Tuesday, March 9, 2010

Poles Apart

Over the past few months, scientists studying global warming have been rocked by a series of awkward revelations. In November, someone made public more than 1000 emails, many quite damning, from climate researchers at the University of East Anglia (UEA), in what skeptics successfully branded as "Climategate." December and January saw the authoritative Intergovernmental Panel on Climate Change (IPCC) admitting that their published claim that Himalayan Glaciers would disappear by 2035 was improperly sourced and wrong, even as critics pounced on other instances in which the panel violated their own procedures for insuring that science was properly represented in their influential reports. (The IPCC had shared the 2007 Nobel Peace Prize with Al Gore.)

Not surprisingly, different people responded completely differently to these events. Critics see the revelations as confirming that global warming, and especially its human source, is just a hoax. Others counter that the revelations that scientists are fallible human beings do not in the least affect the overwhelming evidence for man-made climate change. Unsurprisingly, both extremes find confirmation for what they already believed.

They are also both wrong.

First let's examine the hoax theory. Although we don't know who released the emails, they look to have been culled from more than a decade of exchanges and chosen to best incriminate the mainstream climate researchers, both those at UEA and their correspondents. What is striking is that the emails do not
reveal any serious evidence that the researchers are fabricating the global temperature rise.

To be sure, the emails show serious misbehavior, including a request from UEA researcher Phil Jones that others delete emails to avoid a freedom-of-information inquiry. Other emails suggest that the researchers hoped to tweak the IPCC process to exclude legitimate, peer-reviewed papers that they didn't regard as credible.

But if the emails showed evidence of a true hoax, the critics poring over them haven't found it--and not for lack of trying. Instead, they have highlighted examples of ambiguous or unfortunate wording, which are conveniently picked up by the likes of Sarah Palin. But although Palin may not know any better, the critics understand that when Jones referred in 1999 to Penn State researcher Michael Mann's "trick" to "hide the decline," he was describing a technique to de-emphasize the inconvenient truth that tree-ring data don't match measured temperatures, which were clearly rising.

This is a serious matter: if the tree-ring data are not good proxies for temperature in cases where we know the temperature, how can we trust them in cases where we don't know the temperature? But as far as I know, the published papers acknowledge this manipulation, which is an acceptable way to deal with omissions of questionable data. Nothing is being hidden. In fact, this whole issue was addressed by the U.S. National Academy of Sciences in 1996, who confirmed the unprecedented nature of the current warming trend.

The critics know this. Their use of this and similar examples shows that they are less interested in the overall truth than in scoring points and discrediting mainstream climate science.

But the disingenuous actions of the critics do not excuse the behavior of the mainstream scientists.

It is tricky to interpret what must have been seen as private correspondence between colleagues. Nonetheless, the emails seem to show that the East Anglia scientists did not really trust the processes of science, or at least the political decisions based on the science. The researchers in the emails are acutely aware of the political context of their results, and present the data to make their case. For example, UEA tree-ring expert Keith Briffa says "I know there is pressure to present a nice tidy story as regards 'apparent unprecedented warming in a thousand years or more in the proxy data' but in reality the situation is not quite so simple." Briffa, whose data contains the "decline," commendably goes on to argue for a more honest and nuanced description of the data.

It's not unusual for researchers to choose data to tell a particular story. And there really is no evidence that the researchers suspected the story they were telling--of unprecedented, industrially-caused warming--was wrong. But it is clear that the handful of teams around the world who evaluate historical climate trends displayed their data to support a clear end goal. Subsequent revelations show that this mindset also affected the choice of references in the IPCC report, especially with regard to the impacts of climate changes.

One of my correspondents, a biologist who uses complex biological models, likens the climate-science consensus to Lysenkoism--the Soviet era anti-Darwinist biological agenda. I take this person to mean that dissent from the reigning paradigm is not accepted in mainstream scientific circles: anyone questioning the "consensus" is quickly branded a "denier." This is not the way to do science, especially for something as important as climate change. And what it means is that the "overwhelming consensus" is not as convincing as it seemed a few months ago.

But it doesn't mean that the consensus is wrong.


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