The ice in Greenland did not melt during the Holocene otherwise there would
be no ice cores stretching back to the Eemian 120 k years ago. OTOH it
does seem likely that the ice they did melt during the Eemian when global
temperatures were 2-3C higher than today, which explains why the ice cores
from Greenland only go back 120,000 years.
Coby is right. It is a lot more complicated than is generally believed.
This also applies to the forcing. For an ice sheet to form it needs a
cold summer when the snow never retreats, but for an ice sheet to
melt it needs a warm winter, which implies an increase in greenhouse
gases. Those gases are CO2 and H2O, and their increase is caused
by warm oceans during the summer. The current melting of the ice
is a result of the increased CO2 thanks to Man.
Land and sea behave differently.
Land ice and sea ice behaves differently.
Summer and winter have different effects.
Greenhouse gases and solar radiation have different effects.
Of course the last point is not widely recognised since it is generally
believed that the forcing occurs near the tropopause for both solar and
greenhouse gases.
Although a rise of 2C will not melt the Antarctic ice at the high altitude
of the South Pole, it could cause a warm South Pacific ocean to emit
more CO2 which would melt some ice exposing a low albedo surface
which also causes warming and more melting of the ice.
Cheers, Alastair.
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