In the last installment of this series titled The Modern Human, we explored a few theories on how the modern day human came to be the only surviving hominine species on the planet.
Around 15,000 years ago, humankind colonised North America by migrating through the Bering Strait which was then a long stretch of land connecting modern day Russia to Alaska. The humans then started drifting southwards as the ice melted and by around 12,000 years ago, mankind had reached the southern-most tip of South America.
By 10,000 years ago, we had colonised almost whole of the habitable world. Migration lasting for thousands and thousands of miles was made possible by the Ice Age which allowed humankind to walk across the imposing and deadly oceans that grace our world.
A Frozen World
An Ice Age is a period of time that could last for a few thousand to hundreds of millions of years in which global temperatures drop significantly below freezing point resulting in polar ice caps expansion. These periods are interspersed with interglacial intervals – regular warming periods of around 10,000 years. In the last 800,000 years, scientists have recorded five major ice ages in our planet’s history:
- Huronian: 2.4-2.1 billion years ago
- Cryogenian: 850-635 million years ago
- Andean-Saharan: 460-430 million years ago
- Karoo: 360-260 million years ago
- Quaternary: 2.6 million years ago-present
The current glaciation period which is simply being called “Ice Age” and reached its peak around 18,000 years ago. The interglacial period began 11,700 years ago.
The Ice Age was a time of unimaginable cold away from the equator. The Arctic ice cap expanded towards the northern hemisphere turning it into a frozen waste. With so much of Earth’s water now frozen, sea levels saw a drop of 500 feet. As the ocean waters dropped, long submerged swathes of rocky lands emerged out of the water, bridging tiny islands to large continents.
The equatorial lands faced a different predicament altogether. The freezing of water bodies induced a decline in seasonal rainfall. This resulted in the turning of most land areas between the tropics into deserts.
As the ice spread further into the southern reaches of the northern hemisphere, the flora and fauna were drawn to the warmer latitudes. As the ice melted, they moved northwards again. Humankind survived these harsh conditions by mastering the art of harnessing fire, inventing the concept of clothing and developing new social skills.
The last Ice Age reached its zenith in around 20,000 years ago. The northern hemisphere was coated in ice sheets and the tropical lands were painted green by the savannahs, steppes and prairies. These lands which were rich in seasonal grasses they provided fodder for large herd animals like bison, horses, mammoths and reindeer.
These animals were important food sources for the early humans. As mentioned earlier, North American lands were invaded around 15,000 years ago. During that time, the rolling grasslands catered to some mighty animals. The giant bison had a horn that stretched six foot across the two sides of his head. Then there were the casteroides or giant beavers. Big cats the size of lions sprawled across the grass. Even mastodons and mammoths graced these parts of the world.
But nearly all were extinct about 10,000 years ago as a result of hunting. Even the horse – an animal that was in abundance in North America became nearly extinct until Christopher Columbus and all the other voyagers who landed on the shores at his wake reintroduced the four-legged animal to the New World.
While these grasslands prospered with animals and vegetation, the lands south of Eurasia – the area surrounding the Sahara, the Middle East and parts of the Indian subcontinent became arid. The population of these parts found solace along water bodies like the Nile.
In Western Europe, modern humans replaced the Neanderthals who were on the brink of extinction. The age of expression commenced with several cave paintings, drawings and symbolic inscriptions found in southwest France, the Pyrenees and northern Spain.
Around 12,000 years ago, as the Ice Age was drawing to a close, vegetation and animal kingdoms covered the grey wastes of the northern hemisphere. By 10,000 BC people were investing their time and energy into finding new ways to produce food. This was the first step towards agriculture and irrigation.