Is global warming just symbolic? Like so many other theories, it seems forever tentative.

Deseret News, Tuesday, November 05, 2002

Iceberg theories melting

By Jesse Hyde
Deseret News staff writer

PROVO In March 2000, the largest iceberg ever observed broke off an ice shelf in Antarctica, signaling for many a warming of the planet.


A pair of scientists concluded a year later that the number of icebergs around Antarctica was on the rise. The icebergs were melting, it seemed, because the planet was getting hotter.


A recent study by a Brigham Young University professor disputes this theory. David Long, a BYU professor of electrical engineering, says the increasing number of icebergs observed around Antarctica has nothing to do with global warming.


"There's no evidence that there's a connection," Long says. "Basically, we see better now, so we see more."


Long and his students spent more than a year studying 20 years of satellite pictures and radar images taken of the waters around the South Pole and determined the number of icebergs near Antarctica has not changed substantially. More icebergs are reported today because the tools to spot them have improved, the study found.


Researchers have used satellite imaging to identify and monitor icebergs since the early 1970s, but cloudy weather and dark nights often prevented some icebergs from being photographed and identified.


Scientists then began using radar, which can identify icebergs through clouds and operate at night. Until recently the resolution of the radar images was too low to detect icebergs smaller than 35 miles across.


Long's research team created a computer program that produces images sharp enough to spot icebergs as small as a mile wide.


The number of icebergs found in Antarctica has not changed much since 1978, Long concluded. The massive icebergs recently observed breaking off ice shelves are the result of periodic growth and retraction of the large glaciers that yield icebergs every 40 to 50 years.


"This is not evidence of global warming," Long said. "But it also does not say global warming isn't occurring. It doesn't say anything either way."


In fact, Long has done other research that supports the global warming theory. He found more melting of snow on the Greenland icecap is the result of a one degree temperature increase that is consistent with other global warming theories.


Douglas MacAyeal, a University of Chicago glaciologist who tracks icebergs, applauds Long's research and says linking iceberg growth to global warming would be premature.


"Any reputable scientist would not disagree with what I've said," Long said.


Long's study was published in EOS Transactions, a publication of the American Geophysics Union. Cheryl Bertoia, of the U.S. National Ice Center participated in the study.




Jim Cobabe
[EMAIL PROTECTED]
http://members.tripod.com/~jcobabe

When I use a word, it means just what I choose it to mean--neither more nor less.






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