Image 11 |
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| Icebergs off the Adelie coast (South Pole) These drifting icebergs recently detached from the glacial platforms of Antarctica, as can be seen from their flat shape and the ice strata that are still visible on their jagged sides. Like all 480 cubic miles (2,000 kilometers cubed) of ice that detach every year from Antarctica, these icebergs will slowly be eroded by the winds and waves before disappearing. Antarctica is a place of extremes: temperatures reach as low as -94°F (-70°), and winds reach speeds of 200 miles (300km) an hour. The continent has an area of 5,500 square miles (14 million kilometers squared) and contains 90 percent of the ice 70 percent of the freshwater reserves of the planet. Antarctica has been governed since 1959 by the Washington Treaty, which gives it international status and restricts its uses to scientific activities. The Russian station at Vostok has extracted, from a depth of 11,800 feet (3,623 m), chunks of the ice that have made possible the reconstruction of more than 420,000 years of history of the climate and atmospheric composition. The atmosphere's current content of carbon dioxide-the main gas responsible for global warming-is higher than it has been for 160,000 years. |
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