Climate History: Exploring Climate Events and Human Development
The Past 100,000 Years
Did Climate Challenge the Creativity of Early Homo sapiens?

As scientists inquire into climate change and the development of humanity during the past 100,000 years, there are many questions that have yet to be proven to the full satisfaction of the scientific community, many uncertainties relating to the human dimension of climate change.

For example, were early Homo sapiens challenged by abrupt climate change in the form of volcanic winter that lasted for many years? That is what Stanley H. Ambrose and some of his colleagues suspect may have happened during a critical time in human development. What is known is that some 71,000 years ago, an eruption of Mount Toba on the present day Indonesian island of Sumatra, spewed some 2,800 km³ of material into the atmosphere. This compares with less than 1 km³ from Mount St. Helens (Rose, 1987). Ambrose suggests that this event could have thrown the planet into a six year volcanic winter and 1000 year instant ice age which could have reduced human populations, causing population bottlenecks that accelerated the differentiation of isolated human populations and encouraged increased cooperation within tribal groups for survival (Ambrose, 1998) and Rampino, 2000). Image above is of Mount St. Helens, March, 1980 by USGS.

It is also known from recent excavations by Chris Henshilwood and others in the Blombos Cave in South Africa that over 70,000 years ago people inhabiting the cave near the tip of the African continent lived a fairly sophisticated and advanced lifestyle (Henshilwood, 2002 ).

Making stone and finely hewn bone tools, living on game animals as well as sea food, these Homo sapiens had the same anatomy and brain size as modern humans. They carved abstract symbols and may have painted their bodies red for rituals. Tools had been developed tools for fishing and their delicate bone awls may have been used for leather working. Their lifestyle, in fact, was very similar to that of people who inhabited the same cave only 2,000 years ago.

This discovery is an important one, for it suggests that modern human behavior developed in Africa at a much earlier stage than previously thought. Archaeological evidence had until recently a more "eurocentric" focus built around the theory that modern human behavior developed later in Europe, where numerous site dating to around 40,000 years ago have been excavated. Some theorized it was the harsh climate that forced Homo sapiens to become more creative in order to survive, but the new discoveries suggest advances were made prior to the last Ice Age in Europe.

Prior to this discovery, it was assumed that 40,000 years ago, with much of the northern hemisphere blanketed by glaciers and ice, a "cultural explosion" occurred as evidenced by a wide pallet of stone tools and jewelry made by Homo sapiens in Europe .They expressed their creativity through paintings, including the famous cave paintings from the Vallon-Pont-d'Arc cave in France that date to between 30,000 and 32,000 years before the present. This cave was discovered in 1994 and contains over 300 images of bear, mammoth, horse, woolly rhinoceros,lion, stag, ibex, wild ox and other animals which existed in Europe at the time. (Many of these animals became rare or extinct at the end of the last Ice Age, and some theorize it was because they were over-hunted by humans. See Resources 100,000 years.)

The new findings suggest that prior to coming to Europe, Homo sapiens had developed "modern" behavior. It would still be a number of generations, however, for other major advances to be made such as the formation of villages, which developed in the post-glacial period around 13,000 years ago, and the domestication of crops, which began around 9,000 years ago according to current theories. While early man may have inhabited the Americas 30,000 years before present, the earliest accepted sites, located in in New Mexico and Arizona, are radiocarbon dated at 11,500 to 11,200 years B.P.(Grayson, 1993).

For more on the excavations at Blombos Cave visit the Cape Field School. Photos of Blombos cave and artifacts courtesy of C. S. Henshilwood.

Additional cave art photos from the French government's Great Archeological Sites.