comment, not theirs, but having been getting their mailings off and on for over a decade, I'm more than a little jaded.) This is a chance to try out my earlier comments that one needn't be a professional to weed out some sources.
Over at http://www.petitionproject.org/gwdatabase/GWPP/Qualifications_Of_Signers.html is their commentary on the qualifications of the petition signers. One thing they mention is that:
Hmm. Right off, one needn't be a professional to notice that engineering and science are different fields. I chatted some about this earlier. Why run down engineers by calling them scientists? As they say, engineering is required to maintain (I include improve) civilization. I agree; that's why I started there. It's good, important work. But it isn't science. Even stranger is what happens when you look farther down the list -- they fail to include almost any engineering discipline in their engineering total. They include elsewhere:
Environmental Engineering (473)
Computer Science (217)
Nuclear Engineering (215)
Mechanical Engineering (2,581)
Aerospace Engineering (585)
Chemical Engineering (1,640)
Agricultural Engineering (111)
So we need to add another 5,822 to the engineering tally, making it 15,814.
Hmm. Over half the signers are engineers, it turns out.
They also seem to have no biomedical engineers or industrial engineers, a couple areas I had friends in when I was in college. (Ok, you have to know something about the fields of engineering to notice this. But it isn't that specialized a bit of knowledge.)
So, let's ask a different question (ignoring, for now, that there's no more reason to believe that engineers know climatology any more than we'd assume climatologists know engineering). Is that number of engineers a large fraction of the field? The project having conducted a massive mass mailing, they should have reached a lot of the engineers. If this is a matter they generally feel strongly about (and, as the petition notes, they're looking at people who maintain the infrastructure of civilization, and the project is claiming that this is threatened), it should be a pretty high fraction. At least, say, half.
I figure the National Academy of Engineering would be a good place to look for figures on engineers. The first result on my search for "number of engineers" was:
http://www.nae.edu/nae/naehome.nsf/Multi+Database+Search/85256DAD003F352385256F8D006130A8?OpenDocument
It noted a couple of things. One was, that about 75,000 engineers are graduating each year. Another is that 6% unemployment among engineers meant 120,000 engineers being unemployed. A little arithmetic shows us that this means there are about 2,000,000 engineers in the USA.
We have two comparisons then, to the number of graduates, and to the total population. The latter is more meaningful. Even so, the number of engineering signers represents only about 20% of a single year's graduates. This is not impressive. Compared to the total number of engineers, it represents about 0.8%. Fewer than 1 in 100 engineers has signed.
Don't take my word for those numbers, of course. Check it out yourself. The 2 million is suspisciously round. On the other hand, if something like 75,000 are graduating each year, it's hard to see that 16,000 can be a large fraction of the total number of engineers. Let me know what better figures you find.
Again with no special knowledge, let's look at the medical folks. The project is including MD, DVM, and 'medical science' in their figures here. Again, my GP is a good doctor, but I wouldn't presume that he is knowledgeable about the physics of turbulent transfer (an element of climate), any more than my turbulent transfer friend is the guy I'd expect to take care of my allergies. Anyhow, let's see how many doctors and veterinarians there are vs. the 3069 signers they have. Hmm. AMA site wasn't much help, but a general search on "number of doctors" lead me to here:
http://www.usatoday.com/news/health/2005-03-02-doctor-shortage_x.htm Which gives the current (in 2005) figure at about 800,000. For veterinarians, I went with the general search since I don't know the name of their professional society. I found at http://www.bls.gov/oco/ocos076.htm#emply a figure of 62,000. This is missing a number of fields, since I couldn't figure what all the project meant by 'medical' (maybe they're including nursing degrees? Dentists? lab technicians?). If anything, then, my 862,000 total here is an underestimate. The percentage of possible signers in this category who did sign is ... 0.3%. About 1 in 300. (If we add the 2.5 million registered nurses, that percentage gets very small indeed.)
As a general reader with no knowledge of the underlying science, this just looks very bad to me.
* The project and people citing it want me to believe that there is serious, large scale, scientific opposition to the science on climate.
But:
* Their 'big' number is grossly padded by people who have not studied climate science nor worked in it.
* It isn't a 'big' number. The fields they are including are huge. To be large, we'd have to be looking at well over 1 million signers (only 1 in 3 people the fields already named). Maybe you'd consider it large if only 1 in 10 signed. But that's still more than 10 times the rate that actually did.
* It strikes my general reader eye as strange that after listing that thus and so many PhDs signed the petition, and thus and so many climatologists signed, they don't, on their list of signers, include what the field was for the PhD. Given the numbers, it's actually possible that all the PhD signers were engineers. Not likely, but if we should be impressed by the doctorate, it'd be even more impressive if we could tell what it was in.
I've labelled this 'part 1'. Part 2 will get in to some things that you probably need some mildly specialized knowledge for. It's very mild -- things like knowing that the American Geophysical Union includes many of the people who work on climate change, and that they have designated not more than 0.1% of their members as Fellows for the consistently high quality of their work. So in part 2, I'll take a look at how many AGU Fellows have signed. As an AGU member (ordinary member) I've received the mailing myself, so I'm sure that they have as well.
Nevertheless, such a petition is now out, 'new and improved!!!' with 31,000 signers. (Ok, the new and improved is my comment, not theirs, but having been getting their mailings off and on for over a decade, I'm more than a little jaded.) This is a chance to try out my earlier comments that one needn't be a professional to weed out some sources.
Over at http://www.petitionproject.org/gwdatabase/GWPP/Qualifications_Of_Signers.html is their commentary on the qualifications of the petition signers. One thing they mention is that:
7. Engineering and general science includes 9,992 scientists trained primarily in the many engineering specialties required to maintain modern civilization and the prosperity required for all human actions, including environmental programs.
Hmm. Right off, one needn't be a professional to notice that engineering and science are different fields. I chatted some about this earlier. Why run down engineers by calling them scientists? As they say, engineering is required to maintain (I include improve) civilization. I agree; that's why I started there. It's good, important work. But it isn't science. Even stranger is what happens when you look farther down the list -- they fail to include almost any engineering discipline in their engineering total. They include elsewhere:
Environmental Engineering (473)
Computer Science (217)
Nuclear Engineering (215)
Mechanical Engineering (2,581)
Aerospace Engineering (585)
Chemical Engineering (1,640)
Agricultural Engineering (111)
So we need to add another 5,822 to the engineering tally, making it 15,814.
Hmm. Over half the signers are engineers, it turns out.
They also seem to have no biomedical engineers or industrial engineers, a couple areas I had friends in when I was in college. (Ok, you have to know something about the fields of engineering to notice this. But it isn't that specialized a bit of knowledge.)
So, let's ask a different question (ignoring, for now, that there's no more reason to believe that engineers know climatology any more than we'd assume climatologists know engineering). Is that number of engineers a large fraction of the field? The project having conducted a massive mass mailing, they should have reached a lot of the engineers. If this is a matter they generally feel strongly about (and, as the petition notes, they're looking at people who maintain the infrastructure of civilization, and the project is claiming that this is threatened), it should be a pretty high fraction. At least, say, half.
I figure the National Academy of Engineering would be a good place to look for figures on engineers. The first result on my search for "number of engineers" was:
http://www.nae.edu/nae/naehome.nsf/Multi+Database+Search/85256DAD003F352385256F8D006130A8?OpenDocument
It noted a couple of things. One was, that about 75,000 engineers are graduating each year. Another is that 6% unemployment among engineers meant 120,000 engineers being unemployed. A little arithmetic shows us that this means there are about 2,000,000 engineers in the USA.
We have two comparisons then, to the number of graduates, and to the total population. The latter is more meaningful. Even so, the number of engineering signers represents only about 20% of a single year's graduates. This is not impressive. Compared to the total number of engineers, it represents about 0.8%. Fewer than 1 in 100 engineers has signed.
Don't take my word for those numbers, of course. Check it out yourself. The 2 million is suspisciously round. On the other hand, if something like 75,000 are graduating each year, it's hard to see that 16,000 can be a large fraction of the total number of engineers. Let me know what better figures you find.
Again with no special knowledge, let's look at the medical folks. The project is including MD, DVM, and 'medical science' in their figures here. Again, my GP is a good doctor, but I wouldn't presume that he is knowledgeable about the physics of turbulent transfer (an element of climate), any more than my turbulent transfer friend is the guy I'd expect to take care of my allergies. Anyhow, let's see how many doctors and veterinarians there are vs. the 3069 signers they have. Hmm. AMA site wasn't much help, but a general search on "number of doctors" lead me to here:
http://www.usatoday.com/news/health/2005-03-02-doctor-shortage_x.htm Which gives the current (in 2005) figure at about 800,000. For veterinarians, I went with the general search since I don't know the name of their professional society. I found at http://www.bls.gov/oco/ocos076.htm#emply a figure of 62,000. This is missing a number of fields, since I couldn't figure what all the project meant by 'medical' (maybe they're including nursing degrees? Dentists? lab technicians?). If anything, then, my 862,000 total here is an underestimate. The percentage of possible signers in this category who did sign is ... 0.3%. About 1 in 300. (If we add the 2.5 million registered nurses, that percentage gets very small indeed.)
As a general reader with no knowledge of the underlying science, this just looks very bad to me.
* The project and people citing it want me to believe that there is serious, large scale, scientific opposition to the science on climate.
But:
* Their 'big' number is grossly padded by people who have not studied climate science nor worked in it.
* It isn't a 'big' number. The fields they are including are huge. To be large, we'd have to be looking at well over 1 million signers (only 1 in 3 people the fields already named). Maybe you'd consider it large if only 1 in 10 signed. But that's still more than 10 times the rate that actually did.
* It strikes my general reader eye as strange that after listing that thus and so many PhDs signed the petition, and thus and so many climatologists signed, they don't, on their list of signers, include what the field was for the PhD. Given the numbers, it's actually possible that all the PhD signers were engineers. Not likely, but if we should be impressed by the doctorate, it'd be even more impressive if we could tell what it was in.
I've labelled this 'part 1'. Part 2 will get in to some things that you probably need some mildly specialized knowledge for. It's very mild -- things like knowing that the American Geophysical Union includes many of the people who work on climate change, and that they have designated not more than 0.1% of their members as Fellows for the consistently high quality of their work. So in part 2, I'll take a look at how many AGU Fellows have signed. As an AGU member (ordinary member) I've received the mailing myself, so I'm sure that they have as well.
23 July 2008
What is climate?
This question is one I've never been satisfied with the answers to. That probably means that there's some good science to be done coming up with a solid answer to is. Probably the best description, though not a definition, is from Robert Heinlein: "Climate is what you expect. Weather is what you get." What is missing from the description is how to decide what to expect.
Some of it, though, works very well as a practical matter as well. If you measure a temperature somewhere (my back yard at 12:30 PM), you have observed weather -- what we got at the instant, in the exact location, that we took the measurement. This is useful to know in its own right since what we experience directly as we live our lives is weather. If my backyard thermometer showed 95 F and humid, I know that it's a good time to read a book instead of do major weeding.
If I take readings of my back yard temperature for every July 23rd for the last bunch (project: how many? Why that many and not half as many or twice as many?) of years, and average them, then I have a notion of the expectation value (a formal process from statistics which you can study to answer my questions of how many years to average). This gives me an estimate of the temperature to expect -- the July 23rd temperature climate for my yard.
Weather is made of quite a few different things beyond temperature, so climate must be as well. Beyond temperature, we have expectations about the wind speed and direction (usually pretty mild around me, and mostly from the west), how often rain falls and how much falls when it does, how cloudy it will be, how often there is lightning, how deep the ground freezes in winter, ...
Given this, if you see someone say that a weather event -- a single storm somewhere, a cold temperature in some modest area (and compared to the globe, the US is a modest area) has proven or disproven something about climate, you know they're wrong. It's also why you'll see many scientists talking about climate change rather than global warming. Temperature is only one part of the climate system. Temperature, on the other hand, is one of the easiest things to measure, so many climate studies do focus on that. The science problem, though, is still the whole climate system.
Some of it, though, works very well as a practical matter as well. If you measure a temperature somewhere (my back yard at 12:30 PM), you have observed weather -- what we got at the instant, in the exact location, that we took the measurement. This is useful to know in its own right since what we experience directly as we live our lives is weather. If my backyard thermometer showed 95 F and humid, I know that it's a good time to read a book instead of do major weeding.
If I take readings of my back yard temperature for every July 23rd for the last bunch (project: how many? Why that many and not half as many or twice as many?) of years, and average them, then I have a notion of the expectation value (a formal process from statistics which you can study to answer my questions of how many years to average). This gives me an estimate of the temperature to expect -- the July 23rd temperature climate for my yard.
Weather is made of quite a few different things beyond temperature, so climate must be as well. Beyond temperature, we have expectations about the wind speed and direction (usually pretty mild around me, and mostly from the west), how often rain falls and how much falls when it does, how cloudy it will be, how often there is lightning, how deep the ground freezes in winter, ...
Given this, if you see someone say that a weather event -- a single storm somewhere, a cold temperature in some modest area (and compared to the globe, the US is a modest area) has proven or disproven something about climate, you know they're wrong. It's also why you'll see many scientists talking about climate change rather than global warming. Temperature is only one part of the climate system. Temperature, on the other hand, is one of the easiest things to measure, so many climate studies do focus on that. The science problem, though, is still the whole climate system.
22 July 2008
Projects
My project folder has gotten unwieldy, so some things will show up here from there. The project folder (ok, it's now a shelf or two of bookcase) started when I realized that I had far more ideas than time to complete them. So I started making notes on the ideas so that at least I wouldn't forget what they were. But I'd also clear the brain a little to have room for new ideas. Some of those ideas have been published in the scientific literature, and some have sat quietly for upwards of 20 years.
A different sort of 'project' that will show up is where I'll suggest that you try something, or challenge you to answer something. In the former case, I probably know the answer and give some fair pointers to how to finish it. In the latter, I may not have the answer either; but it is a good question to have one for. Maybe some would be publishable in the scientific literature.
Probably a number of these will lend themselves to science fair projects.
Where I mention a project in a science note (like, say, the simplest meaningful climate model note) it may well also be that I don't expect you to take my word for things. If I'm talking science, you can do things yourself and come up with the same answer. I think it's a good thing to take the time and wrestle some with the guts of a problem. You'll understand a lot more that way (certainly I do). Plus, maybe I made a mistake and you can be the one to point it out. (In science this is normal and welcome. But you do have to provide more than 'ha ha, you're sooo wrong'.)
A different sort of 'project' that will show up is where I'll suggest that you try something, or challenge you to answer something. In the former case, I probably know the answer and give some fair pointers to how to finish it. In the latter, I may not have the answer either; but it is a good question to have one for. Maybe some would be publishable in the scientific literature.
Probably a number of these will lend themselves to science fair projects.
Where I mention a project in a science note (like, say, the simplest meaningful climate model note) it may well also be that I don't expect you to take my word for things. If I'm talking science, you can do things yourself and come up with the same answer. I think it's a good thing to take the time and wrestle some with the guts of a problem. You'll understand a lot more that way (certainly I do). Plus, maybe I made a mistake and you can be the one to point it out. (In science this is normal and welcome. But you do have to provide more than 'ha ha, you're sooo wrong'.)
21 July 2008
Climate is always changing
The subject line is a comment that surface surprisingly often in the literature of folks who want to deny that climate is changing, or if it isn't, that any of it is due to human activity, or if it is, then it will be good for us. Whatever. The science of interest here is the notion of climate change, how fast, how much, how often, and the like. The human side of concern ... we'll get to a bit of that as well.
As we look through the period where we have thermometers (the last 100 or so years) recording temperatures, we see that there are indeed changes from year to year (though a year is too short really to call climate) and decade to decade (a better period to average over). But this includes the period of significant human activity (the now 6+ billion of us), so doesn't necessarily tell us a lot about what the climate does without human effects.
For longer range, say the last 600-2000 years, we have climate proxies that tell us about climate without being thermometers. Tree rings and ice cores are two such sources of proxies. When we look here, we see that climate does change decade to decade, century to century, and even millennium to millenium. The changes are small, tenths of a degree for the global average (and the longer a period you average over, the smaller the changes). But they're observable and present.
Even longer term, we still have ice cores (to 800,000 years ago), and then also start looking at marine sediments (to about 100,000,000 years ago). We see here that climate still changes, even on 10,000 to 10,000,000 year time scales. A very large change, 5 C or so global average, is associated with the northern hemisphere ice age cycle. About as much is associated with the start of the Antarctic ice cap about 35 million years ago.
The exact causes for the changes are a subject of study with some good answers and some not as confident. They include carbon dioxide (greenhouse gas) changes, orbital variations (the earth's orbit isn't exactly constant), continental drift, and land surface changes.
So what do we need to consider as humans with human interests regarding climate? As scientists, we want to understand everything, through all of time. But as citizens thinking about policy, we can look at a few things. One thing is, although there have been large changes to climate before, humans weren't around for it, certainly not 6+ billion of us, many living in large cities near the ocean. Another is, these large climate changes were also associated with large extinctions. We might not want to cause climate change sufficient to drive a large extinction. During the glacial to interglacial warming 10-18,000 years ago, global human population was likely only a few million, and were largely nomadic. So when climate got bad in one area, they simply moved (or died). Today, with 6+ billion people occupying the earth in stationary cities, it'd be difficult to move out of the way if climate got bad where you were.
Perhaps the strongest indicator of our time scale of concern is human life. If change were to be small over 70 years, we might not be concerned as little would be different between our birth and death. More quickly, we might want to ensure that there was reasonable stability between the time our kids were born and the time they reached adulthood, 20ish years. Given the two, 'a few decades' becomes our time range. Cities also point us towards the few decade time scale -- it is on this scale that urban infrastructures are built and rebuilt. If changes are slow enough that 'all' we have to do it rebuild the city further inland over the next 50 years, for instance, then relatively simple practices could get us there (but this would require some consideration on how to carry it out, as people who live now in the area marked not to be rebuilt might object!).
So, while I'm very interested as a scientist in, for instance, the 100,000 year cycles of the ice ages (my first scientific paper was on it), it's just too slow to be a concern to me as a citizen. As a citizen, I'd as soon that scientists did understand the 100,000 year cycle -- the more that is understood, the more likely that good estimates can be made of the futures. But the estimates that matter are those for the next few decades to maybe a century or two.
As we look through the period where we have thermometers (the last 100 or so years) recording temperatures, we see that there are indeed changes from year to year (though a year is too short really to call climate) and decade to decade (a better period to average over). But this includes the period of significant human activity (the now 6+ billion of us), so doesn't necessarily tell us a lot about what the climate does without human effects.
For longer range, say the last 600-2000 years, we have climate proxies that tell us about climate without being thermometers. Tree rings and ice cores are two such sources of proxies. When we look here, we see that climate does change decade to decade, century to century, and even millennium to millenium. The changes are small, tenths of a degree for the global average (and the longer a period you average over, the smaller the changes). But they're observable and present.
Even longer term, we still have ice cores (to 800,000 years ago), and then also start looking at marine sediments (to about 100,000,000 years ago). We see here that climate still changes, even on 10,000 to 10,000,000 year time scales. A very large change, 5 C or so global average, is associated with the northern hemisphere ice age cycle. About as much is associated with the start of the Antarctic ice cap about 35 million years ago.
The exact causes for the changes are a subject of study with some good answers and some not as confident. They include carbon dioxide (greenhouse gas) changes, orbital variations (the earth's orbit isn't exactly constant), continental drift, and land surface changes.
So what do we need to consider as humans with human interests regarding climate? As scientists, we want to understand everything, through all of time. But as citizens thinking about policy, we can look at a few things. One thing is, although there have been large changes to climate before, humans weren't around for it, certainly not 6+ billion of us, many living in large cities near the ocean. Another is, these large climate changes were also associated with large extinctions. We might not want to cause climate change sufficient to drive a large extinction. During the glacial to interglacial warming 10-18,000 years ago, global human population was likely only a few million, and were largely nomadic. So when climate got bad in one area, they simply moved (or died). Today, with 6+ billion people occupying the earth in stationary cities, it'd be difficult to move out of the way if climate got bad where you were.
Perhaps the strongest indicator of our time scale of concern is human life. If change were to be small over 70 years, we might not be concerned as little would be different between our birth and death. More quickly, we might want to ensure that there was reasonable stability between the time our kids were born and the time they reached adulthood, 20ish years. Given the two, 'a few decades' becomes our time range. Cities also point us towards the few decade time scale -- it is on this scale that urban infrastructures are built and rebuilt. If changes are slow enough that 'all' we have to do it rebuild the city further inland over the next 50 years, for instance, then relatively simple practices could get us there (but this would require some consideration on how to carry it out, as people who live now in the area marked not to be rebuilt might object!).
So, while I'm very interested as a scientist in, for instance, the 100,000 year cycles of the ice ages (my first scientific paper was on it), it's just too slow to be a concern to me as a citizen. As a citizen, I'd as soon that scientists did understand the 100,000 year cycle -- the more that is understood, the more likely that good estimates can be made of the futures. But the estimates that matter are those for the next few decades to maybe a century or two.
14 July 2008
Climate confusion
Part 3 with Dave's comments
Thirdly you have global warming, and then you have "Man Made global warming" and people start getting defensive if all of a sudden you start blaming them for the impeding end of the world unless "we all change the way we live and our lives now and this is how you do it".
Fourthly you see it in mainstream media now all too much: Everything and anything that is out of the ordinary now has some relationship to global warming, no matter how ridiculous.
So here I sit with 27,000 scientists saying one thing and another 27,000 scoffing at the huliboo. Who do I believe? I have seen calm rational debate from both sides. We've had global warming before. It would seem hard to argue that man hasn't had some effect but to what degree?
Agreed about the media thing. It's one of the things which irritates the scientists who are trying to communicate accurate, careful, correct information. People hear wild claims in the media, and then when we discuss what we really know and how well, we don't get believed (since we're not as extreme as the media reports, it's no story). ('we' by the way doesn't exactly include me. I haven't talked to the media for a long time, and it wasn't about this. Still, I do know folks who get quoted.)
One thing for you to do, with the 27,000 on either side of you, is to start looking at what they're scientists of. It turns out that the 27k saying that climate is changing and part of the reason is human activity are climate scientists, while the 27k disagreeing are doctors, chemists, nuclear physicists, ... But do the checking yourself. There's a petition, for instance, with over 17,000 signers, but very few of them are in climate sciences (but check me on that). If your mechanic says your car needs a new belt, as do the several other mechanics you take the car to, while a bunch of doctors you know say that it doesn't, do you get the belt or not? I get the belt. Being knowledgeable (about something) isn't sufficient; you have to be knowledgeable about the thing at hand.
A different thing, if you encounter folks trying to stampede you into particular actions (whether to avert climate change, or to ignore it) is to put a focus on Where's the science? If they're going on about how if you don't do everything they say 'we're all gonna die', or if they go on about if we do do anything 'we'll all be unemployed', well, no science to either claim. Move on. This is amazingly (depressingly) effective at screening out the stampeders. The very few comments in the vein of 'this is what we understand, therefore the following action would be a good idea' you can study and decide whether you agree.
I do a number of things that are advised for climate change reduction/prevention/etc., not because of any stampeder, but because it saves me money to drive a more efficient car, have a better-insulated house, etc. If it happens that also this does good for the environment, great.
Thirdly you have global warming, and then you have "Man Made global warming" and people start getting defensive if all of a sudden you start blaming them for the impeding end of the world unless "we all change the way we live and our lives now and this is how you do it".
Fourthly you see it in mainstream media now all too much: Everything and anything that is out of the ordinary now has some relationship to global warming, no matter how ridiculous.
So here I sit with 27,000 scientists saying one thing and another 27,000 scoffing at the huliboo. Who do I believe? I have seen calm rational debate from both sides. We've had global warming before. It would seem hard to argue that man hasn't had some effect but to what degree?
Agreed about the media thing. It's one of the things which irritates the scientists who are trying to communicate accurate, careful, correct information. People hear wild claims in the media, and then when we discuss what we really know and how well, we don't get believed (since we're not as extreme as the media reports, it's no story). ('we' by the way doesn't exactly include me. I haven't talked to the media for a long time, and it wasn't about this. Still, I do know folks who get quoted.)
One thing for you to do, with the 27,000 on either side of you, is to start looking at what they're scientists of. It turns out that the 27k saying that climate is changing and part of the reason is human activity are climate scientists, while the 27k disagreeing are doctors, chemists, nuclear physicists, ... But do the checking yourself. There's a petition, for instance, with over 17,000 signers, but very few of them are in climate sciences (but check me on that). If your mechanic says your car needs a new belt, as do the several other mechanics you take the car to, while a bunch of doctors you know say that it doesn't, do you get the belt or not? I get the belt. Being knowledgeable (about something) isn't sufficient; you have to be knowledgeable about the thing at hand.
A different thing, if you encounter folks trying to stampede you into particular actions (whether to avert climate change, or to ignore it) is to put a focus on Where's the science? If they're going on about how if you don't do everything they say 'we're all gonna die', or if they go on about if we do do anything 'we'll all be unemployed', well, no science to either claim. Move on. This is amazingly (depressingly) effective at screening out the stampeders. The very few comments in the vein of 'this is what we understand, therefore the following action would be a good idea' you can study and decide whether you agree.
I do a number of things that are advised for climate change reduction/prevention/etc., not because of any stampeder, but because it saves me money to drive a more efficient car, have a better-insulated house, etc. If it happens that also this does good for the environment, great.
10 July 2008
Introducing the Atmosphere
A while back I introduced the ocean. a bit. Time for the atmosphere, which turns out to be much simpler than the ocean, or maybe that just is a matter of being more subtle.
In the ocean, we have names for areas bounded (usually) by land. This doesn't work for the atmosphere, since it covers the whole earth. It does turn out, however, that the circulation itself (as for the Southern Ocean) helps divide the atmosphere. For a first approximation, little air crosses the equator. (Some does, to be sure.) So we can divide the atmosphere to northern and southern hemisphere circulations. Even though the two hemispheres are greatly different in their amounts and distribution of land and ocean, it turns out that their major circulation is quite similar.
In both hemispheres, air rises from the equator, move towards higher latitude at elevation (5-15 km, 3-9 miles up) and then sinks to the surface around 30 degrees latitude (north or south). The surface circulation is from that sinking latitude back towards the equator. This is the Hadley cell. There's a similar cell between about 60 degrees latitude and the pole, called the Ferrel cell. In between the two is not so much a cell as a storm zone.
A couple of questions I haven't seen firmly answered (I do have leads on a couple of papers, but haven't read them yet) are: Why are the circulations so similar between the hemispheres? Why are there 3 zones of circulation instead of 2, 4, 5, 75, ...?
In the vertical ... how high is up? :-) There's actually a way of approaching this by way of a different question:
What is the atmosphere made of? If we sample air all around the world, and through all levels of the atmosphere, we discover a few striking things. First, only 3 gases account for almost the entire atmosphere -- Nitrogen (N2), Oxygen (O2), and Argon (Ar). They are, in order, 78%, 21%, and 1% of the atmosphere in terms of counting molecules, and 76%, 23%, and 1% by mass. Note that these figures have been rounded, but also note that they do add to 100%. A further feature is that this proportion is constant throughout the atmosphere -- until you get to about 100 km (about 60 miles) up. Above that point heavier gases separate from lighter ones.
So that's our answer to 'how high is up?' -- about 100 km.
But back to the matter of what the atmosphere is made of. We've all heard about water (H2O), Carbon dioxide (CO2), and Ozone (O3) and how important they are. They are indeed important. But, added up through the atmosphere, they account for only about 0.24% of the molecules. Considering all gases, only about 1 in 400 molecules is not one of the big 3 of Nitrogen, Oxygen, or Argon.
Yet it is these other, rare, molecules which account for almost all the interesting processes in the atmosphere! This includes rain, hurricanes, the fact that the earth is not frozen, protecting surface life from solar ultraviolet, constructing the stratosphere, ...
Ok, the stratosphere brings us back to the vertical structure of the atmosphere. Starting from the surface, we have the troposphere. Here's where almost all the weather happens, and temperatures generally decrease with height. (So it's usually cooler in the mountains than the flat land around them.) In the stratosphere, temperatures are constant or increasing with height. Above this is the mesosphere, where temperatures go back to decreasing with height. The top of the mesosphere is that 100 km (or so) boundary. Above this, things get very different, and usually are studied by people who aren't meteorologists or climatologists. (Aeronomers, chemists, physicists instead.)
The stratosphere being a warm place, compared to the air above or below it, is because of the ozone absorbing ultraviolet. Without the ozone (and the chemistry that maintains that molecule), there's nothing to be absorbing energy to warm the layer. At most, ozone is about 12 parts per million of the molecules in that layer (0.0012 % !)
Since my first cut is always to take a look at the largest scale things, the most common, and such, we're already done. 3 molecules make up almost all of the atmosphere (N2, O2, Ar), there are 3 circulation zones between equator and pole in each hemisphere, there are 3 layers in the vertical, and the atmosphere goes up about 100 km.
To understand most of what's interesting, we have to get much more subtle. Always a fun and interesting thing to find that understanding some very small part of a big system will let us understand a lot about that large system.
In the ocean, we have names for areas bounded (usually) by land. This doesn't work for the atmosphere, since it covers the whole earth. It does turn out, however, that the circulation itself (as for the Southern Ocean) helps divide the atmosphere. For a first approximation, little air crosses the equator. (Some does, to be sure.) So we can divide the atmosphere to northern and southern hemisphere circulations. Even though the two hemispheres are greatly different in their amounts and distribution of land and ocean, it turns out that their major circulation is quite similar.
In both hemispheres, air rises from the equator, move towards higher latitude at elevation (5-15 km, 3-9 miles up) and then sinks to the surface around 30 degrees latitude (north or south). The surface circulation is from that sinking latitude back towards the equator. This is the Hadley cell. There's a similar cell between about 60 degrees latitude and the pole, called the Ferrel cell. In between the two is not so much a cell as a storm zone.
A couple of questions I haven't seen firmly answered (I do have leads on a couple of papers, but haven't read them yet) are: Why are the circulations so similar between the hemispheres? Why are there 3 zones of circulation instead of 2, 4, 5, 75, ...?
In the vertical ... how high is up? :-) There's actually a way of approaching this by way of a different question:
What is the atmosphere made of? If we sample air all around the world, and through all levels of the atmosphere, we discover a few striking things. First, only 3 gases account for almost the entire atmosphere -- Nitrogen (N2), Oxygen (O2), and Argon (Ar). They are, in order, 78%, 21%, and 1% of the atmosphere in terms of counting molecules, and 76%, 23%, and 1% by mass. Note that these figures have been rounded, but also note that they do add to 100%. A further feature is that this proportion is constant throughout the atmosphere -- until you get to about 100 km (about 60 miles) up. Above that point heavier gases separate from lighter ones.
So that's our answer to 'how high is up?' -- about 100 km.
But back to the matter of what the atmosphere is made of. We've all heard about water (H2O), Carbon dioxide (CO2), and Ozone (O3) and how important they are. They are indeed important. But, added up through the atmosphere, they account for only about 0.24% of the molecules. Considering all gases, only about 1 in 400 molecules is not one of the big 3 of Nitrogen, Oxygen, or Argon.
Yet it is these other, rare, molecules which account for almost all the interesting processes in the atmosphere! This includes rain, hurricanes, the fact that the earth is not frozen, protecting surface life from solar ultraviolet, constructing the stratosphere, ...
Ok, the stratosphere brings us back to the vertical structure of the atmosphere. Starting from the surface, we have the troposphere. Here's where almost all the weather happens, and temperatures generally decrease with height. (So it's usually cooler in the mountains than the flat land around them.) In the stratosphere, temperatures are constant or increasing with height. Above this is the mesosphere, where temperatures go back to decreasing with height. The top of the mesosphere is that 100 km (or so) boundary. Above this, things get very different, and usually are studied by people who aren't meteorologists or climatologists. (Aeronomers, chemists, physicists instead.)
The stratosphere being a warm place, compared to the air above or below it, is because of the ozone absorbing ultraviolet. Without the ozone (and the chemistry that maintains that molecule), there's nothing to be absorbing energy to warm the layer. At most, ozone is about 12 parts per million of the molecules in that layer (0.0012 % !)
Since my first cut is always to take a look at the largest scale things, the most common, and such, we're already done. 3 molecules make up almost all of the atmosphere (N2, O2, Ar), there are 3 circulation zones between equator and pole in each hemisphere, there are 3 layers in the vertical, and the atmosphere goes up about 100 km.
To understand most of what's interesting, we have to get much more subtle. Always a fun and interesting thing to find that understanding some very small part of a big system will let us understand a lot about that large system.
09 July 2008
The question place #1
I'll put this up as a collecting spot for questions. If you have questions about science, drop them here. Some I'll be able to answer in new posts, some, maybe readers here will be able to make progress with.
07 July 2008
Science not politics
Continuing with Dave's comments about climate science:
Secondly you have a topic that's polarized many different groups, and many an individual will merely argue a point because a group they might relate to is arguing the same point.
Many people have vested interests relating to climate change and thoughts about what, if anything, to do about it. That does produce politics, in that groups of people with interests act politically.
But the science is the science, and respects no party, no nation, no religion, etc.
This does make for the problem that groups with interests other than explaining and discussing the best science also establish web sites, write editorials, produce shows, etc. to propagandize their views, distorting and lying about the science along the way. So if you're interested in the science, you have to work harder to find it than in something which doesn't scare people. You also have to work harder to disentangle the parts of an article that are science from those which are opinion, wishful thinking, and such.
One thing which I think is helpful in deciding about sources is to, first, hold your nose about their political viewpoints. This can be hard when the politics are greatly different from yours, but bear with it. As you read through, look for scientific claims, or claims which the author thinks are scientific. As you find them, go hit the literature on the topic and see if the author has represented the point correctly. It may sound like a lot of work, but in practice, most web sites which are more concerned about their politics than the science display this fairly quickly by lies and distortions, and some are at an extremely basic level. Basic enough that you can check the truth of it by looking at a textbook from 30 years ago (before the topic was getting nearly as much press, but well after the scientific basics were understood). If not an outright lie, very often what you'll see is a quote selected from a scientific article and removed from its context. Once you find the context, you see that the original author's intent was quite different than the bit quoted.
As you proceed with this, you'll find some sites are very prone to distortion or lying, and some are, if not doing it, then at least only doing it on such a subtle level that you can't detect it. Eliminating the most egregious (and those who quote the same lines -- there's very little originality, so learning a few facts suffices to eliminate a lot of the bad sites) narrows the field greatly, and productively. The difficult part is where you have to eliminate sites whose politics you generally like. On the other hand, if you want your car fixed, you go to your mechanic, not to your representative (aside from the times they're the same person :-). Scientists working in the area are better sources than political groups anyhow.
After you start to understand the science, you have separate questions. (for all 'you', including me). I don't think the responses are dictated by the science. Once you understand the science and the probable outcomes, now you have to ask the questions of what is morally appropriate, what is politically appropriate, what is economically appropriate, and so on, by way of responses (including 'do nothing'). Different people, even if agreed on the science, will (and should) disagree here. But, if the discussion were to be based on our best understanding of the science, I think we'd be far better off.
Secondly you have a topic that's polarized many different groups, and many an individual will merely argue a point because a group they might relate to is arguing the same point.
Many people have vested interests relating to climate change and thoughts about what, if anything, to do about it. That does produce politics, in that groups of people with interests act politically.
But the science is the science, and respects no party, no nation, no religion, etc.
This does make for the problem that groups with interests other than explaining and discussing the best science also establish web sites, write editorials, produce shows, etc. to propagandize their views, distorting and lying about the science along the way. So if you're interested in the science, you have to work harder to find it than in something which doesn't scare people. You also have to work harder to disentangle the parts of an article that are science from those which are opinion, wishful thinking, and such.
One thing which I think is helpful in deciding about sources is to, first, hold your nose about their political viewpoints. This can be hard when the politics are greatly different from yours, but bear with it. As you read through, look for scientific claims, or claims which the author thinks are scientific. As you find them, go hit the literature on the topic and see if the author has represented the point correctly. It may sound like a lot of work, but in practice, most web sites which are more concerned about their politics than the science display this fairly quickly by lies and distortions, and some are at an extremely basic level. Basic enough that you can check the truth of it by looking at a textbook from 30 years ago (before the topic was getting nearly as much press, but well after the scientific basics were understood). If not an outright lie, very often what you'll see is a quote selected from a scientific article and removed from its context. Once you find the context, you see that the original author's intent was quite different than the bit quoted.
As you proceed with this, you'll find some sites are very prone to distortion or lying, and some are, if not doing it, then at least only doing it on such a subtle level that you can't detect it. Eliminating the most egregious (and those who quote the same lines -- there's very little originality, so learning a few facts suffices to eliminate a lot of the bad sites) narrows the field greatly, and productively. The difficult part is where you have to eliminate sites whose politics you generally like. On the other hand, if you want your car fixed, you go to your mechanic, not to your representative (aside from the times they're the same person :-). Scientists working in the area are better sources than political groups anyhow.
After you start to understand the science, you have separate questions. (for all 'you', including me). I don't think the responses are dictated by the science. Once you understand the science and the probable outcomes, now you have to ask the questions of what is morally appropriate, what is politically appropriate, what is economically appropriate, and so on, by way of responses (including 'do nothing'). Different people, even if agreed on the science, will (and should) disagree here. But, if the discussion were to be based on our best understanding of the science, I think we'd be far better off.
04 July 2008
Happy 4th of July!
4th of July now, I'm back from my travels, and celebrating the date. One thing I do on the 4th is to re-read the Declaration of Independence and the Constitution. Actually, not so much the declaration as the Constitution. While the Declaration did prompt the following events, it is the Constitution which really defined who we were or at least wanted to be. Much of the better part our history is a matter of applying the ideals of the Constitution to a greater fraction of the people.
I've also started fooling with genealogy in the past year, most of which I won't inflict on you as it's really only of interest to me (and perhaps some of my relatives). (But the story of my ancestor at the bombing of Fort McHenry ... surely that's of interest to all? ... well, maybe not.) One thing I've taken as given is that, ultimately, I'm related to everybody, and have ancestors from everywhere. One thing that means is that in every war, I figure I have relatives on both sides. For our revolution, this turns out to be true within a single family. My great-to-the-something ancestor Zeboath Brittain and the other two older brothers fought for the revolution, while the three younger brothers fought for the Empire. After the Empire lost, they moved to Nova Scotia. Dad, William, was also an empire loyalist, outspokenly so and jailed for it a time or two during the war. But he stayed (along with his wife, who was apparently equally vocal in favor of the revolution) after the war settled down.
It's a reminder, though, that the decision to revolt was not very clear-cut at the time. Rather few participated on either side, and among those families that did, it doesn't seem very one-sided as to which side they'd go for. This is part of the answer, I guess, as to why Canada neither joined in the rebellion, nor conducted their own later (by the way, happy Canada day 3 days late). A different genealogical perspective is that post-revolution, the life expectancy of USAns plummeted. Or maybe that's just my ancestors (though I doubt it).
Since we're in July, also a happy Bastille day (early, July 14th) to my French friends. (My known French ancestors were out of the country before the revolution; but 60+% of my ancestors are still unknown, so I'll assume some were still there.) During my recent vacation/working trip, I was in France (Paris and Perros-Guirec Brittany) for a week. Walked down from the Arc de Triumphe to the Place de la Concorde, among other things. No visit to the Bastille, but my wife and I did visit Versailles, which had its own drama in the Revolution. It's more than a little odd to think about how the support of France (Louis XVI, draining coffers and raising taxes) for our revolution helped bring about its revolution. Worked out better for us than France, or at least Louis.
Anyhow, whether it's "Libertie, Egalitie, Fraternitie", "We hold these truths to be self-evident ...", "We the people of the United States of America, in order to form a more perfect union, ...", this is a good time to think about what our ideals are, the best possible arrangements for our societies is, and how to move from where we are currently to where that better situation is.
Cheers!
I've also started fooling with genealogy in the past year, most of which I won't inflict on you as it's really only of interest to me (and perhaps some of my relatives). (But the story of my ancestor at the bombing of Fort McHenry ... surely that's of interest to all? ... well, maybe not.) One thing I've taken as given is that, ultimately, I'm related to everybody, and have ancestors from everywhere. One thing that means is that in every war, I figure I have relatives on both sides. For our revolution, this turns out to be true within a single family. My great-to-the-something ancestor Zeboath Brittain and the other two older brothers fought for the revolution, while the three younger brothers fought for the Empire. After the Empire lost, they moved to Nova Scotia. Dad, William, was also an empire loyalist, outspokenly so and jailed for it a time or two during the war. But he stayed (along with his wife, who was apparently equally vocal in favor of the revolution) after the war settled down.
It's a reminder, though, that the decision to revolt was not very clear-cut at the time. Rather few participated on either side, and among those families that did, it doesn't seem very one-sided as to which side they'd go for. This is part of the answer, I guess, as to why Canada neither joined in the rebellion, nor conducted their own later (by the way, happy Canada day 3 days late). A different genealogical perspective is that post-revolution, the life expectancy of USAns plummeted. Or maybe that's just my ancestors (though I doubt it).
Since we're in July, also a happy Bastille day (early, July 14th) to my French friends. (My known French ancestors were out of the country before the revolution; but 60+% of my ancestors are still unknown, so I'll assume some were still there.) During my recent vacation/working trip, I was in France (Paris and Perros-Guirec Brittany) for a week. Walked down from the Arc de Triumphe to the Place de la Concorde, among other things. No visit to the Bastille, but my wife and I did visit Versailles, which had its own drama in the Revolution. It's more than a little odd to think about how the support of France (Louis XVI, draining coffers and raising taxes) for our revolution helped bring about its revolution. Worked out better for us than France, or at least Louis.
Anyhow, whether it's "Libertie, Egalitie, Fraternitie", "We hold these truths to be self-evident ...", "We the people of the United States of America, in order to form a more perfect union, ...", this is a good time to think about what our ideals are, the best possible arrangements for our societies is, and how to move from where we are currently to where that better situation is.
Cheers!
01 July 2008
Climate is a messy business
I'll be making a number of posts prompted by a note from Dave in a different area. It'll be a number of posts because I'd like to take some care on each of the points.
Let's start with:
This topic of global warming has alot of problems... First of all you have a complicated science. It's not likely alot of people will truly understand the science well enough to be able to argue the points.
Climate certainly is a messy business. One of the things that makes it interesting to those of us who work on it is precisely that. Wherever you look, you find something that affects climate, regardless of whether you look at permafrost, sea ice, forests, farms, rivers, factories, sunspots, volcanoes, dust, glaciers, ...
So certainly we have a complicated science and certainly few people are going to understand enough of it to argue the finer points. This is true within the science as well, as few who study volcanoes and their climate effects are going to be able to argue the finer points about the role of sea ice in climate, or vice versa.
What does an honest and interested person do then? Two things as I see it. First, not all the science involved is difficult. For those parts of the science, learn the science. Anybody who can get through normal life, cook a recipe, balance a checkbook, etc., can understand the basics. One source is Jan Schloerer's summary at http://www.radix.net/~bobg/faqs/scq.basics.html Jan was not a climate scientist, but, as I said, you don't need to be one to understand the basics. One thing he did do (see his acknowledgements, for instance) is check with people who were to ensure that he'd gotten the science right (or at least correct given the limits of writing a general audience description). I'll come back to basics in a minute.
Second, for things that aren't elementary, start looking to expert opinion. No different than if your car is acting up and you can't figure out why, or you've got something like a cold but it isn't going away like one should. You go find an auto mechanic or doctor and use their expertise. If your concern is, instead, about climate, then find some climate scientists. While there aren't that many (even counting worldwide) they do exist. And it's not that hard to find their professional understanding. You'll see it more directly in journals like Science and Nature than Scientific American or Discover. But both can be gotten fairly easily, and both include summaries of the science which are written for laymen.
You can also look to the IPCC reports, the fourth having been issued recently. The first was the best, I think, in terms of explaining the science to non-professionals. As the basics haven't changed since then, you might want to look for the first edition. The summary for policymakers, in each edition, is the most readable and aimed for non-professionals. The drawback is that it necessarily includes fewer details about the science. Nevertheless, it (the IPCC report) does represent as good a summary of the state of the science as you'll find.
Let's start with:
This topic of global warming has alot of problems... First of all you have a complicated science. It's not likely alot of people will truly understand the science well enough to be able to argue the points.
Climate certainly is a messy business. One of the things that makes it interesting to those of us who work on it is precisely that. Wherever you look, you find something that affects climate, regardless of whether you look at permafrost, sea ice, forests, farms, rivers, factories, sunspots, volcanoes, dust, glaciers, ...
So certainly we have a complicated science and certainly few people are going to understand enough of it to argue the finer points. This is true within the science as well, as few who study volcanoes and their climate effects are going to be able to argue the finer points about the role of sea ice in climate, or vice versa.
What does an honest and interested person do then? Two things as I see it. First, not all the science involved is difficult. For those parts of the science, learn the science. Anybody who can get through normal life, cook a recipe, balance a checkbook, etc., can understand the basics. One source is Jan Schloerer's summary at http://www.radix.net/~bobg/faqs/scq.basics.html Jan was not a climate scientist, but, as I said, you don't need to be one to understand the basics. One thing he did do (see his acknowledgements, for instance) is check with people who were to ensure that he'd gotten the science right (or at least correct given the limits of writing a general audience description). I'll come back to basics in a minute.
Second, for things that aren't elementary, start looking to expert opinion. No different than if your car is acting up and you can't figure out why, or you've got something like a cold but it isn't going away like one should. You go find an auto mechanic or doctor and use their expertise. If your concern is, instead, about climate, then find some climate scientists. While there aren't that many (even counting worldwide) they do exist. And it's not that hard to find their professional understanding. You'll see it more directly in journals like Science and Nature than Scientific American or Discover. But both can be gotten fairly easily, and both include summaries of the science which are written for laymen.
You can also look to the IPCC reports, the fourth having been issued recently. The first was the best, I think, in terms of explaining the science to non-professionals. As the basics haven't changed since then, you might want to look for the first edition. The summary for policymakers, in each edition, is the most readable and aimed for non-professionals. The drawback is that it necessarily includes fewer details about the science. Nevertheless, it (the IPCC report) does represent as good a summary of the state of the science as you'll find.