Climate change in South Africa during ancient times may have been a driving force behind advancements in human culture and tool-making, according to new research.
South Africa's climate became much wetter 80,000 years ago, and wildlife and plant life flourished, just as surrounding areas became drier, killing off many of the natural food sources that had previously existed in the region. The climate trigger was the last ice age, which caused the ocean currents to slow, and cold air to dominate over areas north of the region. This denser, colder air blocked the region of warm air, trapping it over South Africa.
Evidence for this change was revealed to researchers through the examination of a sediment core collected of the South African coast, showing climatic conditions there for the last 100,000 years. This transformation in climate 80,000 years ago may have spurned growth in culture and toolmaking between 60 and 70,000 years ago.
Martin Ziegler, a Cardiff University Earth science researcher who announced the findings in the journal Nature Communications, said, "We provide, for the first time, really good evidence that the occurrence and disappearance of these first finds of human innovation are linked to climate change."
As the average long-term weather became drier in locales surrounding the region, vegetation there began to disappear. The conditions in what is today South Africa, meanwhile, were becoming even more lush and plentiful. This drove the people of other regions into the area, increasing human competition and cross-breeding. The people living there then developed more advanced tools and began writing on walls as a means of communication. It was during this era that the people of that region first began to create complex stone tools and wear shell jewelry, as well as develop the first complex trade networks.
"Those dense populations are forming networks over the landscape which is no longer huge patches of arid land that they cannot cross," said Chris Stringer, who is a co-author of the study from London's Natural History Museum. "They are connecting with other populations and lo and behold... we get these cultural innovations."
These events occurred during the Middle Stone Age, which began 280,000 years ago and ended approximately 40,000 years before our time.