Ice Sheets and the Igloo Effect

Igloos are ingenious structures in which ice and snow is used to build living quarters that can hold temperatures as high as 10 to 20 degrees Celsius if fitted with animal skins and blankets on the inside.

Even without any insulating material on the inside, an igloo can reach above freezing temperatures on the inside with no other heating than the body heat of its occupants.

Considering that outside temperatures on Greenland, where these structures are made, can fall well below freezing, the relatively high temperatures that can be achieved on the inside is quite remarkable.

By From [1],

PD image from National Oceanic and Atmospheric Administration(corp1528),

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What this shows is that ice and snow are thermal insulators. They can therefore be used to keep things relatively warm.

This does not only apply to human dwellings, but snow and ice structures in general. The snow that falls every winter in arctic regions shields small animals from the cold. When temperatures drop to well below freezing, rodents and other small animals scurry through the undergrowth in search of seeds and foliage left from the summer without being much affected by the low temperatures.

The ice sheets covering Greenland and the Antarctic are similarly keeping conditions at ground level relatively warm. While both places can see air temperatures drop far below freezing during winter, temperatures below the ice hardy budge from what it is during summer.

Since our planet generates heat from within, an expanding ice sheet can be likened to someone putting on a sweater. It keeps heat from radiating into space.

A thin sweater helps. A thicker sweater helps even more, and if the sweater becomes very thick, it can even get a little too warm.

Similarly with an ice sheet: A thin one will keep things from getting terribly cold at ground level. A thicker one will keep things in equilibrium, while a very thick one may result in the ice starting to melt from below.

During periods of glaciation, the surface of our planet is less exposed to the atmosphere, and can in fact start to heat up even as air temperatures drop.

This may explain the events that took place during the early Holocene when all the glaciers in Norway disappeared completely.

At first glance, it seems odd that the period immediately after the great ice age should be the warmest period of the Holocene. However, if we suppose that the ice sheets that covered our planet had caused the planet to overheat due to the igloo effect, then the disappearance of the great ice sheets would be like an athlete taking off his sweater immediately after a Marathon run. He remains hot for some time before cooling down through radiation.

The sudden disappearance of the ice sheets of the great ice age was almost certainly due to heat from below. Once the ice sheets had disappeared, the heat continued to radiate for a considerable time before cooling down to the present level.