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:
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.
* 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.