Sometime between 75,000 and 70,000 years ago, a terrific volcanic eruption occurred on the island of Sumatra in Indonesia. Plumes of volcanic dust from the eruption were 5 miles high and fell as far west as India. Volcanic dust blocked the rays of the sun and earth was plunged into an ice age. So much of earth’s water was trapped in ice that deserts spread across northern Africa, trapping Homo sapiens in central and southern regions of the continent.
At about the same time the deserts were growing, 75,000 years ago, sea levels were dropping. As their population expanded, those Homo sapiens in the coastal fishing culture began to look across the narrow strait at the south end of the Red Sea. Across the strait lay the green hills of Yemen. An adventurous group decided to cross the Red Sea. How many they were and how many were lost in the crossing is not known. However, that they crossed is known. In 2003 Discovery Channel told this story, The Real Eve.
While the fishing peoples were traveling east, the ice that had covered Eurasia began to melt. As it did, the Sahara became a savannah that lured mammals into it. Following herds through that gateway, Homo sapiens of the hunting culture first peopled the Ancient Near East and then Central Asia, and the Mediterranean region.
Another ice age began 40,000 years ago and as deserts returned, the Saharan gateway once again closed. Migrations continued north of the Sahara as Homo sapiens encountered hominins (Neanderthals and Denisivans) and learned to adjust to colder climates. Meanwhile migrations along the coasts continued. By the time hunters and gatherers were expanding their populations inland, coastal migrants had fished all the way to Asia and populated Australia.
Continuing Migrations
By 20,000 to 15,000 years ago, people from Central and Northern Asia had made their way across Beringia, what we know today as the Bering Straits. At that time ice made it into a land bridge. Some people came by land and some by boat down into the Americas. By the time the ice began to melt 15,000 years ago, human beings had reached the tip of South America.
The last big migration was 3500 to 2500 years ago. People from Taiwan, the Philippines, and Papua New Guinea expanded into the islands of Polynesia to form what is known as Oceania. As Spencer Wells, director of National Geographic’s Genographic project says, “Our history is written in our blood.” We are one global family, a migratory people with relatives in every corner of planet earth.