Q8. How does the cryosphere affect global climate? UPSC MAINS 2017 GS I

ANSWER

The cryosphere is those portions of Earth’s surface where water is in solid form. It includes sea ice, lake ice, river ice, snow cover, glaciers, ice caps, ice sheets, and frozen ground (which includes permafrost).

The cryosphere is an integral part of the global climate system with important linkages and feedbacks generated through its influence on surface energy and moisture fluxes, clouds, precipitation, hydrology, atmospheric and oceanic circulation. Through these feedback processes, the cryosphere plays a significant role in the global climate and in climate model response to global changes.

The most important effect of cryosphere is that it influence the earth’s energy balance. As snow and ice have high albedo they reflect much of the insolation, which helps in cooling of the earth. Thus, presence or absence of snow and ice affects the heating and cooling of Earth’s surface.

But now with global warming cryoshpere is melting which is resulting in sea level rise, threatening the small island countries the most. Again with the melting of the ice caps the rate of albedo gets decreased which in turn increase the temperature and set a vicious cycle in motion (ice melts- decreasing albedo- increasing temperature-more ice melts) often called feedback loop.

Moreover the permafrost of the polar region has trapped tonnes of carbon inside its soil. If melting of ice occurs, this carbon will be released in form of methane- a powerful greenhouse gas- which will catalyze global warming.

Also at polar regions, sea-water is converted into sea ice. As a result, surrounding water gets colder and saltier which sinks and initiates thermohaline circulation patterns across the oceans of the world. These Ocean currents act like a conveyer belt, transporting warm water from the equator toward the poles and cold water from the poles back to the tropics. These currents regulate global climate and affect rain and drought situation.

Thus,we can say that cryosphere has direct and indirect bearing on the global climate and it plays a vital role in stabilizing the Earth’s climate and the entire biosphere as well.