Ice ages their social and natural history

Any geologic era during which huge ice sheets cover vast amounts of land is known as an ice age. Large-scale glaciation can endure millions of years, substantially altering the surface features of entire continents. Throughout Earth’s history, there have been several major ice ages. The earliest known occurred about 570 million years ago during the Precambrian period. The Pleistocene Epoch saw the most recent periods of widespread glaciation (2.6 million to 11,700 years ago).

The Little Ice Age, a more recent glacial period that began in the 16th century and lasted three centuries in Europe and other parts of the world, advanced and withdrew irregularly. It reached its pinnacle in about 1750, when glaciers were more prevalent on Earth than they had been since the last big ice age ended 11,700 years ago.

Ice age influence human history

An ice age occurs when the earth’s temperature is colder than usual, with ice sheets capping the poles and glaciers dominating higher elevations. There are various pulses of colder and warmer climatic conditions within an ice age, called ‘glacials’ and ‘interglacials.’

Prehistoric humans, like other wildlife, were directly impacted by the irregular Quaternary climate. In reality, it appears that the fast shifts in conditions associated with the Ice Age affected human survival and growth; all of the major milestones in our evolutionary history, as well as the emergence of various stone technologies, may be connected to periods of extreme climatic volatility. Humans had to be able to adapt to desert grasslands as well as rainy forests, and those that were capable of doing so clearly outperformed their less capable counterparts. As a result, humans became increasingly resourceful.

Ice Age history

There have been several occasions in Earth’s long history when enormous sheets of ice and snow covered much of the northern hemisphere. Ice ages are the name given to such eras. Huge volumes of slowly moving glacial ice, up to two kilometres thick (one mile), scraped the land like cosmic bulldozers during ice ages. Approximately 97 percent of Canada was covered by ice at the peak of the last glaciation, some 20 000 years ago.

Even if the average daily temperature drops by only a few degrees Celsius for an extended period of time, an ice age can emerge. Colder and warmer periods are common during ice ages. Glaciers and ice sheets build and advance during colder intervals known as glacial eras. (As the snow gets deeper, the lower portion freezes, and the ice sheet’s immense weight causes it to flow across the ground.) Glaciers and ice sheets shrink and retreat during warmer intervals known as interglacial periods.

The Quaternary Period began roughly 2 million years ago and lasts till now. Despite numerous warm periods since then, the existence of at least one big ice sheet—the one over Antarctica—allows us to classify the entire period as one ice age. (The glaciers and the Greenland ice sheet have been around for a long time, but they are more recent.) We are currently experiencing a warm phase, which corresponds to an interglacial period that began roughly 10,000 years ago. The glacial period before that lasted roughly 80 000 years.

There have been at least seven ice ages identified. At least four of them are regarded noteworthy due to the extent of their glaciation or the length of time they lasted:

• from roughly 2 million years ago to now —the Quaternary Ice Age
• Between 350 and 250 million years ago—the Karoo Ice Age
• Approximately 800 to 600 million years ago —the Cryogenian (or Sturtian-Varangian) Ice Age
• Approximately 2400 to 2100 million years ago —the Huronian Ice Age.

Pleistocene ice age

The Pleistocene epoch encompasses the last ice age, during which glaciers blanketed vast swaths of the planet. According to the International Commission on Stratigraphy, the Pleistocene era, or simply the Pleistocene, began about 2.6 million years ago and ended 11,700 years ago.

According to the University of California Museum of Palaeontology, modern humans, or Homo sapiens, emerged during the Pleistocene and expanded across most of the Earth before the period ended. Many ice age giants, such as woolly mammoths (Mammuthus primigenius) and sabre-toothed cats, lived throughout the Pleistocene, but many died out in a mass extinction event at the end of the period.

The Pleistocene epoch was preceded by the Pliocene epoch and succeeded by the Holocene epoch, which we are still living in today, and is part of the Quaternary period (2.6 million years ago to present). According to Collins Dictionary, the name “Pleistocene” is a Latin mixture of two Greek words: “pleistos” (meaning “most”) and “cene,” which comes from “kainos” (meaning “new” or “recent”).

Causes of the Pleistocene Ice age

Scientists are still studying how ice ages occur, but we do know that they are triggered by a number of factors, including shifting carbon dioxide levels, Earth’s position in the solar system, and the amount of heat our planet receives from the sun, as previously reported by Live Science. The shape of Earth’s orbit, for example, changes every 96,000 years, and the planet is cooler when Jupiter’s gravity pulls it further from the sun.

For the past 50 million years, the planet has been cooling. The Isthmus of Panama land bridge connecting North and South America created about 4.5 million years ago, possibly triggering the last cold age. The Atlantic and Pacific oceans could no longer interchange tropical water, sending warm water northward and increasing precipitation, which fell as snow in the Northern Hemisphere. As a result of the snowfall, glaciers and ice sheets formed, blocking sunlight and maintaining Earth’s cooling trend.

Conclusion

Ice ages are periods of time when glaciers and large ice fields cover large areas of the Earth’s surface. Depending on how long an ice age lasts, scientists will employ more specific terminology. According to geologic data, Earth has experienced seven significant periods of cooling and ice accumulation throughout its history. These times are known as ice eras and, with the exception of the last, are poorly understood.