Clarification.

My article "Scare of the Century" (June 5) quoted University of Virginia climate scientist Patrick J. Michaels as saying that "Antarctica has been gaining ice," and, based on Michaels's view, called 2002 a "high-water mark for Antarctic ice." Michaels cited a study by Curt Davis to support his position. Davis subsequently noted that his study did not measure ice changes over all of Antarctica. It showed that a large part of the East Antarctic ice sheet was growing while much of the West Antarctic ice sheet was shrinking. Davis wrote in his study that, if the observed growth pattern held for all of East Antarctica, it would outweigh estimated ice loss in West Antarctica; but he did not conclusively prove this to be the case. The argument in "Scare of the Century," however, did not depend on Davis's study; in fact, it noted that research subsequent to Davis's shows a current net ice loss for Antarctica. Regardless of whether Antarctica was gaining ice between 1992 and 2003, all of the following are true: 1) Measures of Antarctica's total ice mass exist only for the last three years, a period too short to prove the existence of a climate trend; 2) natural phenomena can be invoked to explain a significant portion of observed ice-cap melting; 3) the evidence does not establish that sea levels will rise to a dangerous level in the foreseeable future; and 4) CO2 caps along the lines of the Kyoto Protocol would have a negligible effect on climate.

Jason Lee Steorts