Iceberg recount clears global warming of blame

Increased numbers of large icebergs off Antarctica’s coast are not necessarily due to global warming, according to US research. A reanalysis of the area and of previous findings along Antarctica’s coast shows the number of icebergs have remained the same from 1978 to the 1990s.

David Long, electrical engineering professor at Bingham Young University, and Cheryl Bertoia of the U. S. National Ice Centre say that global warming cannot be attributed to iceberg behaviour because previous analyses of icebergs were incorrect. In fact there has been no dramatic change.

In the study, published in the latest issue of EOS Transactions, Long used computers to enhance the images taken from the Antarctica region transmitted by satellite. Comparing his findings with records from the federal government’s National Ice Centre, he found a huge undercount by the NIC.

“Dr. Long’s analysis shows that the increase is only an apparent increase, and that it is premature to think of any connection between this kind of iceberg (growth) and global warming,” said Douglas MacAyeal, a University of Chicago glaciologist who tracks icebergs.

Long and his assistants have developed a better use of images generated from the NASA SeaWinds-on-QuikSCAT (scatterometer) satellite for tracking icebergs. Until recently, the resolution of the images generated by the ‘scatterometer’ was too low to distinguish icebergs. Long’s team developed a computer processing technique that produces images sharp enough to reliably track icebergs.

“His research, particularly that with his amazing ability to detect and track icebergs, is really the best method for determining the actual rate of the creation of icebergs, ” added MacAyeal.

Long does however distinguish between his findings and the reasons for the Larsen B incident, which he says, was a result of localised warming (see related story).

However Long does not attempt to refute global warming through his research. “Global warming is real,” he said. “The issues are: is this strictly man-made or is it part of normal cycles? There is evidence to support both sides on that one.”

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