What Do Scientists Think About Global Warming?

In my previous post, I mocked the common tactic of listing as many scientists as one can find opposing a scientific consensus. They do it frequently for scientists who disbelieve in man-made global warming, but also for creationism and other subjects.

Here's a list of 2,648 people whose "doubts about AIDS are publicly known," for example. It includes scientists, doctors, nutritionists, lawyers, pharmacists, engineers, and for some reason a large number of mathematicians and physicists.

By contrast, the Republicans in the Senate only came up with 650 scientists who don't believe in man-made global warming. (Here is the document (.pdf) linked to in a comment on my previous post by Ezzie with the claim that "science disagrees.")

As I pointed out in my last post, listing the number of scientists who hold position A tells us nothing useful without also listing the number of scientists who hold position not-A. (It would of course disprove the argument that NO scientists believe in A, but nobody actually makes that claim. It's a straw man argument.)

So, because I'd like to know what's likely true rather than propagandize for a point, I thought I'd look into just how many scientists really don't believe in man-made global warming as compared to the number that do.

Examining the Scientific Consensus on Climate Change (.pdf) is the most recent answer to that question that I could find. (I found it in the very well-sourced wikipedia article Scientific opinion on climate change.) Published just last month in Eos, Transactions, American Geophysical Union, a publication of the American Geophysical Union, the paper details the results of a poll of 10,257 Earth scientists (with 3,146 respondants.)

The questions:

1. When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?
2. Do you think human activity is a significant contributing factor in changing mean global temperatures?

The answers:

Results show that overall, 90% of participants answered “risen” to question 1 and 82% answered yes to question 2. In general, as the level of active research and specialization in climate science increases, so does agreement with the two primary questions (Figure 1). In our survey, the most specialized and knowledgeable respondents (with regard to climate change) are those who listed climate science as their area of expertise and who also have published more than 50% of their recent peer-reviewed papers on the subject of climate change (79 individuals in total). Of these specialists, 96.2% (76 of 79) answered “risen” to question 1 and 97.4% (75 of 77) answered yes to question 2.

They then compare these numbers to the beliefs of the general public.



Okay. So the public is divided, but the 82% of scientists and 97.4% of scientists specializing in the subject come out on the same side. Yes, it's a web survey, and yes, "is a significant contributing factor" is probably too vague. But all of the other surveys (there are several more referred to on that wikipedia page, for example) come to similar numbers.

Here's just one more:

In 2007, Harris Interactive surveyed 489 randomly selected members of either the American Meteorological Society or the American Geophysical Union for the Statistical Assessment Service (STATS) at George Mason University. The survey found 97% agreed that global temperatures have increased during the past 100 years; 84% say they personally believe human-induced warming is occurring, and 74% agree that “currently available scientific evidence” substantiates its occurrence. Only 5% believe that that human activity does not contribute to greenhouse warming; the rest are unsure; and 84% believe global climate change poses a moderate to very great danger.^[75][76]

I think it's safe to say the large majority of scientists believe in man-made global warming. Could they be wrong? Of course, anything's possible. But what could be the basis for assuming that they are wrong, let alone the extreme confidence with which many on the right make that claim? I submit it's pure wishful thinking combined with a reflexive rejection of anything the "other side" believes. Al Gore devotes his post-VP life to "spreading the gospel," ergo the gospel must be false. And did you hear about his mansion?

These scientists are aware of Martian warming, and of sunspot activity, and of all the thousand other little straws the deniers have grasped at. They are professionals in the field, and they've heard it all. But they still believe. To assume that you, a layperson, can better interpret the evidence than the majority of scientists is pure hubris. This isn't the kind of thing where everybody's opinion is equally valid. It's the kind of thing where some people are experts and most others are just talking out of their asses.

Presumably none of you deny the HIV-AIDS link, and even most of my religious readers have accepted that evolution is true, so why cling to this position? What good reason do you have? How can you be so sure?

And please, please stop with the "X number of scientists believe this!" garbage.

How Republicans Lie About Climate Change

The majority of climate scientists all over the world believe that climate change is happening, that carbon emissions are a big part of it, and that it's a big deal. Republicans? Not so much.

Here's George Will, the Republicans' version of an intellectual, in the "liberal" Washington Post:

According to the University of Illinois' Arctic Climate Research Center, global sea ice levels now equal those of 1979.

Ok, good. That's a simple, factual claim. Quite easy to check. The Washington Post's fact-checkers don't need to measure global sea ice levels -- they just need to check that the Arctic Climate Research Center says what Will says they say. And because everybody knows the Washington Post is liberal (that's sarcasm, folks) they obviously would have rushed to prove him wrong.

They don't. The ACRC:

We do not know where George Will is getting his information, but our data shows that on February 15, 1979, global sea ice area was 16.79 million sq. km and on February 15, 2009, global sea ice area was 15.45 million sq. km. Therefore, global sea ice levels are 1.34 million sq. km less in February 2009 than in February 1979. This decrease in sea ice area is roughly equal to the area of Texas, California, and Oklahoma combined.

It is disturbing that the Washington Post would publish such information without first checking the facts.

Okay, so that's just a straight-up lie. No problem, it's easy to debunk lies. But disingenuous implications are harder. Will again:

[A]ccording to the World Meteorological Organization, there has been no recorded global warming for more than a decade.

He cites his source again. Good! We can check.

Oops. The WMO:

The long-term upward trend of global warming, mostly driven by greenhouse gas emissions, is continuing. Global temperatures in 2008 are expected to be above the long-term average. The decade from 1998 to 2007 has been the warmest on record, and the global average surface temperature has risen by 0.74C since the beginning of the 20th Century. [...] "For detecting climate change you should not look at any particular year, but instead examine the trends over a sufficiently long period of time. The current trend of temperature globally is very much indicative of warming," World Meteorological Organization Secretary-General, Mr Michel Jarraud said in response to media inquiries on current temperature "anomalies".

Yes, George, if you choose the hottest year in recent memory as your baseline, most years since then will be cooler. That doesn't mean warming stopped. The decade beginning with the year you chose as your baseline has been the warmest on record.

It's hilarious listening to Republicans on climate change. When they're not outright lying, it's just total amateur hour. They'll start talking about sunspots and Martian temperatures and how that one measuring station is totally right next to a heating vent. But they don't know what they're talking about. They're just like creationists who go on and on about this fossil or that footprint and how obviously the eye is too complex to have evolved.

(It's always "obvious," too. It's not just that the majority of scientists are wrong, it's that they're OBVIOUSLY wrong. Most of the smartest and most expert people on Earth are wrong, but Joe the Plumber's got the truth. Right.)

Now there are of course some scientists who don't believe in climate change just as there are some who don't believe in evolution. It's just that they're vastly outnumbered. (Yes, Einstein was outnumbered at first. Science isn't a democracy, and sometimes the minority is right. But when they're right they can generally prove it, and win over the majority. That's what makes it science rather than, say, religion.)

Republicans love to list all the scientists they can find who don't believe in global warming. Now an honest person would then compare that number to the list of all the scientists they could find that do believe in global warming. But they don't do that. They're not interested in honesty. Their arguments are one-sided.

Project Steve is a great parody of that tactic as used by creationists. You may have seen the lists of scientists who don't believe in evolution, numbering in the hundreds. Here's one (.pdf) from The Discovery Institute. (See kids, even scientists don't believe in evolution!) Project Steve decided that they would create a list just of scientists named Steve (or variants thereof) to highlight the ridiculousness of that technique. A couple of days ago they reached a thousand. There are more scientists named Steve who believe in evolution than scientists with all names who don't. Ouch. I'm sure the folks at The Discovery Institute will change their minds based on this new evidence.

Finally, George Will again trots out the lie that the scientific community believed in global cooling just a few decades ago. Ezra Klein puts it best:

There needs to be some sort of Godwin's Law variant for conservatives who try to argue against global warming because they remember that Newsweek dipped into pop-science in the mid-70s and touted "global cooling." Call it Will's Law, after George Will, the supposedly cerebral conservative who brings this up every time he doesn't have a better column idea.

For a good summary on the global cooling myth -- an idea that took root in the popular press but never in the scientific literature -- go sit in on the free lecture provided by the folks at Real Climate. Will makes a lot of the 1975 Newsweek cover on the subject, but the more telling document is a National Academy of Sciences report from the same year. The report argued that climate change is the product of many potential forces and the state of the science wasn't yet advanced enough to discern which would prove decisive. To put it in the NAS's own words, "we do not have a good quantitative understanding of our climate machine and what determines its course. Without the fundamental understanding, it does not seem possible to predict climate." As such, they recommended "a major new program of research designed to increase our understanding of climatic change and to lay the foundation for its prediction."

Reader Poll on Global Warming

Just curious. If you wouldn't mind, please assign what chance (0% - 100%) you think that each of the following is true:

1) The Earth warmed, on average, around .75 degrees C during the 20th century.

2) The main influence of this warming was man-made greenhouse emissions.

3) Variations in solar output have had a significant influence on global warming.

4) If global warming is happening, it will have serious detrimental effects on humanity.

5) If global warming is happening, humanity is capable of halting or reversing it.

6) There was a scientific consensus on "global cooling" in the 70s.