Scientists are debating whether the existence of the huge icebergs is due to a general warming of the climate in Antarctica or simply part of some other natural process in which pieces of ice break away--or "calve"--from the Ross and other ice shelves in the same way that human fingernails break off when they reach a certain length.

But Emslie noted, paradoxically, even if the calving is due to warming, because the icebergs are causing a concentration of sea ice that could eventually cause an abandonment of penguin colonies, scientists in the future could interpret the abandonment as evidence of a cooling trend.

"I think it's a good lesson for us," he said. "Although you might think this ecosystem is relatively simple, it's apparent that it's a lot more complex than it first appears."

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Contact: Peter West
pwest@nsf.gov
703-292-7761
National Science Foundation
8-Dec-2003