An ice age, or more precisely, a glacial age, is a period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers. Within a long-term ice age, individual pulses of cold climate are termed "glacial periods" (or alternatively "glacials" or "glaciations" or colloquially as "ice age"), and intermittent warm periods are called "interglacials". Glaciologically, ice age implies the presence of extensive ice sheets in the northern and southern hemispheres. By this definition, we are still in the ice age that began 2.6 million years ago at the start of the Pleistocene epoch, because the Greenland and Antarctic ice sheets still exist.
Read more about Ice Age: Origin of Ice Age Theory, Evidence For Ice Ages, Major Ice Ages, Glacials and Interglacials, Positive and Negative Feedbacks in Glacial Periods, Causes of Ice Ages, Recent Glacial and Interglacial Phases, Effects of Glaciation
Famous quotes containing the words ice and/or age:
“A young person is a person with nothing to learn
One who already knows that ice does not chill and fire does not burn . . .
It knows it can spend six hours in the sun on its first
day at the beach without ending up a skinless beet,
And it knows it can walk barefoot through the barn
without running a nail in its feet. . . .
Meanwhile psychologists grow rich
Writing that the young are ones’ should not
undermine the self-confidence of which.”
—Ogden Nash (1902–1971)
“The complete life, the perfect pattern, includes old age as well as youth and maturity. The beauty of the morning and the radiance of noon are good, but it would be a very silly person who drew the curtains and turned on the light in order to shut out the tranquillity of the evening. Old age has its pleasures, which, though different, are not less than the pleasures of youth.”
—W. Somerset Maugham (1874–1965)