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updated: 2/8/2011 9:42 AM

Global warming is altering Antarctic

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  • Antarctica is a series of islands covered by ice. Think of it as a frozen Hawaii with penguins.

      Antarctica is a series of islands covered by ice. Think of it as a frozen Hawaii with penguins.
    Courtesy National Science Foundation

 

Students in Elise Diaz's fifth-grade class at O'Plaine School in Gurnee want to know: "Will Antarctica completely melt because of global warming?"

Scientists agree that human actions have caused changes in the earth's natural greenhouse, the process in which heat radiates from the earth to space.

Increases in greenhouses gas emissions -- carbon dioxide, methane and nitrous oxide -- have made the earth warmer. Warmer temperatures have melted ice in Antarctica.

What's causing the increase in greenhouse gasses? The two biggest problems are the use of fossil fuels, which are burned to create energy and fuel, and deforestation.

"There is no simple answer to this question because we don't know just how much warmer Earth will get and how long the warming will go on. The answers depend, in part, on decisions people make about burning fossil fuels," said Christina Hulbe, glaciologist and associate professor of geology at Portland State University.

The Antarctic ice sheet is losing mass and the ice is disappearing at a faster rate than it was 10 years ago. Measurements taken from NASA satellites have shown that marine glaciers in West Antarctica have been retreating since the 1990s, and the ice melt is now contributing about half a millimeter (a fraction of an inch) each year to sea levels. Some of that change is due to warming ocean temperatures near the ice.

"Thinking just over the next hundred years or so, Antarctic ice will continue to change in response to global warming, but it won't disappear," Hulbe said. "We don't know how long those changes will go on, but glaciologists like me are busy using computer models to try to figure it out."

Melting all of the ice in Antarctica and Greenland would cause sea levels to rise about 230 feet, but that's not going to happen anytime soon.

"The best estimate I've seen in the scientific literature suggests that ice sheets could add somewhere between 80 centimeters (about 2 feet) and 2 meters (about 6 feet) to global sea levels over the next 100 years," Hulbe said.

"It is harder to make projections over longer time scales, thousands of years, because we need to consider many different interactions among parts of the Earth system."

Being a kid doesn't mean you can't help slow the global warming process. Go green and participate in Earth Day events. Join kids around the world who are also concerned about the Earth's future.

Learn more at the United Nations Unite for Climate website, uniteforclimate.org.

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