Unsure about how to talk about uncertainty? Read this

2015-07-05_15-39-46Adam Corner, Stephan Lewandowsky, Mary Phillips, and Olga Roberts have today published The Uncertainty Handbook, which is a twenty-page practical guide for climate communicators. It is excellent, clearly written and I recommend that everyone read it all. Adam Corner has a blogpost outlining the Handbook at Shaping Tomorrow’s World.

As the authors say, everyone is already familiar with making decisions under uncertainty. To make plans means accepting that they may not unfold as expected. The natural world is chaotic, with many known-unknowns and unknown-unknowns. The human world is even more unpredictable. We all develop rules-of-thumb to deal with everyday uncertainty: whether to take an umbrella, when to take a vacation, whose advice to trust. But we humans do not always have good instincts when it comes to grasping the uncertainty of novel and unfamiliar situations. As Daniel Kahneman showed in his masterpiece Thinking, Fast and Slow we are often not very smart when confronting probability or logic problems in our lives, especially when they are expressed numerically.  The Economist reviewer wrote:

In one experiment described by Mr Kahneman, participants asked to imagine that they have been given £50 behave differently depending on whether they are then told they can “keep” £20 or must “lose” £30—though the outcomes are identical. He also shows that it is more threatening to say that a disease kills “1,286 in every 10,000 people”, than to say it kills “24.14% of the population”, even though the second mention is twice as deadly. Vivid language often overrides basic arithmetic.

Framing is everything.

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Consensus, Criticism, Communication

Thanks in good part to our critics, our paper Quantifying the consensus on anthropogenic global warming in the scientific literature keeps getting more attention. It almost seems that you can’t open up a browser without seeing the “97%” meme somewhere. The extra interest prompted by Richard Tol’s recent critical article has maintained the rate of downloads of the paper at 500 per day and has pushed the total to nearly 200,000. The recent buzz has also spurred discussions on And Then There’s Physics, Variable Variability, Twitter, in The Guardian and a renewed line of criticism in a series of articles by Yale University Professor Dan Kahan.

I was surprised—a little shocked even—at some reactions to the release of our consensus paper. I was prepared, of course, for an angry response from those people who maintain that the expert consensus on the basics of anthropogenic climate change is either non-existent or crumbling. But my colleagues and I were never expecting to change their minds.

However, strong and sharply-worded opposition was unexpected from people like Dan Kahan (sarcasm), Mike Hulme (“infamous”), some journalists (“unwarranted attention”) and some climate scientists (satire), none of whom actually dispute the existence of an expert consensus on the basics of anthropogenic climate change. That the criticism often seemed tinged with peevishness (at least before they did some back-tracking) was especially surprising. I never saw our work as in any way undermining their approaches and analyses, but rather complementing them. And the complaints continue.

To give you a flavour of the nature of the recent discourse, here are some Tweets. (Keywords: Haha, doesn’t work, distraction, diversion, Sad, don’t inform, They insult, psychological control):


The apparent anger and the throw-everything-at-the-wall criticism suggest that this is something other than a measured scholarly critique. Let’s first look at the main strands of argument in a bit more detail. Continue reading