Glaciers - Printable Version
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Glaciers - Sunsettommy - 03-14-2010 12:41 AM
Illinois Glacial History
In approximately 4.6 billion years of Earth history, there have been three major episodes of glaciation. The Varangian glaciation occurred during the Proterozoic part of the Precambrian period about 700 million years ago (m.y.a.). The next one happened in the late Paleozoic Era around 300 m.y.a. The most recent period of glaciation started approximately 1.6 m.y.a. and ended about 10,000 years ago.
Today, glaciers contain nearly 75% of the world’s fresh water supply in ice that covers about 10% of land area. In contrast, ice covered as much as 30% of total land area during the most recent ice age. The largest concentration of ice today is the Antarctic ice sheet, up to 4,200 meters thick in some areas, and in the Greenland ice sheet. The remainder of glaciers is located in montane regions and in ice caps in polar seas. If climate were to suddenly warm enough to melt all land ice, there would be a eustatic sea level rise of about 70 meters. Sea level has risen about 100 meters since the last glacial maximum 20,000 years ago. Potential causes of Ice Ages and glacial cycles are variations in lithospheric plate configurations, changes in atmospheric and seawater circulation patterns, changes in atmospheric composition, and Milankovitch orbital variations.
RE: Glaciers - Richard111 - 04-16-2010 10:29 AM
Interesting read, thanks SST. But as usual I am disapointed at the lack of specific information. There is talk of glacier melt rates in cubic mile per year but no indication of the temperature range or total volumes of ice.
What I was hoping to find was an average melt rate of all glaciers in cubic miles per year but it seems glaciers do not all melt at the same time. Contrary beasts.
The reason is these constant claims of future sea level rise in the order of about 1 meter because of current global warming etc. etc.
It is easy to work out how much ice must melt for a 1 meter sea level rise, 96,000 cubic miles (+/- a little). It is also easy to work out the energy required. See post #57 in Laymans Struggles.
What I can't find an answer for is how hot must the air be and for how long this hot air is applied, i.e. winds etc. to melt the required ice from the land. Rough guesses using specific heat values for air and ice work out to thousands of years, yet these warmists claim it can happen in the next 100 years or so. Where is their supporting data?