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Ice Caps and Sea Levels


Ice melting.

Today’s high school students were not born in 1978. This must seem like a long time ago, but yet scientists were already predicting that global warming would eventually lead to a disintegration of Earth’s polar ice caps and shelves. They also warned that the melting of the world’s ice caps would have far-reaching effects—far beyond a mere loss of ice in places where most of you will never travel.

In 1978 scientists were putting together climate models based on historical data and emerging technological advances such as new satellite data. They continued to gather data, to create new technologies, and to discover more about the complicated mechanisms of ice masses.

Since 1979, the size of the summer polar ice cap has shrunk more than 20 percent. (NASA)
New spaceborne data, research data gathered in the polar regions, and climate models indicate that the 1978 prediction might be coming true. And it might be unstoppable.

The Pine Island Glacier in West Antarctica is losing ice four times faster than it was a decade ago. Numerous ice shelves in the Antarctic and Arctic collapse and drift out to sea. The Larsen A ice shelf disintegrated in 1995; the Larsen B ice shelf disintegrated in 2002. After being stable for nearly 12,000 years, the Larsen B ice shelf disappeared in a single season.

Broken off Glacier Grey in Torres del Paine in Patagonia.

In the Arctic region temperatures are rising twice as fast as elsewhere in the world. Ice is thinning, melting, and collapsing into the sea. The largest block of ice in the Arctic, the Ward Hunt ice shelf, started to crack in 2000. Within two years it had split all the way through. The Arctic polar ice cap is contracting at a rate of 9 percent per decade. At this rate Arctic summers could be ice free by the end of this century.

The consequences of the loss of Earth’s ice sheets and shelves are far-reaching. New studies examine how the disintegration of ice sheets could result in a rise in global sea levels. Other studies attempt to estimate the level of rise should particular ice sheets disintegrate and melt in open ocean waters. Satellite images of more than 200 glaciers on the Antarctic Peninsula showed that they were melting approximately 12 percent faster in 2003 than they were in 1993.

The melting in the Arctic, for example, will affect natural ecosystems of polar bears, whales, and seals. It will change migration patterns and adversely affect the native people who depend on the ecosystem.

Without the cooling effect of the layers of ice, Earth will absorb more sunlight, and temperatures will warm even more.

A new satellite survey shows that more than 300 glaciers on the Antarctic Peninsula are flowing toward the sea some 12 percent faster in 2003 than they were in 1993.
A satellite survey shows that more than 300 glaciers on the Antarctic Peninsula are flowing toward the sea some 12 percent faster in 2003 than they were in 1993.

Increased temperatures will produce faster melting, which will contribute to sea level rise, threaten low-lying areas around the globe, cause coastal flooding, and contaminate freshwater supplies. Scientists now predict a 3-foot sea rise by 2100. This would flood approximately 22,400 square miles along the Atlantic and Gulf coasts of the United States.

“Warming Arctic Affects Wheat in Kansas.” That headline would be a lot closer to home, wouldn’t it? If Kansas becomes 4 degrees warmer in the winter without Arctic ice, which creates cold air masses that slide southward, wheat farmers wouldn’t have the needed freezing temperatures to grow winter wheat. And warmer summer days would mean 10 percent less moisture in Kansas cropland soils.

Scientists continue to measure, study, and research this complicated topic in order to better predict the changes that may be inevitable. They also look to future possibilities for remediation of the problems and important solutions to complex predicaments.