The Hansen Effect -Updated

In 2005, NASA scientist James Hansen accused the Bush administration of trying to prevent him from expressing his views on global warming.

Speaking in the swing state of Iowa days before the presidential election, Hansen accused a senior administration official of trying to block him from discussing the dangerous effects of global warming.

In the University of Iowa speech, Hansen recounted how NASA Administrator Sean O’Keefe told him in a 2003 meeting that he shouldn’t talk “about dangerous anthropogenic interference” — humans’ influence on the atmosphere — “because we do not know enough or have enough evidence for what would constitute dangerous anthropogenic interference.”

Hansen is not an un-involved party, of course. He and Reto Ruedy published data, taken from weather stations since 1982 and earlier from ships, that indicated 1998 was the hottest year on record. In January 2006, Hansen amended that to make 2005 the hottest year on record.

In internet terms, it’s no longer news that some problems exist with his analysis. I mean, that information is four days old as I type this.

But I wanted to bring up a couple of questions. 1) How do you measure the earth’s temperature a hundred years ago to (even) half a degree precision? 2) How do you (even) define a single temperature for the entire planet so that you know what it is you’re measuring? Since the temperature varies noticeably if you move a few hundred yards, or wait a few hours (and this on top of seasonal effects) and since there are “secular” long term effects (um… changing vegetation, anyone?) all that makes a global temperature – let us say – difficult to pin down now. How do you do it before the weather station exists? (Yes, I know – proxies. And just how do you calibrate the proxies, may I ask?)

But Hansen’s problem is more basic than that. It took a team of volunteers to look at the raw data that Hansen cleaned up for publication.

One of these people is Steve McIntyre, who operates the site While inspecting historical temperature graphs, he noticed a strange discontinuity, or “jump” in many locations, all occurring around the time of January, 2000.

Y2K? Yes, that Y2K.

This error, a computer bug, got into the science because of severe lack of peer review. But wait! Isn’t peer review part of the scientific method? Um, no. It isn’t. Observe, hypothesize, predict, rinse and repeat is the scientific method. And today, finding grant money is the main pre-occupation of scientists everywhere. I mean, really. Would you spend your valuable time looking for weaknesses in someone else’s work, when it earns you opprobrium and not grant money?

That’s the problem. And it’s a big one.

Update: Update: NASAs James Hansen replies to the bruhaha (hahahaha) over corrections to “his” temperature plots.

Q1: Why does Hansen imply (rather forcefully, IMHO) that the temperatures garnered for his plot from as early as 1880 have precisions of 0.001 degrees C? Can he justify this implication? (My questions imply the statement that the temps on the far left of his graph are not reliable indicators of a the temperature increase he implies. Their error bars are much larger.)

Q2: Even assuming that his implied increase is real (which is possible, if not likely), then why would he consider this an anomaly, when older records indicate far larger increases (Europe’s ‘Little Ice Age’, anyone?). (Contrary to what poster Delmar Duncan states, it’s very likely that for the past 200 years the world has been in an unusually quiescent temperature regime. Temperatures have varied much more in the past, both up and down.)

Explore posts in the same categories: Global Warming

One Comment on “The Hansen Effect -Updated”

  1. […] Hansen Rides Again I wrote about a year ago on GSFC’s James Hansen, his public denunciation of the Bush Administration’s policy on […]

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