What is the Cryosphere?

The frozen parts of Earth – the cryosphere – are melting at unprecedented rates causing irreversible changes to our planetary ecosystem.

What is the cryosphere:

• Areas of Earth where water exists in any of its frozen states.
• All water is in a solid state (snow, snow ice, ice sheets, ice shelves, icebergs, glaciers, and permafrost).
• Its main regions include the Arctic, Antarctic, and high mountain areas such as the Himalayas.

Climate change and cryosphere properties

There are three key concepts for understanding why the cryosphere is so influential on the Earth’s climate:

1. Albedo effect or surface reflection: Ice helps us keep cool – but not in the way you might think. Ice and snow are more reflective than land or water, meaning that they reflect more of the thermal radiation from the sun’s heat back into the atmosphere than they absorb.  
2. Heat transfer: Ice helps us keep warm. It is a natural insulator because heat travels more slowly through ice and snow than through air or water. Snow cover also insulates the soil, keeping the temperature stable, and in some instances up to 5 degrees warmer in the coldest parts of winter.
3. State changes: The melting and freezing of ice changes saltwater concentration, with more ice creating saltier, denser water that sinks to the bottom. This process drives global ocean currents, moving warmer water from tropical regions towards the north and south poles, which in turn affects global weather patterns.

The cryosphere comprises about 10% of the Earth’s surface, but this is decreasing with rising temperatures due to global warming. It is closely linked to the atmosphere (air), hydrosphere (water), lithosphere (rock crust), and biosphere (ecosphere). For example, solar radiation and the greenhouse gas effect are increasing the sublimation of snow and ice from the mountains and glaciers, as well as the evaporation and evapotranspiration from lakes, rivers, and forests. The thawing of the different kinds of permafrost (continuous, discontinuous, and sporadic) also releases methane from the ground and other aerosol particles that contribute to the global greenhouse effect.

Melting glaciers mean more water flowing into streams, rivers and glacial lakes – increasing the risk of glacial lake outburst flooding (GLOF), which is already occurring in mountainous regions such as the Himalayas. The natural cycle of the five interrelated ‘spheres’ of our planetary climate system is being disrupted, causing unprecedented alterations with unknown effects. What is certain, however, is that there will be no more glaciers in the future.

Cascading climate change facts

• Permafrost thawing increases CO2 in the atmosphere, leading to more global warming, and more permafrost loss.
  • Around 1,400 gigatons of CO2 are stored in the permafrost, which is approximately twice the amount that is currently in the atmosphere.
• Loss of ice cover leads to more global warming as the planet loses surface reflection capacity, which leads to more ice loss.
  • When sunlight hits ice and snow, about 90% of it bounces back into space, compared to only 30% reflected from bare ground. As ice melts, darker surfaces absorb more heat, leading to additional warming. This creates a feedback loop where less ice means more heat absorption, which causes more ice to melt.
• Glacier surges are accelerated shifts and movements of glaciers that can obstruct rivers.
  • Glacier surges are not directly related to climate change but can have significant effects on the creation or enlargement of glacier lakes that can lead to glacier lake outburst flooding (GLOF).