Deglaciation and Threats

Deglaciation and Threats

Deglaciation is a geological process that occurs when the glacier or ice sheet flows away from the zone of accumulation and gains enough speed to break into smaller pieces. This is referred to as calving, and can occur when a glacier falls over a steep area, known as an icefall.

Causes of Deglaciation

Global warming: Humans are warming the planet through the release of greenhouse gases (GHGs) into the earth's atmosphere. Greenhouse gases like carbon dioxide, methane, and nitrous oxide are emitted when the industry (mining, burning fossil fuels), transport (cars, planes, trucks, and ships), agriculture (animal farms, deforestation for crops), and other human activities that lead to deforestation burn fossil fuels; these gases collect in the atmosphere where they prevent heat escaping from the earth.

Ocean warming: Because the oceans absorb 90% of the Earth’s warmth and most glaciers are near the poles, global warming would be less visible if not for oceans. This is why scientists refer to deglaciation as “ocean warming.” Oceans also cause sea levels to rise along with the temperature: warm water expands.

Rapid industrialisation: Recent research on the phenomenon of deglaciation shows that it was intensified by industrialisation. The melting of glaciers began on a large scale from the early 20th century. The global temperature at that time was far below today's level. Therefore, warm air emissions could not be effective in melting the glaciers. Thus, scientists were puzzled why glaciers was melting so rapidly since that time.

Impacts of Deglaciation

Raised sea level: Sea level rise is likely to continue for centuries, posing a threat to populated coastal regions and low-lying islands. With the majority of glaciers in Asia and North America (the two coldest continents) projected to disappear, sea-level rise could accelerate beyond Antarctica in the long term.

On mountain glaciers: The famed snows of Mount Kilimanjaro have melted more than 80% in the last century as the ice fields that once covered them until early this millennium disappeared. This was announced by a team of scientists who have been studying glaciers for several years.

In the Northern Hemisphere: In the Northern Hemisphere, spring freshwater ice breakup in watersheds now occurs nine days earlier than it did 150 years ago, and autumn freeze-up ten days later. The changes could have cascading effects on lake and river ecosystems as well as on regional economies

Melting of Thwaites Glacier: Vast glaciers are hazardous to the planet's oceans as they melt faster than other areas of the ice. One of them is the Thwaites Glacier, which if melted is equal to contributing 40 feet of sea level. The rate at which it melts is staggering and greater than scientists once predicted.

Disappearance of species: Glaciers are the natural habitat of a number of animals, both terrestrial and aquatic. The penguins and polar bears depend on the frozen ice to get food and shelter. Many animals have been forced to move their territories to more habitable areas, at some locations the migration has led to conflicts of interest with human beings.

About the Himalayan Glaciers

Himalayan glaciers are the largest body of ice outside the polar caps and are the source of water for the innumerable rivers that flow across the Indo-Gangetic plains – they're also a major tourist draw and an intrinsic part of the pristine Himalayan landscape.

Glaciers themselves are relatively unexplored in unaccustomed ways, with selected numbers having been done every now and then in certain parts of the Himalayan region.

Himalayan glacial snowfields store about 12,000 km3 of freshwater.

15,000 Himalayan glaciers form a unique reservoir which supports perennial rivers such as the Indus, Ganga and Brahmaputra which, in turn, are the lifeline of millions of people in South Asian countries (Pakistan, Nepal, Bhutan, India and Bangladesh).