Abode of Snow

The Himalayas deserve their Sanskrit name; they are indeed an “abode of snow.” Thick blankets of white cover long stretches, making the mountain range the largest non-polar ice mass in the world. Only Antarctica and the Arctic can boast more. There are about 15,000 glaciers covering seventeen percent of the total range.

High in the mountains, a glacier forms as snow accumulates and compresses first into “firn,” a granular ice, and then finally into glacial ice. While a glacier may look static, it is always moving, albeit slowly. Pushed by its own weight, the glacier flows down the mountain, grabbing rock and debris with it. As it moves south to warmer temperatures, the foot of the glacier will slough off – giant pieces break and melt. See Graphic: Anatomy of a Glacier.

In the Himalayas, the fresh water produced by these glaciers is crucial to the river systems that exist within the mountain range. Like most things, glaciers go through cycles, periods where they tend to accrue mass and periods where they tend to lose mass. These cycles match up perfectly with river cycles. Glaciers feed rivers at higher rates before and after the monsoon season, when rivers most need additional water. Without these frozen, freshwater “storage units,” there would be a severe drop in the water levels of major rivers like the Ganges, Indus, and Brahmaputra and droughts would become common – particularly during the dryer, hotter seasons. This would be a devastating blow to the plants, animals, and more than a billion people who rely on glacier-fed, Himalayan water sources for their survival.

The Disappearing Glacier

While losing ice is a natural part of a glacier’s lifecycle, many glaciers are now sloughing off faster than they are accumulating new snowmass. In other words, they’re shrinking. This shrinking is largely attributed to climate change. Not surprisingly, rising temperatures cause glaciers to melt at faster rates. Unless snow accumulation increases at a similar rate, the glacier cannot sustain itself. Scientists have reported temperature increases above the global average at higher altitudes, where glaciers are often found. The future is not looking bright for Himalayan glaciers.

Soot: Friend or Foe?

But there’s another culprit when it comes to receding glaciers. Soot. A December 2009 study released by NASA and the Chinese Academy of Sciences found that an increase in black carbon particles and pollutants settling on glaciers actually accelerates the melting process. How? Glaciers act like mirrors. They absorb only little of the heat beating down on them, reflecting most of it back into space. By adding a layer of carbon to the ice, glaciers go from heat-reflecting landforms to heat-absorbing landforms. Unable to reflect the sun’s rays, glaciers absorb that heat, which accelerates their melting.

Could there be a bright side to soot? A January 2011 study by researchers tied to the University of California, Santa Barbara shows previously receding glaciers in the Karakoram Himalayan mountain range are now stabilizing. Over the past twenty years, glaciers in this particular region have shown a shift, with 58 percent of them either stable or growing. These glaciers may in fact be benefiting by a cover of debris. While a thin layer of debris accelerates the warming process, if the coat is thick enough, it could insulate the ice from the sun’s rays. But it’s not all good news. Despite this one somewhat optimistic finding, the report still found that 65 percent of the glaciers studied throughout the Himalayas are receding.

The two-hundred-foot walls of ice in Glacier Bay overwhelm the senses, but they also surround the most beautiful sights Alaska has to offer — the Northern Lights, the roaming grizzly bears, and the humpback whales. The glacier itself is also creating new life — it has retreated some 70 miles up the bay, wiping the ecological slate clean, allowing new plants and animals to start again from scratch. This film originally premiered November 7, 1993.

Grade Level: 9-12

Time Allotment: Two to three 45-minute class periods

Overview: We don’t often think about glaciers in our everyday lives, even though their effects are all around us. Glaciers have played a large role in shaping the world around us, from the large boulders in Central Park to the rolling hills of Ireland to Minnesota’s 10,000 lakes. For hundreds of thousands of years, the movement of glaciers has shaped land through erosion and deposition, creating landforms such as U-shaped valleys, drumlins, horns and arêtes, moraines, and kettle lakes. Currently, glacial retreat is implicated in the Earth’s changing climate patterns and may have a great impact on sea levels and weather cycles.

In this lesson, students learn how glaciers and glacial movement have affected the Earth through a series of Web interactives and hands-on activities. They learn fundamental information and terminology regarding glaciers and glaciation, and will then complete an activity using model glaciers to simulate effects on the landscape. Students then use video segments and satellite images to identify the effects of glaciation in various parts of the world. Lastly, they review current theories about cycles of climate change and relate them to glaciers and ice sheets existing today.

Subject matter: Earth Science\Glaciations\Erosion

Learning Objectives:

Students will be able to:

• Define key terms pertaining to glaciers and glaciation;
• Describe the formation process of glaciers and glacial motion;
• Explain several ways in which glaciers erode the land;
• Describe features of glacial deposition and explain how they occur;
• Recognize features of glacial erosion and deposition on landscapes;
• Explain the relationship between glaciers/ice caps and climate patterns.

STANDARDS AND CURRICULUM ALIGNMENT:

National Science Education Standards

Earth and Space Science

CONTENT STANDARD D: As a result of their activities in grades 9-12, all students should develop an understanding of

• Energy in the earth system
• Geochemical cycles
• Origin and evolution of the earth system
• Origin and evolution of the universe

Students find that the geologic record suggests that the global temperature has fluctuated within a relatively narrow range, one that has been narrow enough to enable life to survive and evolve for over three billion years. They come to understand that some of the small temperature fluctuations have produced what we perceive as dramatic effects in the earth system, such as the ice ages and the extinction of entire species. They explore the regulation of earth’s global temperature by the water and carbon cycles. Using this background, students can examine environmental changes occurring today and make predictions about future temperature fluctuations in the earth system.

Interactions among the solid earth, the oceans, the atmosphere, and organisms have resulted in the ongoing evolution of the earth system. We can observe some changes such as earthquakes and volcanic eruptions on a human time scale, but many processes such as mountain building and plate movements take place over hundreds of millions of years.

NEW YORK STATE CORE CURRICULUM ALIGNMENTS

Earth Science Core Curriculum

STANDARD 1: Students will use mathematical analysis, scientific inquiry, and engineering designs, as appropriate, to pose questions, seek answers, and develop solutions.

SCIENTIFIC INQUIRY

Key Idea 1: The central purpose of scientific inquiry is to develop explanations of natural phenomena in a continuing, creative process.

STANDARD 4: Students will understand and apply scientific concepts, principles, and theories pertaining to the physical setting and earth science recognizing the historical development of ideas in science.

Key Idea 2: Many of the phenomena that we observe on Earth involve interactions among components of air, water, and land.

Performance Indicator 2.1: Use the concepts of density and heat energy to explain observations of weather patterns, seasonal changes, and the movements of Earth’s plates.

2.1r Climate variations, structure, and characteristics of bedrock influence the development of landscape features including mountains, plateaus, plains, valleys, ridges, escarpments, and stream drainage patterns.

2.1s Weathering is the physical and chemical breakdown of rocks at or near Earth’s surface. Soils are the result of weathering and biological activity over long periods of time.

2.1t Natural agents of erosion, generally driven by gravity, remove, transport, and deposit weathered rock particles. Each agent of erosion produces distinctive changes in the material that it transports and creates characteristic surface features and landscapes. In certain erosional situations, loss of property, personal injury, and loss of life can be reduced by effective emergency preparedness.

2.1u The natural agents of erosion include:

Glaciers (moving ice): Glacial erosional processes include the formation of U-shaped valleys, parallel scratches, and grooves in bedrock. Glacial features include moraines, drumlins, kettle lakes, finger lakes, and outwash plains.

Mass Movement: Earth materials move downslope under the influence of gravity.

2.1v Patterns of deposition result from a loss of energy within the transporting system and are influenced by the size, shape, and density of the transported particles. Sediment deposits may be sorted or unsorted.

MEDIA COMPONENTS

Video:

NATURE, Ireland, selected clips:

Clip 1, “Forming the Burren”

This clip describes how glaciers eroded the bedrock of Ireland’s landscape.

Clip 2, “Glaciated Landscape”

This clip shows the many different features and effects of glaciers in Ireland.

Access the streaming and downloadable video segments for this lesson at the Video Segments Page.

Web Sites:

Our Environment: Glaciers
This interactive describes valley and continental glaciers and gives an in-depth explanation of the features of the glaciers and their effects on the landscape.

Life Cycle of a Glacier
This interactive from NOVA shows how a single snowflake makes it to the bottom of a glacier.

New York Satellite Images – Satellite Photo Map
This map contains satellite image of New York State.

Milankovitch Cycles – Interactivity – MSN Encarta
This interactive explains the three periodic variations in the Earth’s orientation toward the Sun, which are believed to cause cyclical changes in climate.

Earth science reference table for Regents exam

Materials:

For each student:

• Earth Science Reference Table – page 8
• Glacier Overview Organizer (PDF) (RTF)
• Life Cycle of a Glacier Organizer (PDF) (RTF)
• Milankovitch Cycles Organizer (PDF) (RTF)
• One model glacier
• Paper plate

For each pair/group:

• Computer with Internet access
• 5 oz. play dough (homemade or purchased)

For the class:

• Computer with Internet access, projector, and screen
• TV and DVD player
• Materials for model glaciers (to be constructed by teacher)
  • Dirt/gravel mixture (approximately 1 tablespoon per student)
  • Ice cube trays (enough for each student in the class to get one cube)
  • Water (enough to fill ice cube trays)

• Organizer Answer Keys:
  • Glacier Overview Answer Key (PDF) (RTF)
  • Life Cycle of a Glacier Answer Key (PDF) (RTF)
  • Milankovitch Cycles Answer Key (PDF) (RTF)
  • Effects of Glaciers in New York State Answer Key (PDF) (RTF)

PREP FOR TEACHERS

Prior to teaching this lesson, you will need to:

Preview all of the video clips and Web sites used in the lesson.

Download the video clips used in the lesson to your classroom computer, or prepare to watch them using your classroom’s Internet connection.

Bookmark the Web sites used in the lesson on each computer in your classroom. Using a social bookmarking tool such as del.icio.us or diigo (or an online bookmarking utility such as portaportal) will allow you to organize all the links in a central location.

Make copies of Earth Science Reference Table, page 8, for each student in your class.

Make copies of all student organizers for each student in your class.

Prepare model glaciers for students by following these steps:

1. Prepare mixture of dirt and gravel. Particles should be of different sizes. You will need approximately one tablespoon of the mixture for each student in the class.
2. Add mixture to ice cube trays. Each ice cube slot should be filled about halfway with the mixture.
3. Fill trays with water.
4. Freeze overnight.

Next: Proceed to Activities

Background:
Ireland, like much of the Northern Hemisphere, was completely covered by glaciers during the Ice Age. As the glaciers advanced and retreated over the land, they shaped and changed the surface of the landmass through the processes of erosion and sedimentation. Segments from the NATURE episode “Ireland” provide examples of the effects glaciers can have on a landscape.

Suggested Focus Questions:

Clip 1: Forming the Burren

1. How did the glaciers change the limestone outcrops?
2. How did large boulders come to rest on flat stretches of land?
3. What might the Burren look like if the glaciers covering it had been larger, and had moved at a faster pace?

Clip 2: Glaciated Landscape

1. How did frost action change the rock faces?
2. Describe Ireland’s landscape during the Ice Age.
3. What features of the landscape appear to be sculpted by glaciers? How can you tell?

Downloadable QuickTime versions of the video segments:
(Note: To download a video, right=click on the video title and click “Save Link As…’ or “Save Target As…”. On a Mac, press the CTRL key and simultaneously click the mouse, then save the link.)

Clip 1, “Forming the Burren”

Clip 2, “Glaciated Landscape“

Legend says that a magician once swam to Iceland in the form of a whale, hoping to bring the isolated North Atlantic island under his spell. But when he reached Iceland’s rocky shores, he abandoned his dream upon discovering that it was already inhabited by spirits who fiercely defended their lush green meadows, frigid ice sheets, and soaring volcanic mountains.

In Iceland: Fire and Ice, NATURE takes an inspiring look at the real spirits — both human and wild — that thrive in a challenging land where fire literally meets ice. Iceland: Fire and Ice offers a stunning portrait of this island of extremes, where some of Europe’s biggest glaciers cozy up to some of the continent’s hottest volcanic springs. And it profiles many of the remarkable animals, such as birds from the lethal gyrfalcon to the comic, clown-billed puffin, that bring vibrant life to an occasionally desolate landscape.

To Iceland’s earliest human settlers, who arrived from Europe sometime in the 9th century, the island’s ruggedly beautiful lava flows, smoking volcanic vents, and roaring waterfalls seemed inconceivably ancient. Some imagined them to be the sculpted remains of some timeless battlefield, where their immortal gods had waged a merciless war. In fact, however, Iceland is a mere child in geologic terms. It was formed by volcanic eruptions just 20 million years ago, as magma poured from the Mid-Atlantic Ridge, a tear in the seabed that marks the boundary between the North American and European continental plates. As the liquid rock oozed out of the tear and cooled, it produced the island we see today: a 300-mile-long, 200-mile-wide oval landmass that sits between Greenland and the European coast in the icy seas near the Arctic Circle.

Iceland has more than two dozen active volcanoes.

But Iceland’s construction is far from over. Today, it boasts more than two dozen active volcanoes that regularly erupt and add more lava and ash to the landscape. Indeed, Icelanders experience an eruption twice a decade on average, with the scenic Mount Hekla being one of the island’s most energetic volcanoes in recent years. While eruptions often consist of little more than a spit of smoke and a cough of ash, sometimes they can mean spectacular and dangerous geologic fireworks. In the late 18th century, for instance, Iceland’s Mount Lakagigar produced the world’s largest lava flow — more than 3 cubic miles of molten rock. Thousands of farm animals were gassed to death by the mountain’s poisonous fumes, and the eruption produced so much ash that the sky was dark for weeks. The eruption wreaked havoc on the island’s food supply, causing a famine; more than a third of Iceland’s people died.

Other memorable volcanic disasters aren’t so old. In 1973, the eruption of the Eldfell volcano threatened to entomb the nearby fishing village of Heimaey in magma. Boiling rivers of lava engulfed a third of the town before desperate islanders mounted a bold and creative defense against the mountain. Using hastily installed fire hoses and water pumps, the villagers sprayed the encroaching lava with streams of frigid seawater, forcing it to crystallize. The resulting rock dam diverted the lava rivers away from the town and into the sea. Ironically, by the time the eruption was over, the lava had formed a new spit of land that offered improved protection to the town’s harbor.

Vulcanism is not only one of Iceland’s hallmarks; it is also responsible for the island nation’s best-known contribution to other languages. The word “geyser” comes from a single celebrated spring in southwestern Iceland that every so often flings its waters, heated to boiling by the volcanic magma below, several hundred feet into the air. Today, volcanic fountains all over the world carry the name given to this Icelandic wonder, which has become less active in recent years. But many other hot springs continue to provide Icelanders with an important source of energy — and natural saunas perfect for a winter warm-up.

Volcanic fire isn’t the only elemental force shaping the island. Ice, too, plays a key role. Less than 8,000 years ago, geologists believe the entire island was buried beneath miles of ice. As these massive glaciers melted away, they carved Iceland’s remarkable steep-sided valleys and fjords, long, narrow glacial valleys that have been flooded by the sea. Today, ice continues to carve and smooth the land. About ten percent of the island is covered by glaciers. The largest, called Vatnajokull, is already more than a half-mile deep and covers about 3,000 square miles. It is Europe’s largest glacier. Indeed, all of the continent’s other ice caps would comfortably fit within Vatnajokull.

But the massive ice sheet isn’t Iceland’s only record-breaker. The island also boasts the continent’s largest and most powerful waterfall: the Gullfoss, or “Golden Falls.” Once, government planners had considered the 105-foot cascade a perfect place to build a hydroelectric dam. But folklore says a young woman threatened to throw herself over the falls if plans to destroy the natural monument went forward. Her threat worked, and today the site is protected by a national park. So, on a sunny day, the Gullfoss continues to sparkle with countless rainbows, drawing thousands of onlookers each year to view the spectacle. Like the early settlers before them, they can only marvel at the natural beauty crafted by the unlikely union of fire and ice.

To order a copy of Iceland: Fire and Ice, please visit the NATURE Shop.

Online content for Iceland: Fire and Ice was originally posted February 1999.