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Roger Weller, geology instructor

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glaciers
by Scilla Burton
Physical Geology
Fall 2013
                  

  

Glaciers and the Effect on Weather
 

            Glaciers have been part of our planet’s geography for millions of years. They are formed during ice ages and recede or vanish during periods of warmer weather. A glacier is a massive sheet or river of ice that moves along with help from the forces of friction and gravity. Almost all the glaciers currently on our planet occur at the poles, which means that most people will  not have the opportunity to ever see one, making them all the more interesting to learn about. Glaciers are an invaluable tool for climate scientists, because they are so old that a core sample taken from a glacier can offer information about the climate from far earlier in our Earth’s history. Future climate patterns may also be predicted from studying glacial ice. There are many unique features that categorize glaciers and the surrounding land, like arętes, ogives, and plucking. Certain weather patterns can also be attributed to glaciers, as you will see.
 

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Copyright © 2012 • discover-world

Cave inside of a glacier
 

            Glaciers are often so massive that their passing over an area greatly affects the soil composition. The grinding and pressure of the moving ice mass causes the rocks to break down in many different ways. This process can take hundreds or thousands of years (“Glaciers Affect Land”). Glacial till is a mixture of particles of various shapes and sizes, from boulders to grains of sand. It is picked up by the glacier and then further broken down. The finest material that is created by this erosive process is known as rock flour. When they melt during warmer periods, they create lakes, rivers and streams that can also greatly change the surrounding landscape. In Glacier National Park in Montana, there are 131 lakes, and most of them are caused by meltwater. The park also boasts 1,557 miles of perennial streams inside of the park boundaries. And that is just from the glaciers in one national park (“Rivers”). Glaciers alter the soil all over the world, on every continent.
 

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Photographer: Peter Jacobson

Glacial till in New England
 

            The Dust Bowl has been called the worst natural disaster in United States history. Due to overfarming and overgrazing, the soil in the Midwestern United States quickly became depleted. When the winds came, they picked up a huge amount of dust, which nearly buried whole farms and made previously productive farmland almost uninhabitable (“Erosion”). The economy of the 1930’s when the Dust Bowl occurred was already struggling, and this disaster made it even worse. During the last Ice Age, most of North America was covered by huge glaciers. When the glaciers in the Rocky Mountains melted, they released soil which was washed down to the Great Plains. Some of this soil wasn’t ideal for farming one of the most popular crops, which was wheat. However, farmers attempted to grow it there anyway. In the following years, the combination of intense farming and periods of drought destroyed the fertile soil. Previously, the soil had a unique characteristic called flocculation, which made it stick together and become slightly denser. Farming the land broke down the soil so that flocculation no longer occurred. The dirt and sand particles became looser and lighter, and the wind was able to pick them up. The farmers and their families were constantly assailed by dust storms, making it difficult to go outside, let alone manage a large farm. As a result, many migrated to California to find a better life (“Dust Bowl”). The Dust Bowl is one of the best examples of how glaciers can affect the weather, and even change the course of history. If the water from the retreating glaciers hadn’t washed fertile soil into the Midwest, the Dust Bowl phenomenon might not have ever occurred.
 

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Photographer: Arthur Rothstein

Dustbowl family
 

            Dust storms still occur frequently on our planet, and in fact have increased in recent years. This is a cause of alarm for the scientists who see a connection between current glacial melting and the simultaneous spike in dust storms. Joseph Prospero is an atmospheric chemist working at the University of Miami. He and his team of scientists have been  conducting the largest study so far on dust storm patterns across the globe. Through his data, Prospero sees evidence that spikes in dust storms can be traced back to increased melting at the poles and other places. According to Daniel Muhs, who is working with the U.S. Geological Survey in Denver, the retreating ice reveals the fine rock dust underneath, which gets into the air. Scientists already knew that the soil in many parts of the globe was made by glacial movement. He can also see that in Earth’s past, high levels of atmospheric dust corresponded to warmer weather.  The impact of dust storms may have a negative effect on human health as well, says Prospero. At times, the dust can be so fine that people breathe it in and swallow it without realizing. While he doesn’t know what the ingestion of the airborne dust might do to a person, he does observe that hospital visits for respiratory illnesses see an increase when there are more dust storms. Additionally, scientists worry that breathing in fungus spores or bacteria along with the dust will increase certain diseases (“Retreating”).
 

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Photographer: Hermanhi

Melting Arctic Ice
 

Haboobs and dust devils are phenomena caused by too much dust in the air. According to Bing Dictionary, a haboob is “wind blowing desert sand: a violent sandstorm or dust storm that sweeps across the deserts of northern Africa and Arabia and the plains of South Asia.” Haboobs also occur in Arizona (“Haboobs”). From a distance, haboobs look like a dark, inpenetrable and unstoppable cloud of dust rolling across the desert plains. It is a terrifying sight to anyone who doesn’t know what it is, and has even been called “apocalyptic” by Phoenix area newspapers. Dust devils are caused by the circulation of sand particles in the air, but typically dissipate after a few minutes. This is different than haboobs that can last for a couple of hours (“Haboobs”). If global warming and glacial melting continues at the rate it’s going now, we can expect to see more haboobs and related phenomena in the future. Overgrazing and destructive farming practices can also change the soil that the glaciers leave behind, and cause more destruction. The world’s remaining glaciers are at risk. It is up to us to change the way we treat the environment, before it’s too late.
 

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Photographer: Mike Olbinski

Haboob storm in Phoenix, Arizona
 

Works Cited

Hedding, Judy. "Haboobs in Phoenix." About.com Phoenix. About.com, 2013. Web. 24 Nov. 2013.

"How Do Glaciers Affect Land?" National Snow and Ice Data Center. NSIDC, 2013. Web. 24 Nov. 2013.

"Rivers and Streams." National Parks Service. National Parks Service, 25 Oct. 2013. Web. 24 Nov. 2013.

Sander, Noel. "American Dust Bowl." American Dust Bowl. ICE Case Studies, 7 May 2013. Web. 24 Nov. 2013.

Da Silva, Wilson. "Retreating Glaciers May Boost Dust Storms." COSMOS Magazine. Cosmos, 2013. Web. 24 Nov. 2013.

"What Causes Erosion?" WiseGEEK. Conjecture Corporation, 2013. Web. 24 Nov. 2013.