When Did The Ice Age End?
The grand Ice Age occurred at some point in the Pleistocene era, which began about two million years back and persisted till 11,000 years back. An “ice age” or, more specifically, “glacial age” is a general geological epoch of long-standing decline in the temperature of the Earth’s surface and environment, ensuing in an occurrence of continental ice sheets, polar ice sheets and alpine glaciers. An ice age is an ecological scheme. In fact, the Ice Age comprised of four phases. During each phase the ice was produced and advanced, after that, melted back towards the North Pole. It is believed this happened four times. The cold periods are called “glaciations”, and the warm periods are called “interglacial” periods. 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 at the start of the Pleistocene (because the Greenland and Antarctic ice sheets still exist).
The earth’s climate has gradually become colder in the last 40 million years. Approximately 35 million years ago the ice cap on Antarctica began to form, and circa 1-2 million years ago the ice cap in Greenland and in Scandinavia and Canada also formed. Even though there has always been a gradual cooling throughout time, the climate has, especially in the northern hemisphere, fluctuated dramatically between periods of great cold (ice ages) and less cold (interglacial period).
The gradual cooling appears to be caused by the continental drift: Antarctica became isolated at the South Pole, the Himalayas were formed and the Isthmus of Panama appeared out of the sea (2 million years ago). With the current configuration of the continents, the earth is apparently susceptible to climate effects through variations in the earth’s orbit around the sun (the so called Milankowich theory). Over the last 40 million years the CO2 level in the atmosphere has fallen from 1000-2000 ppmv to a minimum of 180 ppmv 20.000 years ago. Not since the Perm period circa 250 million years ago has the CO2 level been so low.
In the last 800,000 years, there have been 8 ice ages, each lasting approximately 100,000 years, separated by interglacial periods of between 10,000 and 35.000 years.
Both the hemispheres (and therefore the entire globe) are affected by this ice age cycle. We can also see that the CO2 level varies with the ice ages: When it is cold, there is less CO2, and when it is warmer the level is higher. The CO2 works as an intensifier. Ice cores from both Antarctica and Greenland show that the last ice age started to become milder 19,000 years ago, completely in accordance with increased solar radiation from the earth’s favorable orientation in its orbit around the sun.
We are still in an ice age because, all the ice bergs and ice sheets have not melted. We are coming out of an ice age slowly but surely. But it is faster than we thought, because of all the greenhouse effect that is going on in the world today. (Global warming is making the ice melt quicker).
Most people think of the Ice Age as something that happened so long ago that not a sign of it remains. But did you know that geologists say we are just now reaching the end of the Ice Age? And people who live in Greenland are actually still in the Ice Age as far as they’re concerned.
About 25,000 years ago, any people who may have been living in central North America saw ice and snow the year around. There was a great sheet of ice that stretched from coast to coast, and the ice extended northward without an end. This was the latest Ice Age, and all of Canada, much of the United States and most of northwestern Europe were covered by a sheet of ice over 1000 metres thick.Category: Science