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.

Outlines

00:00

❄️ Glaciers: Shaping Our Planet

Glaciers have played a crucial role in shaping Earth's landscapes over millions of years. However, due to climate change, glaciers are melting at an accelerated rate, affecting oceans, weather patterns, and life on Earth. These large ice masses move slowly over land and come in two types: alpine glaciers, which form on mountains and carve valleys, and ice sheets, which spread out across plains and mountains, covering vast areas like Antarctica and Greenland.

🏔️ The Formation and Movement of Glaciers

Glaciers form when layers of snow accumulate over years, eventually compressing into dense ice called firn. As snow continues to build up, the firn turns into glacial ice, which becomes thick enough to move under its own weight through a process known as compression melting. This movement causes glaciers to erode the land beneath them, creating lakes, valleys, and mountains as they retreat.

🌾 Resources Provided by Glaciers

Glaciers leave behind several important resources. Glacial till, a mixture of materials deposited by glaciers, enriches soil for agriculture. Additionally, sand and gravel from glaciers are essential for building materials like concrete and asphalt. Many rivers rely on glaciers for their water supply, making glaciers a vital source of freshwater for ecosystems and human use.

🌡️ Glaciers as Indicators of Climate Change

The rapid melting of glaciers due to global warming serves as a clear indicator of climate change. Melting ice sheets contribute to rising sea levels, which threaten coastal areas. The loss of glacial ice also reduces freshwater availability, disrupting both land and ocean ecosystems. Moreover, changes in ocean salinity from melting glaciers could impact weather patterns, highlighting the critical role glaciers play in Earth's climate system.

Keywords

💡Glaciers

Glaciers are large masses of ice that move slowly over land. They have played a significant role in shaping Earth's landscapes over millions of years. In the video, glaciers are described as key forces in shaping valleys, mountains, and lakes, while also providing important resources such as freshwater.

💡Climate Change

Climate change refers to long-term shifts in temperature and weather patterns, primarily caused by human activities like burning fossil fuels. The video emphasizes how climate change is accelerating the melting of glaciers, leading to rising sea levels, changing ecosystems, and potentially drastic weather changes.

💡Alpine Glaciers

Alpine glaciers are glaciers that form on mountainsides and move down through valleys. These glaciers are found on all continents except Australia. The video explains how alpine glaciers shape the landscape by pushing materials like soil and rocks out of their path as they move.

💡Ice Sheets

Ice sheets are massive, broad glaciers that spread out from their centers, covering large areas. Unlike alpine glaciers, they are not confined to mountainous regions and are found in places like Antarctica and Greenland. The video notes how these ice sheets contribute to rising sea levels when they melt.

💡Firn

Firn is dense, grainy ice that forms after snow accumulates and compresses over several years. This ice is a crucial stage in the formation of glaciers. The video discusses how firn develops into glacial ice through further compression, illustrating the slow formation process of glaciers.

💡Glacial Ice

Glacial ice forms when firn becomes thick enough that the grains fuse together under pressure. This heavy, dense ice makes up the bulk of glaciers, which can then begin to move and shape the land. The video highlights glacial ice as a critical part of glacier movement and erosion.

💡Rising Sea Levels

Rising sea levels refer to the increase in the global sea level due to melting ice sheets and glaciers. The video explains that as ice in Antarctica and Greenland melts, it adds significant amounts of freshwater to the oceans, which can lead to flooding and changes in ocean ecosystems.

💡Erosion

Erosion is the process by which glaciers wear away the land as they move. Glaciers erode valleys, mountains, and other landforms, leaving behind dramatic landscapes. The video describes erosion as one of the key impacts of glacial movement, reshaping entire regions over time.

💡Global Warming

Global warming is the rise in Earth's average temperature, primarily due to human activities like burning fossil fuels. The video emphasizes global warming as the driving force behind the accelerated melting of glaciers, which threatens to disrupt ecosystems, ocean currents, and weather patterns.

💡Freshwater

Freshwater is a critical resource provided by glaciers, as many rivers are fed by melting ice. The video highlights that the loss of glaciers due to global warming could reduce the availability of freshwater, impacting plants, animals, and human populations that rely on it for survival.

Highlights

Glaciers have been shaping our world for millions of years, but they are disappearing due to climate change.

A glacier is a massive ice formation that moves slowly over land, altering landscapes and affecting global systems.

Glaciers are classified into two groups: alpine glaciers, which form on mountainsides, and ice sheets, which spread from broad domes.

Alpine glaciers move down through valleys and can create valleys by displacing soil and rock.

Ice sheets form in non-mountainous areas and spread in all directions, covering vast terrains including entire mountains.

The largest ice sheets, known as continental glaciers, cover regions like Antarctica and Greenland.

Glaciers form over many years as snow accumulates, compresses, and transforms into dense, grainy ice called firn, eventually becoming glacial ice.

Glaciers move under their own weight through a process called compression melting, eroding the land beneath and around them.

The latest retreat of glaciers, starting less than 20,000 years ago, left behind significant landscape features such as lakes and valleys.

Glaciers provide valuable resources, including fertile soil, sand, gravel, and freshwater, essential for crops and human use.

Melting glaciers contribute to rising sea levels and alter ocean ecosystems and currents, impacting weather patterns on land.

Glaciers serve as early indicators of climate change; accelerated melting warns of broader environmental impacts.

As glaciers melt, they add freshwater to the ocean, which can disrupt the salinity balance, affecting ocean currents like the Gulf Stream.

Glaciers' sensitivity to climate change makes them crucial in understanding and predicting future environmental shifts.

Unchecked global warming threatens the existence of many alpine glaciers, posing significant risks to ecosystems and freshwater resources.

Transcripts

- [Narrator] Glaciers have been shaping

our world for millions of years.

But as climate change warms the planet,

glaciers are disappearing, not only altering the landscapes

they leave behind, but changing our oceans, weather,

and life on earth as we know it.

A glacier is a huge mass of ice that moves slowly over land.

Glaciers can be classified into two general groups

alpine glaciers and ice sheets.

Alpine glaciers form on mountainsides

and move downward through valleys.

Sometimes, they create valleys by pushing dirt, soil,

and other materials out of their way.

These glaciers are found

on every continent except Australia.

Ice sheets, unlike alpine glaciers,

are not limited to mountainous areas.

They form broad domes and spread out

from their centers in all directions.

As ice sheets spread, they cover everything around them

with a thick blanket of ice, including valleys,

plains, and even entire mountains.

The largest ice sheets are called continental glaciers.

They cover vast area including most of Antarctica

and the island of Greenland.

Glaciers can form over years

when more snow piles up and melts.

Soon after falling, the snow begins to become denser

and more tightly packed.

When new snow falls and buries the previous years snow,

the bottom layer becomes even more compressed.

The dense, grainy ice that has survived

one year's melt cycle is called firn.

When the ice grows thick enough, the firn grains fuse

into a huge mass called glacial ice.

The glacier may begin to move under its own weight,

through a process called compression melting.

As they move, glaciers erode or wear away

the land beneath and around them.

When glaciers began their latest retreat

less than 20,000 years ago, they left behind

many landscape features,

such as lakes, valleys, and mountains.

Glaciers provide people with many useful resources.

Glacial till provides fertile soil for growing crops.

And, deposits of sand and gravel are used

to make concrete and asphalt.

Many rivers are fed by the melting ice of glaciers.

The most important resource provided

by glaciers is freshwater.

Earth's average temperature has been increasing

dramatically for more than a century.

Glaciers can act as indicators of global warming

and climate change in several ways.

Melting ice sheets contribute to rising sea levels.

As ice sheets in Antarctica and Greenland melt,

they raise sea levels, adding fresh water

to the ocean every day.

The loss of glacial ice also reduces the amount

of fresh water available for plants and animals on land.

Large additions of fresh water change

the ocean ecosystem, as well ocean currents.

Additionally, less salt in the ocean could disturb

the gulf stream, drastically changing

the weather on land as well.

Since glaciers are so sensitive to climate change,

the increased speed of glacier melt

is an early warning system for the rest of the planet.

And if global warming goes unchecked, many, if not all,

alpine glaciers could disappear completely.

(soft entertaining music)