NCPA - National Center for Policy Analysis

"Natural Processes" Are Responsible For Antarctic Melting

October 13, 1999

Global warming is not -- that's NOT -- responsible for melting the West Antarctic Ice Sheet, say scientists. In a study published in the prestigious journal Science, a team of scientists led by Howard Conway of the University of Washington say the Ice Sheet may be headed for a complete meltdown in a process that started thousands of years, and there is no evidence the rate is accelerating.

  • The process "may have been predetermined when the grounding line retreat was triggered in early Holocene time," says the report -- about 10,000 years ago.
  • The grounding line -- the boundary between floating ice and ice thick enough to reach the sea floor -- has retreated about 800 miles since the last ice age, withdrawing an average of about 400 feet per year for the last 7,600 years.
  • "It seems like the rate [of melting] that has been going on since the early Holocene is similar to the rate right now," says Conway. "Collapse appears to be part of an ongoing natural cycle, probably caused by [a] rising sea level initiated by the melting of the Northern Hemisphere ice sheets at the end of the last ice age."
  • Continued shrinking, perhaps even complete disintegration, "could well be inevitable," the report concludes.

According to estimates, the ice sheet's complete melting could raise the global sea level by 15 feet to 20 feet. But at the current rate of melting, which is raising sea levels about 0.04 inches annually, that would take about 7,000 years.

Source: Associated Press, "Melting of Antarctic Ice Sheet Is Linked to Ancient History," New York Times, October 12, 1999.


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