Cryosphere

The cryosphere is the portions of the Earth’s surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps, ice sheets, and frozen ground like permafrost. Due to its very nature the cyrosphere is always changing in its area and volume and overlaps quite a bit with the hydrosphere. This is an integral part of the global climate system. It has important linkages and feedbacks generated through its influence on surface energy and moisture fluxes, cloud formation, precipitation, and atmospheric and oceanic circulation. This means that it plays an important role in the global climate.

The residence time of water in each sub-system(snow, ice, permafrost) varies widely. Snow cover and freshwater ice are essentially seasonal. Most sea ice, except for ice in the central Arctic, lasts only a few years if it is not seasonal. A water particle in a glacier, ice sheet, or ground ice(permafrost) may remain frozen for 10-100,000 years or longer, and deep ice in parts of East Antarctica may have an age approaching 1 million years. Most of the world’s ice volume is in Antarctica, but by area Northern Hemisphere winter snow and ice is the largest, amounting to an average 23% of hemispheric surface area in January. The large area and the important climatic roles of snow and ice, indicate that the ability to observe and model snow and ice-cover extent, thickness, and radiative and thermal properties is of particular significance for climate research.

The cryosphere is the part of the atmosphere that shows some of the most easily observable effects of global warming. As the oceans warm, the ice recedes. The melting ice can raise the levels of the oceans around the world. It is actually a cycle. As the ice melts it allows the planet to stay warmer and more ice melts. NASA satellites have documented a rapid decrease in ice sheets that coincides with a rapid rise in global sea levels.

There are two good article about this part of the atmosphere: one is dedicated to the cryosphere and the other is about all of its components. Here on Universe today we have a great article about climate changes here on Earth. Astronomy Cast offers a good episode about the source of atmospheres.

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