Record-breaking simulation shows how climate has shaped human migration
The model suggests that changes in meteorological models in South Africa may have contributed to the rise of Homo sapiens.
A colossal simulation of Earth's climate over the past two million years provides evidence that temperature also other planetary conditions influenced early human migration - and likely contributed to the emergence of modern humans around 300,000 years ago.
The discovery is one of many to emerge from the most significant model studying how changes in Earth's motion have affected climate and human evolution, published today in Nature1.
The idea that climate may have changed an essential role in human evolution dates back to the 1920s,2, when scientists began discussing whether drier conditions prompted early human ancestors to walk on two legs to adapt to life in adapting to the savanna. So far, however, researchers have struggled to provide convincing evidence that climate played a role in shaping humankind.
Orbital Effect
In the new study, Axel Timmerman, a climate physicist at South Busan National University in South Korea, and colleagues ran a supercomputer climate model for six months to reconstruct how past temperatures and precipitation might affect the resources available to humans. Several million years. In particular, researchers have studied how long-term climate variability caused by Earth's astronomical movements can create conditions to stimulate human evolution.
The expulsion and attraction of other planets alter Earth's climate by changing the tilt of the planets and the shape of their orbits. For example, in a 41,000-year cycle, the Earth's tilt varies, affecting the intensity of the seasons also changing the amount of rain that falls in the tropics. And in a 100,000-year cycle, Earth moves from a circular orbit — which brings more sunlight and a more extended summer — to a more elliptical orbit, which reduces sunlight and can lead to periods of glacial formation.
Timmerman and colleagues used simulations that included these astronomical changes, then combined the results with thousands of fossils and other archaeological evidence to determine where and when six human species — including early Homo erectus and modern Homo sapiens — could have lived.
movement and mixing
The study yielded a surprising amount of data, and Timmerman says some attractive models have emerged. For example, the researchers' analysis shows that the ancient human species, Homo heidelbergensis, began expanding its range about 700,000 years ago. Some scientists believe this species may have given birth to many other species worldwide, including Neanderthals (Homo neanderthalensis) in Eurasia and H. sapiens somewhere in Africa.