Scientists at Hull University study how climate change affects early human migration.

Dr Jonathan Dean, a scientist from Hull University, joined an international expert group to explore how climate change affects human migration on the earth.

Our species Homo sapiens is thought to have evolved in East Africa 200,000 years ago.

The reconstruction work has now shown how the climate in East Africa has evolved in the past 200,000 years, which may enable human beings to migrate from the African continent to all parts of the earth.

A group of scientists, including Dr Dean, studied hundreds of meters of sediment cores drilled on a lake bed named Chew Bahir in southern Ethiopia.

Then they can calculate how the climate changes with time.

Dr Dean said: "We have always wanted to know how the climate evolved during Homo sapiens, so that we can find out whether climate change will affect the course of human history."

"But until recently, there was no record of climate change that spanned our entire human history. Our long-term record of climate change has been formed for many years. "

"While working at Hull University, I collaborated with the British Geological Survey to analyze some data of this study."

The research team found that from 200,000 years ago to 6.5438+0.25 million years ago, the climate in East Africa was relatively humid, and the precipitation was at least 20-30% more than that in this area today, which means that the condition of having enough food and water was beneficial to early humans.

Further research shows that other parts of Africa are in a humid state at this time. Under such conditions, human beings can cross Africa relatively easily. Some people even ventured out of Africa to Arabia, which they did 654.38 million years ago.

However, these fearless humans seem to have become extinct before they spread further.

Then, from 6.5438+0.25 million years ago, the climate in East Africa gradually dried up. This long-term drying trend was interrupted by short-term climate change that lasted for thousands of years.

These are all related to the changes in the North Atlantic circulation, which shows how changes in one part of the world affect the climate in another.

One of the short-lived climate changes occurred in the wet period 62,000-60,000 years ago.

This is roughly consistent with the phenomenon that Homo sapiens "successfully" migrated from Africa to other parts of the world.

This rainy season will provide enough food and water resources for human beings and make the migration in Africa possible.

In the past 60 thousand years, the environment has become more and more challenging for people who have stayed in East Africa.

Some particularly dry areas, such as Chew Bahir, are even completely dry. At these times, humans have to seek refuge in high-altitude areas of Ethiopia, where they can still get enough food and water.