IKONOS (1m) Satellite Image of Bear Glacier, Alaska
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(Image Credit: DigitalGlobe and Courtesy of Satellite Imaging Corporation)
Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. Studying these satellite images and climate data collected over many years reveal the signals of a changing climate.
Scientists have been able to piece together a picture of the Earth’s climate dating back decades to millions of years ago by analyzing a number of surrogate, or “proxy,” measures of climate such as ice cores, boreholes, tree rings, glacier lengths, pollen remains, and ocean sediments, and by studying changes in the Earth’s orbit around the sun.
Bear Glacier Alaska is one of the larger outlet glaciers flowing from the northeastern part of Harding Icefield toward Resurrection Bay in the Kenai Fjords National Park in the Kenai Mountains. The park is a popular area for camping, hiking, exploring, and photography.
In 1809, Bear Glacier was 26 km long and ended about 300 m from the shore of Resurrection Bay. Since that time, the terminus has gradually melted and calved icebergs, retreating 400 m before 1950 and another 1,500 m between 1950 and the mid-1990s. Substantial retreat has occurred in the last 15 years. By 2000, the terminus of Bear Glacier was actively calving large numbers of icebergs, and the small marginal lake that had developed by 1950 was quite large. By 2004, the glacier had retreated more than 2 km farther, and by 2010, about another kilometer.