Sunday, January 18, 2009

Anecdotal Reasoning on Climate Change

There's an old joke about the weather: Everyone talks about it, but no one ever does anything about it. When it comes to the climate, however, we really are doing something, and not in a good way. The distinction between weather and climate is important; treating them interchangeably confers undue importance to the transient weather while it trivializes the significance of consequential climate trends.

Many people are confused about climate change. It's not hard to understand some of the confusion because many laypeople find the numbers of climate change small or largely meaningless. How can measurements of invisible gases in parts per million have any real significance? (Too bad greenhouse gases aren't bright pink so everyone could see their accumulation.) Why should anyone care about a temperature change of a few degrees? (If it were your body you would have a fever.) Besides, wouldn't a little warming be a good thing anyway, since we'd spend less to heat our homes? (The effects go far beyond temperature; other costs will dwarf any such savings.)

The most pernicious of these "common sense" arguments against the significance of climate change draws on the unfortunate popularization of it as "global warming." People smirk, "Quite a cold snap lately, eh? Well, so much for global warming!" Otherwise intelligent people utter such nonsense perhaps because it seems innocuous--just a throw-away comment about the weather, everyone's favorite small talk subject.

Others are ideologically motivated to distort the importance of weather observations. A current favorite is claiming that 2008 "was the coldest year this century." This disingenuous phrasing is crafted to imply that 2008 was the coldest in a hundred years, rather than what it really was: the (marginally) coldest of the 8 years of the current century. The statement also avoids the deeper truth, that every year this century is on the top-10 hottest list, and 2008 was warmer than all but two years of the 20th century.

Similar foolishness, drawing climate trend conclusions from recent cold weather, was recently dashed out by the Telegraph, one the leading bastions of dotty UK wingnuttery. (The "Telegraph"? Isn't that like getting your science news from the "Buggy Whip"?)

The weather of the past few weeks would have been unexceptional in the early 1980s. Today it is being cited as definitive proof that man-made climate change can't be happening. There's a splendid example of such blithering idiocy here: Gerald Warner, writing in the Telegraph, contends that the cold snap lends more support to the idea of a new ice age than to global warming theory. Were he to apply this reasoning consistently, he would have to write another blog on Sunday showing that, due to the unseasonably warm temperatures the Met Office forecasts for the UK this weekend, global warming is definitely happening. And the following week, if there's another cold snap, he should predict a new ice age again.
To infer long term climate trends from the immediate weather is to generalize from a single instance. It's reasoning by anecdote.

There's an evident need for factual, clear and straightforward education about climate change (as distinct from the weather) to correct uninformed comment and to counteract the depressingly relentless logorrhea of deliberate misinformation from climate change deniers. Sensible information that debunks climate change myths can readily be found online here and here, as well as routinely on many excellent blogs, including Climate Progress, Gristmill, DeSmogBlog, and Real Climate, amongst numerous others. The 70% of the public that relies on TV for most of their news will need to be disabused of such lazy notions, gently but firmly, by the rest of us.

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Chris Medwell said...

When I read Michael Crichton, however, I find him sensible and reasoned as well. His main point: "Consensus" is not science. "Scientific consensus" is therefore something of an oxymoron.

CBL said...

I started writing a comment in reply, and it got rather long, so I turned it into a post instead.

Thanks for your comment, Chris, and my apologies for the delay in publishing it. My blog is configured without comment moderation (in part because I am immoderate myself) which means a submitter's comments should publish immediately. For whatever reason, however, this one was shunted into a nearly-hidden receptacle in the dashboard where I only found it, by accident, just today. Every other comment to this blog simply published directly (both before and since) so I am puzzled why this occurred.