Tuesday, June 20, 2006

The Meaning of Ice

A comment left here suggests that An Inconvenient Truth "conveniently ignore[s] important data that don't fit with their desired conclusions." In support of this point, the commenter cites a study by Curt Davis, published in the journal Science, that indicates that the East Antarctic ice sheet increased in size from 1992 to 2003. This press release from the University of Missouri suggests that the commenter, like an oil-industry try-not-to-think tank that has recently aired misleading television ads, misrepresented Davis's research. (I include the press release in its entirety.)

COLUMBIA, Mo. - Recently, the Competitive Enterprise Institute (CEI), a non-profit public policy organization based in Washington, D.C. and partially funded by large oil companies, announced a national television campaign claiming that global warming is not causing ice sheets to shrink. Curt Davis, director of the Center for Geospatial Intelligence at the University of Missouri-Columbia, says CEI is misrepresenting his previous research to back their claims.

"These television ads are a deliberate effort to confuse and mislead the public about the global warming debate," Davis said. "They are selectively using only parts of my previous research to support their claims. They are not telling the entire story to the public."

"The text of the CEI ad misrepresents the conclusions of the two cited Science papers and our current state of knowledge by selective referencing,"said Dr. Brooks Hanson, deputy editor, physical sciences, Science.

Prior to Davis' 2005 Science study, the U.N. Intergovernmental Panel on Climate Change said that if global warming were occurring, increased recipitation in Antarctica's interior would likely result. In his study, Davis reported growth in interior East Antarctica. He said this growth was probably caused by an increase in precipitation.

Davis said that three points in his study unequivocally demonstrate the misleading aspect of the CEI ads.

- His study only reported growth for the East Antarctic ice sheet, not the entire Antarctic ice sheet.

- Growth of the ice sheet was only noted on the interior of the ice sheet and did not include coastal areas. Coastal areas are known to be losing mass, and these losses could offset or even outweigh the gains in the interior areas.

- The fact that the interior ice sheet is growing is a predicted consequence of global climate warming.

"It has been predicted that global warming might increase the growth of the interior ice sheet due to increased precipitation," Davis said. "All three of these points were noted in our study and ignored by CEI in a deliberate effort to confuse and mislead the public."

It is worth noting (and I'll gladly take the opportunity to do so) that I should have avoided the term "global warming" in this post. The better term--because anthropogenic effects on climate are expected to produce some areas of local cooling within an overall environment of warming--is "climate change." For example, a collapse of the thermohaline conveyor--a possibility examined in a 2003 Department of Defense (Office of Net Assessment) study entitled An Abrupt Climate Change Scenario and Its Implications for United States National Security (available all over the Internet), would turn London into a decidedly frigid destination, not the tropical vacation spot envisioned in the USA Today series I mentioned yesterday.