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Earth's Melting Ice

Rising temperatures in Alaska have led to the regression of many glaciers. One great example is Spencer Glacier in Chugach National Forest, where an average rise in temperature of only four degrees in the past 50 years has caused the glacier to lose nearly 12 inches of surface ice every day and about 100 feet off the face yearly. Alaska and Spencer Glacier are not unique. This is an important issue because glaciers and ice caps hold 68.7 percent of Earth's total freshwater, and if all land ice melted, sea level would rise by 70 meters. Impacts would be significant worldwide.


Glaciers are formed when snowfall accumulates due to year-round low temperatures. Then, as more and more snow accumulates, it becomes ice. As the ice builds up, pressure increases causing movement downward until it becomes a frozen river or glacier. As the glacier's weight causes it to slide down a mountain, more snow falls at the top of the glacier, making it appear like a long, frozen river. In the summer, when temperatures are higher, some of the ice melts leading to flowing water under the glacier, making it slide or move faster. Because glaciers are on large slopes they can slide easily as its own weight causes it to creep downward. As the glacier continues to slide, friction on the solid bedrock causes crevices and caves to form in the glacier and erosion on the rock below. This is becoming increasingly prevalent as glaciers melt away and reveal large valleys of bare rock. Other important ice formations on planet earth include icebergs, ice caps, ice fields, and the large Greenland and Antarctic ice sheets.


As climate change continues, glaciers are melting faster and faster. We need to understand how they are melting as it gives us important information on how climate change is continuing. Glaciers can also tell us about climate patterns from the past. Scientists can extract ice cores from deep in the glacier and look at trapped air bubbles to tell us about the air composition from thousands of years ago. More specifically, scientists can compare current and past amounts of carbon dioxide and methane in the air and use the ratio of heavy and light oxygen isotopes to determine ancient temperatures. Satellite imagery can be used to track the growth, decay, and movement of glaciers. A more advanced version of satellite imagery called satellite radar altimetry mapping and change detection gives quantitative data on the size and movement of glaciers. There is also a new tool being used that is small enough to fit in a backpack so it is easier to carry to remote glaciers. It is designed to measure optical properties and the composition of the ice.


Glaciers are very important for the health of the earth and the negative impacts of glacial melt are noteworthy, with the most obvious being sea level rise. Remote villages in Alaska have already had to relocate. If glaciers continue to melt, places like Florida, Hawaii, and New York will be underwater. Glacial melt also disrupts oceanic currents due to an increase of cold water at the poles. This can lead to disrupted weather cycles and more extreme weather events. Ice melt can also cause the death of species due to a lack of natural habitat (e.g. polar bears) and increased glacial sediment in water. In addition, glaciers demonstrate very high albedo (light reflection on earth’s surface). Albedo rises when glaciers melt, causing even higher temperatures on Earth.

Many people are surprised to learn that we are currently in the Quaternary Ice Age that began 2.5 million years ago. While there are expected periods of cooling and warming, or glacial and interglacial periods, the earth is warming at an alarming rate. The ten warmest years in recorded history have all been in the past decade. This will continue to have increasing negative impacts on earth. Studying the glaciers, or giant rivers of ice, is more important than ever to learn about the climate from the past, to predict climate change in the future, and to help develop a plan to combat global warming.


About the Author

Tyler is interested in studying environmental and conservation sciences in college. He enjoys going out of his way to learn about wildlife.

 

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