NCPA - National Center for Policy Analysis

Antarctic Ice Sends Mixed Warming/Cooling Signals

April 2, 2002

Both proponents and opponents of global warming theories cite weather trends in the Antarctic to bolster their respective cases. But some scientists are reminding them that the Antarctic is a huge continent, and -- as with all continents -- weather variations are to be expected.

  • Antarctica covers 5.4 million square miles -- one-third larger than the United States.
  • Just as the U.S. Midwest may experience a heat wave while the Northeast is unusually cool, climate does not move in lockstep across Antarctica.
  • Climatologists rely on ice data to form their theories -- which is not surprising since 90 percent of the world's ice lies either on the continent or on sheets that have flowed offshore to form floating platforms.
  • While recent reports of the disintegration of an ice shelf the size of Rhode Island sparked fears of rising sea levels and flooding of coastal areas around the world, scientists say that will not happen.

In the first place, melting ice shelves would not raise the levels of oceans. Also, annual temperatures in the Antarctic interior average minus 70 degrees Fahrenheit or colder. Even a 10 degree temperature rise -- greater than climate models' worst-case predictions -- would leave almost all of the ice frozen.

Changes in the Antarctic landscape do not have a single cause, scientists assert. Causes might include natural cycles of the continent; delayed effects of the end of the last ice age; or the warming trend of the last century -- which is not necessarily a sign of human-induced global warming, scientists caution.

Source: Kenneth Chang, "The Melting (Freezing) of Antarctica," New York Times, April 2, 2002.


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