Glaciers: Everything You Need to Know

A glacier is a large slow moving body of ice. They form when snow accumulates over many years and turns into ice. Eventually, when it becomes thick enough, it flows like a river over land due to the influence of gravity, a process known as glacier flow. As the glacier moves, it carves out valleys, leaving behind rocks and creating features such as lakes and waterfalls.

 Glacierized areas cover over 15 million square kilometers (5.8 million square miles). During the maximum point of the last ice age, which ended about 12,000 years ago, glaciers covered about 32 percent of the total land area.

NSIDC

However, due to climate change, they are melting, and today, they only occupy around 10% of the earth’s surface. Glaciers practically exist on every continent. However, Antarctica and Greenland contain most of the world’s glacial ice.  Additionally, glaciers can persist for many centuries and even millennia. The longest-living glacier on record is the Barnes Ice Cap in Antarctica.

Formation of Glaciers

For glacial ice to form, a large amount of snow must accumulate. Therefore, a glacier forms when piles of snowflakes compress and condense into ice at higher elevations.  

With time, when the glacier becomes big enough, it slowly flows downhill under the influence of its weight and gravity. And as it does, it grinds the rocks beneath it, carving out valleys and mountains.

Since the rate of glacial ice formation is highly dependent on snowfall, this transformation process can take several decades to hundreds of years.

Besides snowfall, the temperatures must be cold enough to keep the ice condensed all year round. As a result, glaciers tend to occur only in polar regions such as Greenland and Antarctica and at high altitudes such as South America and Alaska.

Therefore, three essential conditions are required to form a glacier:

1. Cold Climate: Found in polar latitudes or high elevations.
2. Abundant Snowfall: More snow must accumulate than melts.
3. Snow Retention: Snow must remain undisturbed by avalanches or wind.

Types of Glaciers

In general, glaciers are classified into two groups: alpine glaciers, which are also known as mountain glaciers, and ice sheets, which are also referred to as continental glaciers.

Alpine Glaciers

Alpine glaciers form in the mountains at high elevations or near cool and wet coastal areas. However, most of the world’s alpine glaciers are found in high mountain ranges such as the Alps, Rockies, and the Andes.

Compared to ice sheets, alpine glaciers are much smaller and are found in areas with a lot of snowfall. The snowfall turns into ice and slowly moves down the mountainside. As the ice flows, it melts and forms rivers and valleys.

Ice Sheets

On the other hand, ice sheets are huge masses of ice covering a large geographical area. It extends more than 50,000 square kilometers (19,300 square miles). Ice sheets are very old, thick, and dome-shaped. They are found in very cold places with very little precipitation.

Once they covered much of the Northern Hemisphere during a series of Pleistocene Ice Ages. Now, Earth has just two ice sheets, one covers most of Greenland, the largest island in the world, and the other spans across the Antarctic continent.

Together, the Antarctic and Greenland Ice Sheets contain more than 99 percent of the freshwater ice on Earth.

As ice sheets move, they cover vast areas, including plains, valleys, and even mountains. However, they flow very slowly and can take thousands of years to move just a few meters. Ice sheets cover entire continents. During the Last Glacial Maximum, roughly 20,000 years ago, the Laurentide Ice Sheet covered much of North America, and its weight created basins that now hold the Great Lakes.

Distribution of Glaciers

Glaciers exist on every continent except Australia. Approximate distribution is:

• 91% in Antarctica
• 8% in Greenland
• Less than 0.5% in North America (about 0.1% in Alaska)
• 0.2% in Asia
• Less than 0.1% are in South America, Europe, Africa, New Zealand, and Indonesia.”

How Do Glaciers Change The Landscape?

The glacial movement is very powerful, and its impact on the bedrock is important in forming most of the world’s iconic landforms. It shapes the landscape through erosion and deposition.

Erosive Changes

With erosion, as the glacier moves downhill, it picks up rocks and boulders, which freeze in the glacier, eroding and carving the bedrock underneath. They often curve out U-shaped valleys with vertical cliffs.

In addition, glacial erosion also forms hills, deepens streambeds, and creates basins that eventually become lakes. For example, The Great Lakes of the United States were carved during the last ice age as the glaciers retreated.

Changes Through Deposition

Deposition is another way through which glaciers alter the landscape. A deposition is what a glacier leaves behind when it retreats or melts. As they move, glaciers deposit what they have picked on the way. And this includes boulders, sand, gravel, and soil. These materials are referred to as glacial till.

The material that a glacier picks up or pushes as it moves forms moraines. A moraine accumulates glacial till to form either a ridge or a mound. There are three types of moraines;

1. Lateral moraine: Forms when materials are deposited along both edges of a moving glacier
2. Medial moraine: Forms when materials are deposited at the center of where two glaciers meet. 
3. Terminal moraine: Forms when materials are deposited at the end of a glacier.

One of the most distinctive landform features that moraines forms are drumlins. Drumlins are hills, and they vary in size. However, they are characterized by a steep side and a sloping side. The sloping side is usually the side that is closest to the glacier as it retreats.  

The Importance of Glaciers

Glaciers have a major significance in the world ecosystem for several reasons:

1. Glaciers are a key source of freshwater. They store a large amount of freshwater, which is essential for humans, animals, and plants.
2. They help regulate the earth’s temperature. They do this by reflecting excess radiation into space, thus cooling the planet.
3. They also serve as important indicators of climate change and global warming. This is because any physical change in them provides a clear indication of the rate of temperature changes.
4. Glacial till, which is deposited by glaciers as they move, offers fertile soil for crop cultivation.

How Does Climate Change Affect Glaciers?

As each day passes, our planet is getting warmer. Temperatures are rising at a faster rate than before. The emission of greenhouse gases into the atmosphere significantly contributes to the rise of global temperatures. And as the planet gets warmer, glaciers are shrinking at an alarming rate.

The melting of glaciers highly contributes to the rising sea levels. This leads to increased coastal erosion and high storm surges caused by more frequent and powerful hurricanes and typhoons.

As of 2023, the Greenland and Antarctic ice sheets are melting four times faster than before and are significantly contributing to the global sea level rise.

Glaciers play an important role in the earth’s system; therefore, urgent conservation measures are required to minimize climate change and its effects on glaciers.

Conservation of Glaciers

In December 2022, the United Nations passed a resolution declaring 2025 as the International Year of Glaciers’ Preservation, marking a crucial step in acknowledging the urgent need to protect these vital components of Earth’s ecosystems.

The resolution emphasizes the essential role glaciers play in maintaining ecological balance, supplying freshwater resources, and regulating climate and hydrological patterns. As climate change intensifies, the conservation of glaciers has become increasingly critical. The General Assembly also highlighted the numerous hazards posed by glacial retreat and thaw in mountainous regions, including slope instability, increased flooding, landslides, and avalanches, which are now occurring more frequently, in new locations, and at different times of the year. These effects cascade down to valleys and lowland areas, leading to issues such as reduced agricultural yields.

The Glaciers of the World

From the retreating beauties in the Rockies to the icy ranges of Pakistan, here are some of the most unique icy giants:

Jakobshavn Glacier (Greenland)

The Jakobshavn Glacier is one of the fastest-moving glaciers, crucial for studying climate change. It is known as the glacier that calved the iceberg responsible for the sinking of the Titanic.

Vatnajökull (Iceland)

Vatnajökull is the Europe’s largest glacier by volume, home to numerous active volcanoes underneath. It is a site of significant geological research on glacial movement and volcanic activity and central to Icelandic sagas, a backdrop for many myths and modern films.

Perito Moreno Glacier (Argentina)

The Perito Moreno Glacier is one of the few advancing glaciers in the world, an anomaly in global glacial retreat trends. It is named after Francisco Moreno, an explorer who significantly contributed to the mapping of Patagonia. It is a major tourist attraction, inspiring awe and wonder in visitors from around the globe.

Fox and Franz Josef Glaciers (New Zealand)

The Fox and Franz Josef Glaciers are unique due to their low altitude and rapid descent into temperate rainforest. Explored extensively during the 19th century, it is pivotal in understanding glacial dynamics in maritime climates. It is sacred to the Māori people, featuring prominently in local legends and stories.

Hubbard Glacier (Alaska, USA)

The Hubbard Glacier is known for its rapid advance and periodic ice dam formations that create temporary lakes. It was documented by European explorers in the late 19th century, vital for studying glacial advance and retreat cycles. As a part of the spectacular scenery in Glacier Bay National Park, it is integral to Alaskan indigenous cultures.

Khumbu Glacier (Nepal)

Khumbu Glacier is the highest glacier in the world, located on the slopes of Mount Everest. Being integral to the climbing routes of Everest, it is a silent witness to human triumphs and tragedies. It holds spiritual significance in Tibetan Buddhism, considered a pathway to enlightenment.

Athabasca Glacier (Canada)

Athabasca Glacier is a part of the Columbia Icefield, providing critical data on glacial health in the Rockies and a landmark for early explorers and a key site for glaciological research in North America. It serves as a focal point for understanding the impact of climate change on Canada’s natural heritage.

Lambert Glacier (Antarctica)

Lambert Glacier is the world’s largest glacier, crucial for studying Antarctic ice dynamics and sea-level rise. It was discovered during the 1950s, a testament to human curiosity and the drive to explore the unknown. Often featured in scientific documentaries, raising awareness about polar ice and its global significance.

Baltoro Glacier (Pakistan)

Baltoro Glacier is one of the longest glaciers outside the polar regions, key for studying high-altitude glaciology. A vital route for mountaineers aiming to summit K2, the world’s second-highest peak. Embedded in the heritage of the local Balti people, who live in its shadow and rely on its meltwater.

Siachen Glacier (India/Pakistan)

Siachen Glacier is the world’s highest battleground, highlighting the intersection of environmental science and geopolitics. It has a contentious border area, a symbol of the enduring conflict between India and Pakistan. It is known as the “Third Pole,” representing the harsh realities of life and conflict at extreme altitudes.

Crown of the Continent

Whilst not a glacier in itself, Glacier National Park has a worthy mention in this list, as it contains a total of 25 named glaciers in this one place alone. Located in the Rocky Mountains of Montana, running all the way to the Canadian border, it is also nicknamed the ‘Crown of the Continent’ for a reason.

Established as a National Park in 1910, this mountain range was carved by prehistoric ice rivers and features alpine meadows, deep forests, waterfalls, and around 200 sparkling lakes, in addition to its glistening glaciers. It’s crossed by the mountainous Going-to-the-Sun Road.

FAQs