Saturday, February 12, 2011

Taking On Global Warming "Skeptics"

Well, this post has been a long time coming. Almost three weeks, as a matter of fact.

Before I get started, some quick news: The first departure of the 2011 offseason has happened. Packers WR coach Jimmy Robinson has accepted the same position in Dallas, and will also be named assistant head coach in Winston Moss fashion. I'm happy for him, but a bit scared, because damn has that guy got some talent to work with in Dallas. We'll see how he does. also has an excellent pair of articles today, on the ways music can frak with your mind and the worst things alien invaders regularly do. For a musician and a sci-fi fan, that's like the best day they could've picked.

Here we go. This is a long post, so feel free to stop for coffee breaks.

Or perhaps some delicious cinnamon buns.
A few weeks back, I was privileged to take part in what I might charitably call a ‘debate’ with some avowed global warming skeptics. I say ‘skeptics’ to be kind, as ‘deniers’ is a loaded word, but also because skepticism was their defining feature; they either expressed or strongly implied skepticism in the integrity of every accredited scientific outlet I presented them with, in our ability to understand anything at all (not just in climate science), and the reliability of any information at all that did not support their points. This should not be termed ‘skepticism’ in the same way that a healthy dose of critical analysis is skeptical in nature. Rather, their inability to assimilate any information contrary to their position verged on outright nihilism.

I’d love to say that these unfortunate souls are the only people who pursue climate change skepticism with unhealthy zeal, but as we well know, this is not the case. There are a lot of people out there who have been misled by information that is simply false with regards to climate change. The people who tried, and failed, to debate me brought up six or seven of these talking points. I would like to take the opportunity to go through their arguments and debunk them, one by one.

Let me first emphasize that despite the accumulated evidence for the likelihood of anthropogenic climate change, there is still plenty of room for genuine skepticism of the data, scientific disagreement and the arrival of new information. What there is no room for is taking positions that are outright, completely, flatly, indisputably wrong.

First on the list is the idea that there is a major divide in the scientific community on the issue of climate change. The argument that one of the ‘skeptics’ made, with increasing fervor and desperation every time it was debunked, was that there is a genuine, wide and contentious rift in the scientific community over whether or not anthropogenic climate change is taking place.

This in no way reflects reality. It is wrong, false and incorrect. It is simply not true.

A recent metastudy ranked climate scientists by the number of scientific papers they had published, or in other words, their expertise. The study examined 908 climate researchers who had published twenty or more papers on the subject, then determined whether each scientist was convinced by the evidence of anthropogenic climate change (ACC) or whether they were unconvinced. “Our compiled researcher list is not comprehensive nor designed to be representative of the entire climate science community,” said the paper, “[but] we have drawn researchers from the most high-profile reports and public statements about ACC. Therefore, we have likely compiled the strongest and most credentialed researchers in CE [convinced by the evidence] or UC [unconvinced by the evidence] groups.” In the case of all researchers, it is assumed that they are familiar with the evidence for climate change, unlike the unfortunate skeptic.

The study found that only one of the 50 most prolific climate researchers was unconvinced by the evidence for ACC. Just 3% of the 100 most prolific and 2.5% of the top 200 most prolific climate scientists have publicly voiced their skepticism of ACC. 97% of the top climate scientists agree with ACC, which is consistent with the most recent survey of the broader scientific community. In addition, the UE researchers were likely to have less experience and have published fewer papers then the CE researchers, and tended to be geologists instead of atmospheric scientists.

But we need them to protect us from the volcanoes!
“This finding complements direct polling of the climate researcher community, which yields qualitative and self-reported researcher expertise. Our findings capture the added dimension of the distribution of researcher expertise, quantify agreement among the highest expertise climate researchers, and provide an independent assessment of level of scientific consensus concerning ACC,” the authors write.

But what of the potential implications of the study? For example, does this mean that there is a-brace yourselves-consensus in the scientific community? I emailed one of the authors of the study, Bill R.L. Anderegg, and asked him this question.

“’Consensus’ can have many different connotations and meanings," said Anderegg. "For me at least, the question really becomes a matter of scientific confidence. Do the vast majority of scientists believe we have enough information to say (and with what certainty) that the planet is warming, due mostly to human causes, and it's going to be fairly harmful. Our study attempted to answer this and critical to answering this is making sure you examine people who know the issue (and not just any self-proclaimed expert who has little training in the area). In this case, I think the answer is a resounding yes.”

All right, all right. But what about of the population that the study surveyed? Opponents of papers like Anderegg’s frequently charge that dissenting voices are suppressed by the scientific community, after all. Is this an accurate charge?

“No, it’s not an accurate perception and I’ll explain how and why I’ve addressed it,” Anderegg told me. “We have two main ways of addressing it. The first is data-driven and the second is based around scientific culture. Using data, I asked what fields the climate contrarians had a PhD in, with the idea being that if they were similarly trained (say, mostly atmospheric scientists) as the mainstream people, then you could make a case that their ideas are being unfairly rejected at journals. They weren't. Over a third didn't have PhDs and another third were either geologists or petroleum geologists (compared to nearly half of the mainstream people being atmospheric scientists). This suggests that the contrarians at least do not have the same background training as the mainstream community.

 “Now, as to the second, the culture of science itself thrives on discussions and dissent *if you have data* to support your ideas. Each grad student dreams of being the next Einstein or the next Darwin, and the way you become famous in science is to overturn a huge paradigm......again, if you have data. It takes an immense amount of well-done science and lots of data to overturn a paradigm. Thus, for all of these reasons, I think we can say with reasonable confidence that there is relatively little unfair excluding of alternate viewpoints in climate science.”

If they’re not accusing the scientific community of stifling dissent apurpose, climate change deniers charge that the existence of a “consensus” also smothers internal debate. I asked our expert to evaluate this possibility.

“There is still much, much, much debate on the details, timing, impacts, spatial distribution of climate change within the community. What the contrarians would like there to be debate on is 1) is the planet warming and 2) are humans causing most of it? To some extent, you must have some agreement to get do productive debate/discussion,” said Anderegg.  “If scientists let the evolution-contrarians keep the level of debate on "is evolution real", then we would not have a century's wealth of evolutionary biology that has contributed to our understanding of how the world works, medical drugs to fight diseases, etc. Our study tried to send a crystal clear message that around these two questions (are things warming and are we causing most of it) that the vast majority of scientists agree about this and we should move on to other more productive and critical questions.”

Well, this seemed fairly conclusive to me. But what about the methodology of the study? Doesn’t it seem like most scientists don’t sign the public statements that we read about in the paper? Could there be, in other words, a silent majority of climate change skeptics?

It turned out that Anderegg and his fellow researchers had accounted for this as well.

“It's my hunch that most scientists, in fact, generally don't sign public statements about this sort of thing. That's probably largely because 1) scientists are generally fairly shy and conservative people that don't like to get in the public eye or go out on a limb, 2) there's no incentive to be publicly vocal as a scientist and, in fact, the more vocal you are with the media, the less time you spend publishing papers and succeeding in your field, and 3) the science is quite evident to climate scientists and many don't feel like it's their job to educate the public (and, while I disagree with them in that I think they do have a moral obligation to share their research with society, they are quite frankly right - their job is to do research).

Now, we do have a way to assess those who haven't made public statements - surveys. In fact, two separate studies with different methods did surveys of the climate science community and they come up with almost the exact same numbers that my study did - 94-97% of climate scientists think global warming is real and mostly human caused.”

Does this mean that anthropogenic climate change is a done deal, in scientific terms? And does the weight of the overwhelming majority of the scientific community necessarily mean that their side of the issue is right? Absolutely not. As Anderegg noted in a 2009 memo, scientific opinion of the day does not garnish an argument with an everlasting halo. Many theories that were supported by a majority of scientists have since proven to be untrue. But that is not a reason to automatically discount scientific evidence, as the climate change denialists would have us do. Rather, it helps us keep in mind the fact that science can be flawed and imperfect, without losing sight of the veracity of the smorgasboard of evidence that climate scientists have presented us with.


For more documentation, I invite the reader to examine some of Anderegg's other work.

"Climate Science and the Dynamics of Expert Consensus", "Moving beyond scientific agreement: an Editorial comment on 'Climate Change: a profile of US climate scientists' perspectives'" and "Diagnosis Earth: The Climate Change Debate".

No comments:

Post a Comment