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At
present, year-round ice covers 11% of the land area and 7% of the world
ocean. |
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Surface ice of any depth is a much more
effective reflector of solar radiation than the underlying surface. |
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Sea ice is a good insulator and allows air
temperature to be very different from that of the seawater under the ice. |
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One
major climate effect of sea ice is to seal off the underlying ocean from
interaction with the atmosphere. |
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Without
an sea ice cover, high-latitude oceans transfers large amount of heat to
the atmosphere, especially in winter. |
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With an
sea ice cover, the heat flux into the atmosphere is stopped. In addition,
the ice surface absorbs little incoming solar radiation. Winter air
temperature can cool 30°C or more near a sea-ice cover. |
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Ice cores retrieve climate records extending
back thousands of years in small mountain glaciers to as much as hundreds
of thousands of years in continental sized ice sheets. |
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The antarctic ice sheet has layers that extend
back over 400,000 years. |
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The Greenland ice sheet has layers that extended
back 100,000 years. |
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The Antarctic Ice Sheet holds the equivalent in
seawater of 66 meters of global sea level. |
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The Greenland Ice Sheet holds the equivalent of
6 meters of global seawater. |
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Notes