how did the changing environment affect the life of early people around 12000 years ago
Answers
Previous major global climate changes were glacial cycles that happened long before human civilization developed.
The human species evolved during the last 2.5 million years. Our far distant ancestors survived through multiple gradual cycles of cold ice ages, but did not experience any previous "hot ages."
We homo sapiens in our current form appeared only about 200,000 years ago. So our species has survived two ice ages. In each ice age global temperatures were colder by 4 °C. The warmest period ever experienced by early humans was about 1 °C warmer (global average) than today. That period occured between the two most recent ice ages, 120,000 years ago (Eemian). Over the next 100,000 years temperatures gradually decreased into a new ice age. During that colder period humans began to expand out of Africa and across the globe. Ever since the Eemian much cooler temperatures have been the norm.
Climate has affected human life and civilization from the emergence of hominins to the present day. These historical impacts of climate change can improve human life and cause societies to flourish, or can be instrumental in civilization's societal collapse.
Answer:
climate change, habitat destruction, extinctions — the Earth has seen it all before, thousands of years ago. And humans may have been partly to blame for many of those changes in nature, too.
A new study published Friday in Science Advances shows that the arrival of humans in Patagonia, combined with a changing climate, led to the extinction of many species of megafauna about 12,000 years ago in the southern portion of what is now South America. The research offers a significant moment in the natural history of the continent: a definitive date of the mass extinction of megafauna — large or giant animals, like mammoths and giant sloths — in this part of the world. It also suggests a potential relationship between threatened species and climate change in our own time.
The authors of the study from the University of Adelaide in Australia, with help from scientists from South America and elsewhere, found that the presence of humans in Patagonia was not enough to drive extinction, but the one-two punch of humans and a warmer climate led to the collapse of many species.
The scientists sequenced the mitochondrial DNA from 89 megafaunal bone and teeth samples that had been excavated from caves and rock shelters in Patagonia. They were able to date 71 of those samples, and then looked into whether the extinctions of those species were associated with other known events — ice ages or warming periods, for example — in the annals of either climate change or human existence.
Humans had been in Patagonia for at least 1,000 years before this mass extinction, and they overlapped with megafauna during a cold period known as the Antarctic Cold Reversal. After that climatic period, a rapid warming phase followed, and much of the ice that carpeted the region began to melt, allowing for a beech tree forest to creep across the land, reducing their original habitat.