Climate 101: Glaciers | National Geographic

Summary

Glaciers, massive moving ice formations, have shaped Earth's landscapes for millions of years. However, climate change is causing them to rapidly disappear, altering ecosystems, oceans, and weather patterns. Glaciers fall into two categories: alpine glaciers, found in mountain regions, and ice sheets, which cover large areas like Antarctica and Greenland. Glaciers erode land and provide resources like fresh water and fertile soil. Their rapid melting is a clear indicator of global warming, contributing to rising sea levels and potentially disrupting global ocean currents and ecosystems.

Takeaways

• 🌍 Glaciers have shaped Earth's landscapes for millions of years but are rapidly disappearing due to climate change.
• ❄️ A glacier is a large, slow-moving mass of ice, classified into two groups: alpine glaciers and ice sheets.
• 🏔️ Alpine glaciers form on mountainsides and move down through valleys, reshaping landscapes by pushing soil and debris.
• 🧊 Ice sheets form broad domes that cover large areas, including valleys and mountains, with continental glaciers being the largest.
• 🌨️ Glaciers form when snow piles up and compresses over years, eventually transforming into dense glacial ice.
• 🏞️ Glaciers shape landscapes by erosion and create features like lakes, valleys, and mountains as they retreat.
• 🚰 Glaciers are a critical source of freshwater, feeding rivers and providing fertile soil for agriculture.
• 🌊 Melting ice sheets contribute to rising sea levels and disrupt ocean ecosystems and currents.
• ⚠️ Glaciers serve as indicators of climate change, with accelerated melting signaling a warning for global warming impacts.
• ⏳ If global warming continues unchecked, many alpine glaciers may vanish entirely, altering ecosystems and weather patterns.

Q & A

What are the two general types of glaciers mentioned in the script?

The two general types of glaciers are alpine glaciers and ice sheets.

How do alpine glaciers differ from ice sheets?

Alpine glaciers form on mountainsides and move through valleys, sometimes creating them by pushing soil and debris. Ice sheets, on the other hand, spread out from their centers in all directions and are not limited to mountainous areas.

Which continents have alpine glaciers, and which do not?

Alpine glaciers are found on every continent except Australia.

What are the largest types of ice sheets called, and where are they located?

The largest ice sheets are called continental glaciers, and they cover vast areas like most of Antarctica and Greenland.

How does snow transform into a glacier over time?

Snow becomes denser and more tightly packed as new snow falls and buries older layers. The dense, grainy ice that survives one melt cycle is called firn. As the firn layers accumulate and fuse, they form glacial ice.

What process causes glaciers to move?

Glaciers move through a process called compression melting, where the glacier's weight causes it to slowly shift over the land.

What landscape features are left behind as glaciers retreat?

As glaciers retreat, they leave behind landscape features such as lakes, valleys, and mountains.

What are some of the useful resources provided by glaciers?

Glaciers provide fertile soil for crops through glacial till, deposits of sand and gravel for concrete and asphalt, and they also supply fresh water through melting ice.

How do glaciers act as indicators of global warming?

Glaciers are sensitive to climate change, and their increased melting speed serves as an early warning system for global warming. The melting ice sheets also contribute to rising sea levels and impact ocean ecosystems.

What potential impacts could glacier melt have on ocean currents and weather patterns?

The addition of fresh water from melting glaciers reduces the salt content in the ocean, which could disturb the Gulf Stream and drastically alter weather patterns on land.