Threatdown: Andrew Revkin, the climate guru for the New York Times, catches me up on the rhetoric and epistemology of the tipping point in climate change.
You know tipping points – small change, bit effect. It’s a perfectly valid concept in complex systems. In the case of the climate it’s used to refer to scenarios in which an incremental increase in emissions might produce a huge change such as the total melting of the Greenland ice sheet.
Revkin informs me that there are two camps of climate scientists, and one of them believes the tipping point meme has wrongly become the centerpiece of activists’ calls for reduced emissions, when in fact we have little idea whether, when and in what ways we would tip. This group – the “others,” as opposed to the “some” – “worry that the use of the term ‘tipping point’ can be misleading and could backfire, fueling criticism of alarmism and threatening public support for reducing greenhouse gas emissions.”
Both camps agree climate change is a serious potential threat. One camp is just worried about giving the forces of climate inaction more fodder for making scientists and activists sound like a cult that keeps pushing back the date the world will end – no, for real this time.
I’m actually not in a position to judge whether activists have overused the idea. I definitely picked up some fear of a big jump in sea levels from An Inconvenient Truth – on which see Prometheus science policy blog – and from reading Elizabeth Kolbert’s Field Notes from a Catastrophe. Here are five tipping points from Nat Geo. I don’t know where they fall in Revkin’s rubric. (Side note for wonks: Where’s Roger Pielke, Jr., on all this?)
I am certainly aware of the phenomenon of finding a trick rhetorical pony and riding it into the ground. As a journalist trying to meet daily deadlines, it’s soooo much easier to rely on boilerplate than to pick through the subtleties of an issue and try to convey the bottom line precisely and accurately.
Revkin says we’re now back to the old way of thinking about climate harms, which is that, given the complexities of the system, emissions business as usual amounts to a “smooth curve” of risk – no big jumps we can be sure of. Anticipating my friend Patrick’s objections that we don’t have “credible scenarios” for climate change harms, be they gradual or sudden, I’m not in a position to provide lots of specific links.
I will say that if we have climate modeling that is deemed credible by the relevant community of experts and in which the range of possible outcomes includes those that would be hard for a lot of the world to adapt to, then to say we have to wait for perfect knowledge before we take action reminds me of the Simpsons episode where Homer lets Groundskeeper Willie take the rap for a grift he and Bart committed. Instead of fessing up, Homer lets Wille go berserk on the stand, while he keeps repeating “let’s see how this plays out” as Willie gets himself into more and more trouble on the witness stand.
Big boo yahs on working the Simpsons in to this post. +10 points for Gryffindor.