An advertisement by the Exxon-funded Competitive Enterprise Institute used a study to claim that the “Antarctic ice sheet is getting thicker, not thinner” as a way of casting doubt on global warming science.
The author of the study, Curt Davis, issued a press release in response calling CEI’s ad a “deliberate effort to confuse and mislead the public about the global warming debate.” Davis noted that his finding were limited to the interior of the eastern portion of Antarctica and more snow was “a predicted consequence of global warming” as the ocean temperature warms.
In a National Review cover story, Steorts used a similar tact with Davis’s study. He used it to suggest all of Antarctica was gaining ice and cast doubt on global warming science. Nevertheless, he has repeatedly insisted that Davis’s criticism of CEI do not apply to him:
Rehashing its objection to the way I used a study by Curt Davis, Think Progress offers, for the second time, a link to a document detailing Davis’s concerns with the way the Competitive Enterprise Institute cited that study…those criticisms aren’t applicable to my article.
ThinkProgress talked to Curt Davis this morning. This is what he had to say:
When [Steorts] quoted my study he misrepresented it just like CEI did because he reported this as representative of the entire Antarctic ice sheet. I did not report a result for the entire Antarctic ice sheet. We know from other studies the coastal areas are losing lots of ice.
In his first response to our criticism, Steorts acknowledged that he falsely claimed Davis’s study applied to all of Antarctica but said it was inconsequential. Doing some calculations, Steorts asserted that even if you factor in Western Antarctica and costal regions, the continent is gaining mass.
Davis told me that Steorts “did his own math. But his math his wrong.” He assumes that ice lost on the coast has the same density as snow gained in the interior of Eastern Antarctica. Actually, ice is about three times more dense. (Even if Steorts got his math right, the data he is using for the coasts isn’t reliable enough to make such a comparison. That’s why it wasn’t included in Davis’s study.)
How much deeper a hole is Steorts going to dig himself? Only time will tell.
UPDATE: Davis writes in to more precisely describe how Steorts got his math wrong:
My study only reported the mass gain due to changes in the interior of the East Antarctic ice sheet. Steorts used the average elevation change of the entire area of study, which included large portions of East and West Antarctica, and used the density of snow to convert to mass gain for both areas. In fact, the elevation change in the West interior is, in general, due to ice loss on the coasts while elevation change in the East interior is due to snow gain. Ice is about three times more dense than snow and the appropriate way to calculate the combined effect is to use an ice density for the West losses and a snow density for the East gains.
More importantly, even if Steorts got his math right, this type of calculation cannot be used to represent the entire Antarctic ice sheet. The altimeter data used does not cover coastal regions very well, and we know from other studies there is significant ice loss on the coasts that must be considered in developing a realistic estimate for the overall contribution of the Antarctic ice sheet to sea level rise.