What climategate really tells us

AL Gore and the rest of the die-hard climate campaigners are huffing and puffing that nothing in the e-mails and documents that were hacked or leaked from the Climate Research Unit in England have any bearing on what we know about climate change or the political response we should make to deal with it. The entire matter is settled science, don’t you know — nothing to see here, move along. That’s rich, coming from the same people who told us for more than a decade that findings derived from the CRU’s work constituted the “smoking gun” of human-caused climate change. Gore relied heavily on this work in his climatehorror film “An Inconvenient Truth.”

And the UN’s Intergovernmental Panel on Climate Change featured the so-called “hockey stick” — the temperature estimate of the last 1,000 years purporting to prove that the modest warming of recent decades was unprecedented and dangerous. The hockey stick was one of the pillars of the mantra that there is a rocksolid consensus of leading scientists — even though numerous critics, ultimately including the US National Academy of Sciences, noted serious deficiencies in the hockey stick.

One of the several scandalous revelations of the Climategate e-mails is that this claim of consensus is a lie. Never mind the skeptics: It turns out many of the scientists in the CRU inner circle had doubts and disagreements about their data, methodology and conclusions, and often bickered with one another about defects in their project.

One main issue of the whole “hockey stick” exercise is something called the “medieval warm period” and “little ice age” (MWP and LIA in climate-lingo). It has long been thought that the earth could have been as warm or warmer than it is now about 1,000 years ago. That’s when Greenland got its name, for example; there was a lot less ice then than there has been in recent centuries.

Both the MWP and LIA are crucial to the debate: If the earth warmed and then cooled naturally over the last millennium, then recent warming may not be unnatural or predominantly caused by man at all.

There have been rumors for years that climate campaigners wanted to make the MWP “go away,” and 10 years ago three CRU affiliated scientists (Michael Mann, Raymond Bradley and Malcolm Hughes) obliged with the release of the hockeystick graph, which claimed without doubt that the 1990s was the hottest decade in the last 1,000 years. The MWP vanished completely in their temperature reconstruction, which was based on the ingenious use of “proxies” (since there were no thermometers 1,000 years ago) such as tree rings, ice-core samples, coral reefs and lake-bed sediments.

Critics and the National Academy of Sciences ripped apart the hockey stick — but the e-mails now show us disagreements among the very scientists who produced it in the first place. Edward Cook of Columbia University, some of whose raw data Mann, Bradley and Hughes used in the hockey stick, wrote a CRU colleague: “Of course he [Bradley] and other members of the MBH [Mann, Bradley, Hughes] camp have a fundamental dislike for the very concept of the MWP, so I tend to view their evaluations as starting out from a somewhat biased perspective.” In a separate note, Cook wrote: “Can I just say that I am not in the MBH camp — if that be characterized by an unshakable ‘belief’ one way or the other, regarding the absolute magnitude of the global MWP.”

Even Bradley, one of the hockey-stick co-authors, admitted his reservations: “All of our attempts, so far, to estimate hemisphere-scale temperatures for the period around 1,000 years ago are based on far fewer data than any of us would like. None of the data sets used so far has anything like the geographical distribution that experience with recent centuries indicates we need, and no one has yet found a convincing way of validating the lower-frequency components of them against independent data . . . Therefore, I accept that everything we are doing is preliminary, and should be treated with considerable caution.”

Michael Mann, who might be called the captain of the hockey team, didn’t take these criticisms well — and lashed out at his colleagues in several heated e-mails.

There are lots more remarkable revelations in the CRU e-mail cache like this — all pointing to the disturbing politicization of the scientific community today. Maybe the most egregious e-mail of the whole packet is not CRU Director Phil Jones’s “hide the decline” post, but one where he declares: “As you know, I’m not political. If anything, I would like to see the climate change happen, so the science could be proved right, regardless of the consequences. This isn’t being political; it is being selfish.”

This may not be political, but it’s certainly unscientific. And it casts an undeserved shadow over unbiased scientists who are trying honestly to get at the truth.

Steven F. Hayward is F.K. Weyerhaeuser fellow at the American Enterprise Institute.