Geology Home Page physical geology historical geology planetary gems
Roger Weller, geology instructor
by Scilla Burton
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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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.
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.
Photographer: Arthur Rothstein
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”).
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.
Photographer: Mike Olbinski
Haboob storm in Phoenix, Arizona
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.