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Another Round With The CRU E-mails...

A few more things to say about those hacked e-mails from the University of East Anglia. First, the latest news: It looks like the head of the university's Climate Research Unit (CRU), Phil Jones, is stepping aside temporarily while the entire matter comes under independent review. Seems fair. As I noted in my last post, some of Jones's e-mails sounded awfully unprofessional, especially the ones where he told other researchers to delete their e-mail correspondence. (They didn't, but still.) Penn State is also investigating.

Now, that said, the growing mantra among conservatives that these e-mails somehow discredit the entire body of climate science is getting overheated and absurd. Here's the New York Post complaining that, because CRU discarded one set of raw surface temperature data back in the 1980s (they still have the processed data on file, and the raw data still exists at the original weather stations, although it'd be a pain to collect again), the whole idea of man-made warming is therefore thrown into doubt.

But that second part doesn't follow. For one, CRU isn't the only group in the world tracking global temperature trends. As Michael Schlesinger, a climatologist at the University of Illinois, points out, there are at least three other groups, including NASA, NOAA, and the Japan Meteorological Agency, that have been analyzing surface temperature data for well over a century (there's a fair bit of overlap in what raw data they use, but they all have their own ways of analyzing it). Here's how they all stack up (click to enlarge):

All very similar, all showing the same clear upward trend. (If anything, note that CRU readings have been on the low side in recent years, largely because they don't include temps from the Arctic, where the Earth is warming most rapidly.) I suppose the Post could always argue that all these agencies are in cahoots, somehow coordinating fraud so as to fabricate global warming and achieve whatever dastardly ends they're trying to achieve.

Meanwhile, there have been plenty of allegations that climate scientists were engaged in statistical chicanery to manufacture the famous "hockey stick", which reconstructs global temperatures going back 1,000 years and shows that the rate of twentieth-century warming has been unprecedented. Many of the latest accusations, from what I've seen, are based on CRU e-mails quoted out of context—see here, here, or here for some rebuttals.

But set that aside for a sec: I've never understood the obsession with the hockey stick. The argument that greenhouse gases are warming the Earth doesn't even depend on it. As Potsdam oceanographer Stefan Rahmstorf explains, that case was built on a variety of attribution studies that look at recent temperature trends and sift through different possible culprits, such as CO2 or solar variations or volcanoes. What's more, if by some chance all those studies turned out to be flawed, we'd still be left with the basic fact—rooted in nineteenth-century physics—that more CO2 in the air will change the radiation balance of the earth, combined with climate-sensitivity studies that look at what previous CO2 increases have done to the Earth's equilibrium temperature. The main debate, at this point, is how strong that warming effect will be. The best historical evidence suggests it's unlikely that a doubling of atmospheric CO2 will lead to an increase of less than 2ºC, while recent observations have suggested that the IPCC may have understated the pace of warming (Arctic ice melting faster than expected, and so on).

In any case, to echo my original post, yes, climate scientists should take pains to be as transparent as possible, and some of the CRU e-mails cut against that. That needs to be remedied. Georgia Tech's Judith Curry also has a sharp take, noting that good-faith engagement with skeptics can be a positive thing. But there's no evidence that climate data has been fudged, and even if there was a smoking gun in the CRU e-mails, the basis for what we know about man-made climate change still comes from a vast array of sources—sadly, it doesn't hinge on this particular handful of scientists.* I realize the National Review editors are excited about this story and want to lash out and scream "LIAR!!!!!" but a little skepticism on their part might not be so bad.

*I say "sadly" because, frankly, I'd much prefer if global warming was fake. It's not a terribly fun issue to cover and gets a bit gloomy after awhile. Just sayin'...