Ice Age continues to be an intriguing phase in the history of mankind with its causes being debated worldwide. But what exactly is Ice Age? It is a long interval of time, ranging from millions to tens of millions of years, when global temperatures fluctuated, with large areas of the Earth covered by continental ice sheets and alpine glaciers. During the last 2.6 million years, there have been five documented ice ages: the Huronian, Cryogenian, Andean-Saharan, Karoo Ice Age and the Quaternary glaciation. The recent glacial period in human experience (often referred to as the Ice Age), took place during the concluding years of the Pleistocene- which originated 1.8 million years ago and concluded 11,700 years ago.
As mentioned, scientists have not been able to decipher the exact causes behind this. However, they consider that the fluctuations in the amount of incoming solar radiation, that is, insolation and the changing positions of constantly moving continents, which affect ocean and atmospheric circulation patterns, are some of the key factors. Initially, Serbian scientist, Milutin Milankovitch in 1938 explained Earth’s long-term climate fluctuations caused by Earth’s ever changing position as compared to the Sun. This is now known as Milankovitch cycles. This cycle explained that the ice ages that occurred in the geological past of the Earth, as well as the climate changes on the Earth, can be expected in the future.
In 2009, researchers from Oregon State University and other institutions pointed out the slight shifts in solar radiation caused by predictable transition in Earth’s rotation and axis in the Science journal. These shifts caused global ice levels to reach their peak about 26,000 years ago, stabilize for 7,000 years and then begin melting 19,000 years ago, eventually bringing closure to the last ice age.
It was Louis Agassiz, Harvard University professor, who proposed the subjugation of Ice Age on Earth. He put forward the theory that the rocks that dot New England’s landscape were shaped and deposited by glaciers. According to him, the erratic large boulder was left by a glacier; however, this theory was rebuked by his colleagues. His theory was proved correct to a certain extent because of the granite composition in a glacier, a rock that one will not find in that area.
But the term ‘ice age’ was coined by German botanist, Karl Friedrich Schimper. His fieldwork in the Bavarian Alps made him conclude that ice is the means of transport for the boulders in the alpine upland. He also proposed that there must have been global times of obliteration with a cold climate and frozen water.
There was also a time when the whole earth was covered in ice. Scientists have named this phenomenon as Snowball earth which signifies the coldest global climate imaginable. It is assumed that if any such thing happens the whole earth would be covered in ice and the global temperature would drop to
–50° C. The drop in temperature would be caused as solar radiation would be reflected back to the space by the icy surface.
There lies another pertinent question about ice age. Did human beings exist during this time ? Surprisingly, yes, there were three species of human beings during this epoch. First, Homo Erectus, who had been around for 1.8 million years, even survived the previous ice ages, but got extinct around 70,000 years back. Second, Neanderthals, who had been around for 3,50,000 years but with the disappearance of the giant ice sheets, the last communities of the Neanderthals died in Gibralter. Finally, modern man evolved around 200,000 years ago. The modern man commenced on an unprecedented level of cultural and technical achievement in a short period of time.
Now let’s talk about the climate during the ice age. Due to the harsh cold, people living in that age used animal skin to prepare their clothes and build their homes out of bones. It has been found that even centuries ago, they were quiet modern. They burrowed in ice to store food and designed sophisticated tools. Their food was cooked and not raw. They buried their dead and also painted their caves. For obtaining meat for consumption, they either trapped and killed the animals or drove them off the cliffs. As far as the flora goes, land was mainly bare apart from a little vegetation that could withstand the freezing cold. Signs of such herbs, shrubs and trees are still visible in Asia, North America and Europe.
The fauna found during the ice age were gigantic. The wolf like carnivorous, Andrewsarchus was around 13-feet long. Baluchitherium, the largest land mammal, was a hornless rhinoceros found during this era. Another species that was found during this age was the cave lion around 25% bigger than that found in the present times.
Mammoths evolved for about 1.5 million years, adjusting to the unstable climatic condition during the ice age. With each cycle of glaciation and deglaciation, habitats had to go through the process of disruption settlement and again disruption. The glaciers were formed with the amalgamation of ice to form thick continental glaciers, which at times in their flow crushed the standing forests.
With so much attention on global warming, the prospect of ice age has been all but forgotten. However, in the given circumstances, the catastrophe of ice age would know no bounds. Due to the greenhouse effect, carbon dioxide in the atmosphere neither allows the sunlight to penetrate nor the infra-red rays to escape the atmosphere. Although scientists today, have not left any stone unturned to tell us about the importance of growing temperature of the earth, this might not be sufficient to avert the destined.
We need to be aware of similar repercussions that our earth might have to face if we do not deal with the climate change situation effectively. It may not only lead to an unpredictable crisis in the food, water, energy and medical supply chains but could also lead to failure in the state machinery, cause famines, flood or disease could lead to international or internal conflicts. It’s better late than never to initiate efforts that may not lead to any untoward consequences that our human beings have faced earlier in the ice age and are shadowed by the same even now.
This Article is taken from Disha’s The Knowledge Book.
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