Ice age

An ice age is a period of long-term downturn in the temperature of Earth's climate, resulting in an expansion of the continental ice sheets, polar ice sheets and mountain glaciers ("glaciation"). Glaciologically, ice age is often used to mean a period of ice sheets in the northern and southern hemispheres; by this definition we are still in an ice age (because the Greenland and Antarctic ice sheets still exist). More colloquially, when speaking of the last few million years, ice age is used to refer to colder periods with extensive ice sheets over the North American and European continents: in this sense, the last ice age ended about 10,000 years ago. This article will use the term ice age in the former, glaciological, sense; and use the term 'glacial periods' for colder periods during ice ages and 'interglacial' for the warmer periods.

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During the last few million years, there have been many glacial periods, occurring initially at 40,000-year frequency but more recently at 100,000-year frequencies. These are the best studied. There have been four major ice ages in the further past.

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Temperature: Temperature is the physical property of a system which underlies the common notions of "hot" and "cold"; the material with the higher temperature is said to be hotter. Temperature is a measure of the average kinetic energy of the particles in a sample of matter. In other words, temperature is a meas...

Climate: The climate (ancient Greek: κλίμα) is the weather averaged over a long period of time. A descriptive saying is that "climate is what you expect, weather is what you get." The Intergovernmental Panel on Climate Change (IPCC) glossary definition is:...

Ice sheet: An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² (19,305 mile²). The only current ice sheets are Antarctic and Greenland; during the last ice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of Canada and North Amer...

Ice age related Images and Photos (experimental)

Ice Age 2	Ice Age DVD	Ice Age DVD Game	Ice Age: The Meltdown DVD
Ice Age: Dawn of the Dinosaurs DVD	Ice Age 2 The Meltdown Forest Moment Framed Giclee Print	Cavemen During the Ice Age after a Sketch by Professor Klaatsch Late 19th Century	Reindeer Hunting During the Late Ice Age High Souabe After Sketch by Professor Klaatsch c.1900
Mammoth Herd During the Ice Age	Ice-T	Ice T	Ice Cube