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What is Cryosphere? How does it affect Global Climate?

Cryosphere is the term used collectively for the portions of Earth surface, where water is present in a frozen state. It includes:

  • Snow Cover
  • Glaciers
  • Ice Sheets
  • Ice Shelves
  • Freshwater Ice
  • Sea Ice
  • Icebergs
  • Permafrost
  • Ground Ice

The word “Cryo” has come from Greek meaning “Icy Cold”. The term Cryosphere was first introduced by Dobrowolski (1923) and Barry et.al. (2011) and elaborated by Shumskii (1964).

Cryosphere is an integral part of the global climate system. It has important linkages and feedbacks with the atmosphere and hydrosphere. For example:

  • It affects surface energy and discharge of moisture, as it releases large amount of freshwater, when snow ice melts.
  • Release of freshwater due to melting and its locking due to freezing (both) are directly linked to the thermohaline

The global distribution of the components of the Cryosphere (from Hugo Ahlenius, courtesy UNEP/GRID-Arendal,Norway). http://upload.wikimedia.org/wikipedia/commons/b/ba/Cryosphere_Fuller_Projection.png. See color version in plates section

Cryosphere has deep influence on atmospheric processes such as formation of clouds and precipitation. Any change in the amount of freshwater coming from Cryosphere into lands and oceans can affect surface hydrology.

How Cryosphere Affects Global Climate?

  • Cryosphere is linked to Ice-Albedo mechanism

  • Snow-cover, oceans and floating ice provides insulation to the land surface. Absence of snow cover will result into higher mean-annual surface temperature. Absence of snow cover will also lead to severe winter cooling of the land surface and increase in permafrost (permanently frozen subsoil) in near pole areas.
  • Cryosphere is also related to any eustatic (uniform) changes in global sea level. 1mm rise in Eustatic Sea level require 360 Giga Tonnes of ice.
  • It also affects latent heat storage (involved in phase changes) between ICE WATER
  • Permafrost modulates water and energy discharges and exchange of carbon (specially methane) between land and atmosphere.

According to the study conducted by Anthony and Bamber of Bristol University, Cryosphere is far more sensitive to the climate change than it has been estimated. They have tried to prove it through examples of melting margins of Greenland glaciers, reduction of Arctic Summer Ice, melting of Alpine-Himalayan glaciers, decline of west Antarctic ice-sheet etc. Sea level rise due to receding glaciers could alter ocean currents and bring irreversible changes in the regional climate. It could displace million of peoples from their homes. Therefore, we may say that it is not the Cryosphere at risk but potentially entire global climate regime.

 

About the Author: Dr. S. Fazal Daoud Firdausi is an expert in Human Geography and teaches Geography GS & Optional at Competitive Examinations Centre, Savitribai Phule Pune University, Pune, India   

 

References:

Barry, R., Yew Gan, T. (2011) The Global Cryosphere – Past, Present and Future, Cambridge University Press, London.

Slaymaker, O, Kelly, E.J. (2007) The Cryosphere and Global Environmental Challenge, Blackwell Publishing, Oxford

Bamber, J. et. al. (2004) Mass Balance of the Cryosphere, Cambridge University Press, London.