By monitoring the change in size of glaciers around the world, scientists can learn about global climate change. One method of measuring glaciers is to send researchers onto the ice with surveying equipment. The Muir Glacier, shown here around 1950, has been studied for over 200 years. Despite typical glaciers' massive sizes, monitoring them is not always an easy task. Only specific types of small glaciers are good measures of climate change.
Some glaciers are too large to measure accurately, and others are simply too unpredictable.
Once scientists find a suitable glacier, they must take satellite images of the ice for a minimum of five years and compare the results. If a large percentage of the glacier's edge is receding then the area around the ice is growing warmer, and if a large percentage is expanding then the area is growing cooler. When enough measurements from many different parts of the world have been gathered, the researchers can determine whether the earth is growing warmer or cooler. The terminus of the Pasterze glacier, Austria. It dwarfs the three hikers at lower right.