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on 16 April 2013

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Transcript of Glaciers

Glaciers 1. Percentage of Freshwater on Earth Glaciers represent 75% of the freshwater on Earth. [1.b] 2. Locations of Glaciers in the World Most glaciers are found on or near the north and south poles. However, glaciers exist on every continent and cover about 10% of the land on Earth. [1.a] 3. Locations of Glaciers in Canada Glaciers in Canada are located in 3 main areas: the west coast, the rockies and the Eastern Arctic. The Eastern Arctic holds the biggest and the oldest of the glaciers in Canada. This includes the Barnes Ice Cap on Baffin Island, the only fragment left of the giant Laurentide Ice Sheet that used to cover almost all of Canada. [3] 4. Glacier Formation Glaciers are formed when snow piles up in an area and slowly compresses, possibly over hundreds of years. [2.e] This process requires a lot of snowfall each year. [1.d] In addition to snowfall, glaciers require cool temperatures year round so that they maintain their size and do not calve. Calving is when chunks of ice break off at the terminus or end of the glacier. [1.a] 5. Glaciers, Ice Caps and Icefields Glaciers Ice Caps Icefields A glacier is any expanse of flowing ice and snow. [2.a] Glaciers flow downhill simply because they are so heavy. [1.c] There are different types of glaciers. [1.g] Ice caps are glaciers that cover a large area, but less than 50 000 square kilometers (that would be an ice sheet). [1.g] They are flat, high and flow outwards from the center. [1.g] [2.a] Ice caps found on the north and south poles are called polar ice caps. [1.g] Icefields are large glaciers sitting on high ground that spill over into 2 or more smaller glaciers. [2.a] They are relatively large but usually smaller than ice caps. [1.g] 6. Polar Ice Caps As the name suggests, polar ice caps are ice caps located on the poles of a planet. Just like other glaciers, polar ice caps are formed from compressed snow and ice. Polar ice caps grow extremely large since the climate near the poles is so cold. The freezing temperatures are a result of less radiation from the sun reaching the poles. The northern polar ice cap covers 9-12 million square kilometers while the southern ice cap covers about 14 million square kilometers. [4] 7. Factors the Affect the Size of Polar Ice Sheets The polar ice sheets are shrinking every year. [4] Several factors affect their size: 1. Ice caps normally shrink and grow with the change in seasons. [4]
2. The Earth goes through natural cycles of freeze and thaw. We could be in a period of warming. [4]
3. Climate change caused by human pollution could also be affecting glaciers. [4] Some scientists think that if the ice caps continue to melt at their current rate they could disappear by the year 2100. [5] 8. Factors that Affect the Size of the Columbia Icefield Like the polar ice caps, the Columbia Icefield is melting. [6] For the past 125 years, the Icefield has receded 1.5km and lost half of its volume. [6] This melting could be caused by Earth's natural cycle of melt and thaw or it could be caused by human pollution. What we do know is that the current period of melting has been short compared to past periods. [7] If the icefield disappears, there will be a drastic reduction in freshwater supply for the praries. [7] 9. Effects of Glaciers on the Land As glaciers flow, they carve and scrape the land. They also pick up and deposit material. There are many types of landforms created by glaciers. [1.h] Glaciated Valleys Valleys carved out by glaciers. [1.h] Fjords Valleys carved out by glaciers that were filled with seawater after the glacier melted. [1.h] Cirques Bowls formed when glaciers erode into a mountain. [1.h] Aretes Thin, pointed ridges formed when two cirque glaciers erode either side of a ridge. [1.h] Horns Pointed landforms formed when three or more cirque glaciers erode different sides of a hill or mountain until only a steep point is left. [1.h] Glacial Till Material picked up by glaciers and deposited when they melt. For example, gravel, dirt or rock. [1.h] Moraines Hills or ridges formed when glaciers push dirt to the side as they flow. [1.h] Kames Small hills of debris formed when streams of meltwater run to the sides of glaciers and deposit dirt. [1.h] Kettle Lakes Small lakes formed when a chunk of ice breaks off a glacier and melts to form a lake. [1.h] Erratic Boulders Large boulders picked up by glaciers and deposited far away from their source. [1.h] Drumlins Teardrop-shaped landforms that point in the direction that the glacier traveled. Scientists are unsure how they form. [1.h] Striations When meltwater flows into cracks in rock then freezes, it can split off pieces of the rock and pick them up. As the glacier flows, these bits of rock scratch the ground. These scratches are called striations. [2.c] Outwash Debris left behind by meltwater streams. [2.c] Esker A ridge left behind from sediment in streams that ran underneath the glacier. [2.c] 10. Impacts of Humans on Glaciers, Icefields and Ice Caps Since the Industrial Revolution, pollution from humans has been causing glaciers to melt at abnormal rates. [1.j] This could have many negative impacts on many species.
Tons of drinking water could be lost. For example, the city of La Paz, Bolivia uses glacial meltwater as a source of drinking water. [1.i]
Glacier water can generate hydroelectric power. Without them, many clean sources of energy could be lost. [2.d]
Many farmers might not be able to water their crops. For example, farmers in Rhone Valley, Switzerland use meltwater from glaciers as irrigation. [1.i]
Icebergs broken off from polar ice sheets could create hazards for ships. [1.k]
Scientist predict that if all the land ice on Earth melted, the seas would rise 70m everywhere. This could cause severe flooding of coastal areas. [1.b] 11. Impacts of Melting Ice on Canadian Coastlines Melting ice has many effects on Canadian coastlines:
Icebergs breaking off of weakened ice sheets are hazardous to ships. [1.k]
Coastal areas could be flooded if glaciers continue to melt. The Fraser River Delta in B.C. is one example of an area at risk. [8]
Land on the coast could be severely eroded if glaciers continue to melt. Some birds rely on coastal beaches as nesting grounds. [8]
Salt marshes that rely on a mix of salt and freshwater could be thrown off balance if sea levels continue to rise. [8]
Animals that live on northern polar ice sheets are starting to loose their habitat. For example, polar bears are loosing ice that they rely on for hunting. [8] Ways to Reduce Environmental Impact There are many easy ways to reduce your impact on the environment:
drive fuel efficient cars [5]
buy energy efficient appliances [10]
plant trees to absorb carbon dioxide [10]
recycle [10]
use rainwater to water plants [10]
fix leaky faucets and turn off water when not in use [10] Figure 0.1 Figure 1.1 Figure 2.1: Locations of glaciers in the world shown in blue. Figure 3.1: Locations of glaciers in Canada shown in purple. Figure 4.1: Diagram showing the formation of glacial ice. Figure 5.1 Figure 5.3: Iceland's ice caps. Figure 5.3: The Columbia Icefield from a helicopter. Figure 6.1: Part of the southern Polar ice cap. Figure 7.1: Melting polar ice cap. Figure 8.1 (split into 2 images): The Athabasca glacier, part of the Columbia Icefield, in 1917 and 2005. Figure 9.1 Figure 9.2 Figure 9.3 Figure 9.4 Figure 9.5: The Matterhorn in Switzerland, a famous example of a horn. Figure 9.6 Figure 9.7 Figure 9.8 Figure 9.9 Figure 9.11 Figure 9.10: An erratic boulder in Okotoks, Alberta. Figure 9.12 Figure 9.13 Figure 9.14 Figure 10.1: If glaciers continue to melt, this is what could happen. Figure 11.1: A saltwater marsh that could be at risk if glaciers continue to melt. Figure 12.1: Planting a tree, an easy way to help the environment.
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