![]() ![]() More than 100 investigators in 24 countries are helping to build the GLIMS database. (Image courtesy of Jeffrey Kargel, USGS/NASA JPL/AGU) Click here for more information. This ASTER image shows the lakes left behind by retreating glaciers in the Bhutan-Himalaya. ![]() For the first time, scientists will be able to assess and track glacial change on a global scale through a worldwide database of glacier information. The GLIMS team uses high-resolution satellite images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument and the Landsat Enhanced Thematic Mapper Plus (ETM+), archived at the Land Processes Distributed Active Archive Center (LP DAAC), to track the size and movement of glaciers. For example, while most glaciers in Glacier National Park are retreating, some are advancing. Even glaciers within the same region can react differently to environmental changes. In addition, although a few research teams travel to a few glaciers each year to measure ice depth, size, movement, and water content, the data from individual glaciers dont necessarily reveal how other glaciers in the same regionmuch less in other parts of the worldare changing. Approximately 160,000 glaciers occupy the Earths polar regions and high mountain environments, and sending a team to each one every year would be costly and difficult to coordinate. But measuring every major glacier on Earth would be a monumental task. Scientists track glacial change by measuring individual glaciers and comparing their size over time with records of the local and regional climate. Title graphic image: South Cascade Glacier in the Washington Cascade Mountains, in 1928, 1979, and 2000 (Images courtesy of the National Snow and Ice Data Center) Glacial changes can also have a more immediate impact on communities that rely on glaciers for their water supply, or on regions susceptible to floods, avalanches, or landslides triggered by abrupt glacial melt. Tracking and comparing recent and historical changes in the worlds glaciers can help researchers understand global warming and its causes (such as natural fluctuations and human activities). Because glaciers are sensitive to the temperature and precipitation changes that accompany climate change, the rate of their growth or decline can serve as an indicator of regional and global climate change. In response to climate fluctuations, glaciers grow and shrink in length, width, and depth. Kargel is part of a research team thats developing an inventory of the worlds glaciers, combining current information on size and movement with historical data, maps, and photos. Receding and wasting glaciers are a telltale sign of global climate change, said Jeff Kargel, head of the Global Land Ice Measurements from Space (GLIMS) Coordination Center at the United States Geological Survey (USGS) in Flagstaff, Arizona. And in the Alps, glaciers are retreating and disappearing every year, much to the dismay of mountain climbers, tourist agencies, and environmental researchers. Half a world away on the African equator, Hemingways snows of Kilimanjaro are steadily melting and could completely disappear in the next 20 years. More than 110 glaciers have disappeared from Montanas Glacier National Park over the past 150 years, and researchers estimate that the parks remaining 37 glaciers may be gone in another 25 years. Visit the worlds high mountain ranges and youll probably see less ice and snow today than you would have a few decades ago. At the time of publication, it represented the best available science. This page contains archived content and is no longer being updated.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |