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| Sunday, 3 October 2004 |
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Junior Observer |  |
| News Business Features Editorial
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Is Alaska sinking? Houses collapse. Trees fall over. Giant potholes form in the ground. Could Alaska be sinking? That's what some villagers in Alaska have been asking themselves recently-and scientists think they know why. Warmer temperatures may be causing Alaska's frozen ground to thaw. A spruce forest sinks, as permafrost supporting the forest thaws. As the ground collapses, trees topple into pools of water, causing the forest's destruction. About 85 per cent of Alaska's land surface has permafrost. Permafrost is a part of the ground that is always frozen. "In many areas of the United States, the moisture in the ground freezes during the winter," scientist Tom Osterkamp said. He has studied Alaska's permafrost for more than 25 years. "The ground that doesn't thaw during the summer is called permafrost, a combination of the words, 'permanent frost.'" Permafrost supports the ground above it-including trees, houses, and roads. If the permafrost thaws, the ground can collapse. "When big ice pieces in permafrost, which can be as large as houses, melt, the ground collapses and big holes form. Where there is a house or a road where the holes form, the house collapses too, and there are big potholes in the road," Gunter Weller of the Cooperative Institute for Arctic Research said. But why is the permafrost thawing? Some scientists say that human-caused pollution is leading to global warming. And most scientists, including Osterkamp and Weller, agree that Alaska has been getting warmer. They say that the warmer temperature is causing permafrost to thaw in some areas. The thawing permafrost can cause problems for people, plants, and animals. "The collapsing is a problem in the villages in Alaska which are built on permafrost, and some of them may have to move to safer ground, where there is no permafrost," Weller said. The Alaskan town of Glennallen saw its old post office collapse. And, according to James Walters, a permafrost expert at the University of Northern Iowa, house-moving companies have been very busy. One company's motto is "Move it or lose it," Walters said. Animals are affected by the melting too. "Melting permafrost can also destroy trees and forests," Weller said. "When holes in the ground form, trees fall into them and die. "This could turn a forest into a meadow, and animals which need the forest will have to move elsewhere." Osterkamp says that the melting could cause "severe problems." Weller agrees: "This could take hundreds of years, but in the end Alaska will look quite different from what it looks like now." Talk about a chilling theory! National Geographic Kids News
Footprints help solve dinosaur mysteries Detectives often look for footprints when they try to solve crimes. Scientists use footprints too - dinosaur footprints - when they try to figure out how dinosaurs lived and moved. Dinosaurs died out about 65 million years ago. Today scientists called paleontologists work to solve the mysteries of these ancient animals. People have discovered dinosaur footprints in many places throughout the world. Footprints, or tracks, are an important way to learn about dinosaurs. Christian Meyer of the Natural History Museum in Basel, Switzerland, calls dinosaur tracks "the closest thing to a movie" of dinosaurs. "They tell us something about the size of the animal, the way they were walking... they tell us something about their speed," Meyer said. Tracks also show that dinosaurs sometimes travelled in groups. Travelling in groups probably helped dinosaurs protect themselves from enemies. Plus, some meat-eating dinosaurs may have hunted in groups, much like wolves do today. Being in a group could help dinosaurs work together to kill large animals. Dinosaur footprints can be as small as a few inches across, but they can also be as big as a few feet across. Dinosaur footprints have been found throughout the world at over 1,500 sites, including a T. Rex footprint in New Mexico. "Trackways" are groups of footprints. Why are dinosaur tracks so important? "One animal can leave only one skeleton that can be preserved," Meyer said. But it can leave thousands of footprints and trackways. And scientists aren't the only ones finding dinosaur tracks - kids can too! Eleven-year-old Mark Turner and nine-year-old Daniel Helm discovered dinosaur tracks in British Columbia, Canada. Soon scientists began studying the tracks. Paleontologists and other people interested in studying dinosaurs are working to save the trackways from activities like construction and mining. |
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