Wednesday, September 26, 2012

Matt Ridley's Hyper-moderate Climate Change Skepticism

I was pointed at Matt Ridley's article "Apocalypse Not: Here's Why You Shouldn't Worry About End Times" as an example of a well-written thoughtful take on climate change skepticism. It has the bones of a good article, but it fails to deliver.

The goal of this article is to describe a group of related arguments that have particular weaknesses in common, and to explain how to spot the weaknesses of these arguments. It does define such a group, but its definition depends on a conflation, the examples it gives actually undermine its argument, and the strategy it proposes is poor.

First, he identifies a group, warnings of impending cataclysm, and explains why it is interesting.

Consider some of the environmental cataclysms that so many experts promised were inevitable.
Yet there is no sign that experts are becoming more cautious about apocalyptic promises. If anything, the rhetoric has ramped up in recent years.

Fair enough.

True, we have encountered obstacles, public-health emergencies, and even mass tragedies. But the promised Armageddons—the thresholds that cannot be uncrossed, the tipping points that cannot be untipped, the existential threats to Life as We Know It—have consistently failed to materialize.

Strangely, he seems to be suggesting that mass tragedies are not something that we (the polity) should expend effort to understand and then argues that we should expect to have seen something that we could not possibly survive to reflect upon : our extinction. That we have never been wiped out by an asteroid is not evidence that asteroids cannot wipe us out. Just ask the dinosaurs. Oh wait, we can't because they were wiped out. (This may seem like a trivial objection, but it's not. A positive claim that something won't happen because it hasn't been observed to happen to us only holds if we could have observed it. By the nature of extinction events, you can only observe them happening to others.)

Still, if Ridley does a good job of explaining how we should approach warnings of mass tragedy, then I'm happy to ignore unnecessary divisions between existential threats and mass tragedies.

He gives some fine past examples of the kinds of warnings of which we should be skeptical and then hones in on a specific instance:

Over the past half century, none of our threatened eco-pocalypses have played out as predicted. Some came partly true; some were averted by action; some were wholly chimerical. This raises a question that many find discomforting: With a track record like this, why should people accept the cataclysmic claims now being made about climate change?

Here he conflates two incomparables : warnings by individuals and the popular press vs. exhaustive research by large groups of trained scientists. Here are all the examples he cites:

WhoDoes Ridley believe them?
"Millenialist priests"No
100,000 Millerites who took to the hills in 1843No
thousands who believed in Harold CampingNo
Individual scientistsNo
Wilhelm Heuper on Lung CancerNo
Best-selling economist Robert HeilbronerNo
Or best-selling ecologist Paul EhrlichNo
Rachel CarsonNo
Laurie Garrett’s 1994 book, The Coming PlagueNo
[On CJD,] A pathologistNo
William and Paul Paddock wrote in their best seller, FamineNo
Harrison Brown, a member of the National Academy of SciencesNo
Individual non-scientistsNo
Jimmy Carter in a televised speech in 1977No
bird flu, described at the time by a United Nations officialNo
Small hand-picked fact finding groupsNo
Pres. Harding's 1922 US Coal CommissionNo
Popular magazines & papersNo
Life magazine, "urban dwellers will have to wear gas masks"No
Der Spiegel, "THE FOREST DIES"No
The New York Times, "an increase in Twilight Zone-type reports"No
Movie VilliansNo
"Human beings are a disease, a cancer of this planet," says Agent Smith in the film The MatrixNo

Large Scientific BodiesYes
Cancer researchers on the "[ironclad] link between smoking and lung cancer"Yes
a 10-year ... study ... some 700 scientists on a decline of forests ... due to acid rainYes
a Finnish forestry organizationYes
So large scientific bodies who digest decades of data have a good track record in assessing risks, while individuals and media organizations have a poor track record in doing so. Now we have large scientific bodies like the National Research Council, the UK Royal Society, the American Geophysical union saying that we should be concerned about climate change. Ridley would have us believe that they are more similar to individuals and popular press outlets than the large scientific bodies that established the link between smoking and lung cancer and the groups that debunked the claim of forest decline due to acid rain.

Ridley has failed to consistently apply his own methodology to climate science, but maybe the advice he gives is better?

In the climate debate, we hear a lot from those who think disaster is inexorable if not inevitable, and a lot from those who think it is all a hoax. We hardly ever allow the moderate “lukewarmers” a voice
Ridley identifies an important question, "How should we evaluate threats so that we can respond proportionately?" and wisely rejects [unsubstantiated] conspiracy theories but then goes off the rails.

He glibly proposes splitting the middle between the two camps but gives no examples of where splitting the middle has led to better decisions and makes no effort to argue that the middle-camp has any evidence on their side.

He undermines his own argument by conflating the scientific bodies' warning about CC with individuals&press who are poor signals instead of comparing them to the scientific bodies that he cites in favor of skepticism. He then fails to argue for skepticism instead invoking the fallacy of the middle ground.

Luckily Ridley's own examples re acid rain and smoking suggest a better strategy: critically examine the available evidence. He should have instead said

Most of these warnings about the end of the world are bunk but some aren't and we have to figure out how to respond proportionately to threats despite a cloud of overblown rhetoric. Don't listen to politicians and don't trust the popular press to give an accurate accounting of science. It's time to listen when there's a widespread scientific consensus based on a significant body of data. Oh, and you should support science funding so that scientists can reach consensus on emerging threats more quickly.