Geography 101: Hydrosphere and Oceans - Cryosphere Glaciers Ice Caps Permafrost

What This Is

The cryosphere is the part of the Earth's surface where water is in its solid state, including glaciers, ice caps, and permafrost. Understanding the cryosphere is crucial for grasping Earth's climate system, as changes in the cryosphere can have significant impacts on sea levels, ocean currents, and global temperatures. For instance, the rapid melting of glaciers in the Himalayas has led to increased flooding and landslides in downstream regions, affecting millions of people.

Key Processes, Landforms & Theories

• Glaciers: Large, slow-moving rivers of ice formed from compacted snow, found in polar and mountainous regions. Example: The Vatnajökull glacier in Iceland, which covers over 8% of the country's land area.
• Ice Caps: Large, flat areas of ice covering a significant portion of the land, often found in polar regions. Example: The Greenland Ice Sheet, which covers about 80% of the island.
• Permafrost: Soil and rock that remains frozen for two or more consecutive years, found in Arctic and sub-Arctic regions. Example: The permafrost in Alaska's North Slope, which stores massive amounts of carbon dioxide.
• Glacial Erosion: The process by which glaciers carve out valleys and create unique landforms. Example: The U-shaped valleys of the Swiss Alps, formed by the movement of glaciers.
• Glacial Deposition: The process by which glaciers deposit sediment, creating landforms such as moraines and drumlins. Example: The terminal moraine of the Laurentide Ice Sheet in North America, which marks the maximum extent of the ice sheet.
• Ice Sheets: Large, continuous sheets of ice that cover a significant portion of the land, often found in polar regions. Example: The Antarctic Ice Sheet, which covers about 98% of the continent.
• Firn: A layer of compacted snow that has been compressed into ice, found in glaciers and ice caps. Example: The firn layer in the Vatnajökull glacier, which is up to 100 meters thick.
• Creep: The slow movement of rocks and soil under the weight of a glacier, often resulting in the formation of unique landforms. Example: The crevasses in the glaciers of Mount Everest, which are formed by the movement of ice.
• Glacial Isostasy: The process by which the weight of a glacier causes the underlying rock to sink, resulting in the formation of a depression. Example: The depression in the center of the Scandinavian Peninsula, formed by the weight of the Fennoscandian Ice Sheet.

Step-by-Step Application

1. When reading a map, identify areas with glaciers, ice caps, or permafrost by looking for symbols or labels indicating these features.
2. When interpreting a diagram, recognize the unique landforms created by glacial erosion and deposition, such as U-shaped valleys and terminal moraines.
3. When answering an exam question, explain the formation of a glacier or ice sheet by describing the processes of glacial accumulation and ablation.
4. When calculating river discharge, consider the impact of glacial melt on the water supply and the resulting changes in river flow.

Common Misconceptions

• Misconception: Glaciers are always slow-moving and quiet.
• Correction: Glaciers can move rapidly, especially when they are flowing over steep terrain or when they are subjected to changes in climate. Example: The rapid movement of the glacier in the Khumbu Icefall on Mount Everest.
• Misconception: Permafrost is always frozen solid.
• Correction: Permafrost can thaw during the summer months, especially in areas with high temperatures or low snow cover. Example: The thawing of permafrost in the Arctic tundra, which can lead to the release of methane and other greenhouse gases.
• Misconception: Glaciers are always white and opaque.
• Correction: Glaciers can be blue or transparent, especially when they are flowing over dark-colored rocks or when they are subjected to changes in light conditions. Example: The blue color of the glaciers in the Swiss Alps, which is caused by the scattering of light by ice crystals.

Exam / Short-Answer Tips

• When answering a 4-mark question, provide a clear and concise explanation of a key concept, such as the formation of a glacier or the impact of permafrost on the environment.
• When drawing a labelled diagram, include key features such as glaciers, ice caps, and permafrost, and use arrows to indicate the direction of movement or flow.
• When answering a 6-mark question, provide a detailed explanation of a complex concept, such as the impact of climate change on the cryosphere or the formation of unique landforms through glacial erosion and deposition.
• When including place-specific detail, use examples from real-world locations, such as the Vatnajökull glacier in Iceland or the permafrost in Alaska's North Slope.

Quick Practice Scenario

A river curves sharply, cutting into the outer bank while depositing sediment on the inner bank. Name the feature and explain the process.

Answer: Meander, glacial erosion and deposition.

Explanation: The river has created a meander through the process of glacial erosion, where the glacier has carved out a U-shaped valley. The river has then deposited sediment on the inner bank, creating a unique landform.

Last-Minute Cram Sheet

• Glaciers are formed from compacted snow, not ice.
• Permafrost is soil and rock that remains frozen for two or more consecutive years.
• Ice sheets are large, continuous sheets of ice that cover a significant portion of the land.
• Firn is a layer of compacted snow that has been compressed into ice.
• Creep is the slow movement of rocks and soil under the weight of a glacier.
• Glacial isostasy is the process by which the weight of a glacier causes the underlying rock to sink.
• Glaciers can move rapidly, especially when they are flowing over steep terrain or when they are subjected to changes in climate.
• Permafrost can thaw during the summer months, especially in areas with high temperatures or low snow cover.
• Glaciers can be blue or transparent, especially when they are flowing over dark-colored rocks or when they are subjected to changes in light conditions.