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     FancyEnglish        Cracks in the Ice         课件首页

        March 27, 2008

(CNN Student News) -- March 27, 2008 Cracks in the Ice - Travel to Antarctica to check out the continent's latest icy breakup. CARL AZUZ, CNN STUDENT NEWS ANCHOR: Hi, I'm Carl Azuz. However you are watching this edition of CNN Student News, we're glad you are. Thanks for tuning in this Thursday. First Up: Cracks in the Ice AZUZ: First up, we're heading south to Antarctica, where it's cold, but apparently not cold enough. A huge chunk of ice broke away from the continent this week, and some scientists are blaming it on the changing climate. Now, since Antarctica is south of the equator, summer just ended down there. So, this is the time when major events like this are most likely to happen. Emily Chang has more details now on the icy breakup. (BEGIN VIDEO CLIP) EMILY CHANG, CNN REPORTER: Scientists fly over a giant chunk of Antarctic ice as it cracks and collapses. The chunk is enormous, about 7 times the size of Manhattan, 160 square miles. It was part of the Wilkins ice shelf, the biggest on Antarctica yet, scientists say, to fall victim to global warming. DAVID VAUGHN, BRITISH ANTARCTIC SURVEY: Watching Wilkins ice shelf disappear at the moment, we learn a lot more about how ice responds to climate change. CHANG: The ice is just a small fraction of the Antarctic ice sheet, but it broke off well before scientists predicted, a sign they say that climate change might be happening faster than expected. One expert told us last year... LONNIE THOMPSON, GLACIOLOGIST: I think what we do know is that ice is probably the best sensor of these large scale changes taking place. And in many ways, I think we're in uncharted territory. CHANG: Ice plays a vital role in cooling the Earth's temperature and regulating sea levels. As it's lost, the planet gets warmer, sea levels rise and more ice is threatened; a vicious environmental circle. By the end of the century, many experts project sea levels will rise between 7 and 23 inches, and temperatures could increase by up to 7 degrees Fahrenheit. But some say those estimates are too conservative. JAMES HANSEN, NASA CLIMATE SCIENTIST: There are glaciologists now who are getting very worried. But they haven't really come out and said what they think. CHANG: This part of the Antarctic is warming about five times faster than the rest of the world. Six other ice shelves have been lost entirely, and scientists say the Wilkins shelf could be next. Emily Chang, CNN, London. (END VIDEO CLIP) Fact Check DON LEMON, CNN REPORTER: When talking about Antarctica, you need to get at least one fact straight: It's home to the South Pole. That other ice box, the North Pole, is found in the Arctic. Another difference: Antarctica is a continent surrounded by ocean. The arctic is an ocean surrounded by continents. Think superlatives when considering Antarctica. It's the coldest continent, with the Earth's lowest ever temperature of minus 128 degrees Fahrenheit recorded there. Antarctica is also the windiest and driest continent, averaging less than 0.157 inches of precipitation a month; about the same as the Sahara desert. It's also the highest, averaging about 7,500 feet above sea level. Among the seven continents, Antarctica is the fifth largest. Despite its size, Antarctica was the last continent to be discovered in the early 1800s. Seven nations now claim territory in Antarctica. Other nations, including the U.S. and Russia, don't recognize those claims and make no claims of their own, but reserve rights to do so in the future. Since the early 1960s, Antarctica has been administered under the Antarctic Treaty, with the aim of preserving it for peaceful scientific study.

    

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