Three papers published in Science on March 15th may cause scientists to re-write at least part of the story of the emergence of Homo sapiens - our species. These new studies suggest five important surprises – two of which could represent very unexpected things about climate change.
The research was conducted by paleontologists and other scientists in the Olorgesaillie region of Kenya, much of it sponsored by the Smithsonian's Human Origins Program. Lots of previous research has been done there, probably most famously by paleontologists Louis and Mary Leakey.
Let's consider each surprise.
Surprise #1: Evidence of sophisticated tools and trade
Earlier research at Olorgesaillie suggests evidence of human-like species as far back as 1.2 million years ago. These weren't Homo sapiens – our species – but were pre-cursor species such as Homo erectus, Homo heidelbergensis, and Australopithecus. One of the most famous paleontological finds was Lucy, a member of the Australopithecus species. Lucy was a female of that species who lived about 3.2 million years ago in what is now Ethiopia.
The scientists at Olorgesailie discovered a range of fairly sophisticated tools, many made out of obsidian. Scientific dating indicates the tools were created roughly 320,000 years ago. Previously, scientists had observed the creation of very large, crude tools. Up to now, any such more sophisticated tools scientists had found had dates less than 280,000 years old.
That was surprising enough, but perhaps the bigger surprise was the fact that many were made of obsidian. At one Olorgesailie site, 46 percent of more than 3,400 stone artifiacts were obsidian. Some of the finds indicate signs of having been attached to handles, likely spearpoints, according to the researchers.
So why was the presence of obsidian so significant? It's because there is no obsidian in the area where the tools were excavated. However, analysis of the chemical composition of the obsidian suggests that it could have come from an area 25 to 50 kilometers away. That means the toolmakers would have had to transport the obsidian over a fair distance. Not what we moderns consider a great distance, but certainly a great distance for 300,000+ years ago. That meant that they traveled over relatively long distances, most likely in search of food. In the course of foraging, they encountered other hominids and undertook trade with them.
Surprise #2: These early groups were using dyes
The researchers also discovered a total of 88 pigment lumps, including two pieces with grinding marks, that came from an indeterminate distance outside Olorgesailie. The reason this is significant is that pigment might have been applied to one's body or belongings, and that may have provided evidence of group identity or social status, according to the researchers.
Rick Potts, from the Smithsonian Human Origins Project, and one of the lead researchers on the project, observed, "We don't know what the coloring was used on, but coloring is often taken by archeologists as the root of complex symbolic communication." He went on to say, "Just as color is used today in clothing or flags to express identity, these pigments may have helped people communicate membership in alliances and maintain ties with distant groups."
Surprise #3: Evidence of the emergence of human society earlier than expected
When did human society first emerge? Up until now, the evidence has suggested the first signs of what we call society appeared about 100,000 years ago. That conclusion was based upon evidence such as cave paintings found in Ethiopia. So while Homo sapiens may well have emerged 250,000 to 300,000 years ago, scientists have felt that societies didn't emerge until 100,000 years ago.
When you consider the new evidence from Olorgesailie, that probably needs to be reconsidered. The evidence from these latest studies includes more sophisticated tools, trade, and dyes, and suggests some form of human society 200,000 years earlier than previously thought!
In short, what the Olorgesailie researchers found was definitely a surprise. According to a press statement issued by the researchers, "The obsidian transport and the collection and processing of pigments imply an early development of social networks connecting members of our species across longer distances… This practice is characteristic of our species, but in contrast to our closest primate relatives, and is not implied by the material record of the preceding early Stone Age levels at Olorgesailie," said George Washington University paleoanthropologist Alison Brooks, a senior member of the Olorgasailie team, in an interview with Discover.
After all, chimpanzees and other non-human primates don't travel into one another's territory. If they do, they'll like end up in a fight to the death. So the Homo species that occupied Olorgasailie 300,000 years ago must have developed a higher level of sophistication.
Rick Potts, the Smithsonian researcher, argues that "greater mobility of these groups encouraged inventive thinking about how to acquire resources."
Surprise #4: Climate change may have helped Homo sapiens
But why the shift away from clunky, durable hand axes used by these early hoinids? Can the emergence of more sophisticated tools be explained? The researchers offer a possible explanation. "One of the things we see is that around 500,000 years ago in the rift valley of southern Kenya, all hell breaks loose. There's faulting that occurs, and earthquake activity was moving the landscape up and down. The climate record shows there is a stronger degree of oscillation between wet and dry. That would have disrupted the predictability of food and water, for those early people," Potts says. "It's exactly under those conditions that almost any organism—but especially a hunter-gatherer human, even an early one—would begin to expand geography of obtaining food or obtaining resources. It's under those conditions that you begin to run into other groups of hominins and you become aware of resources beyond your usual boundaries.
The evidence suggests there was dramatic change in wet and dry conditions in the area of Olorgesailie around 320,000 years ago. Moreover, these changes appear to have occurred over decades, not thousands or hundreds of thousands of years.
The Olorgesailie researchers don't know whether the tools and dyes they found were from a Homo sapien population, as there were no remains located. However, other evidence suggests this is when Homo sapiens first emerged as a species. So we can't tell if it was Homo sapiens or one of the earlier Hominid species. But according to the Olorgesailie researchers, rapid climate change could well have been the reason the population started foraging over larger areas with ever smaller, more sophisticated tools. This would have brought them into contact with other groups. At some point they started trading with these other groups, the reason they probably first acquired obsidian.
These interactions probably came through necessity. Like today, natural disasters posed challenges beyond the scope of the individual. Earthquakes and changing seasons and climates likely offered proof to early humanity that it was better to work together. "This change to a very sophisticated set of behaviors that involved greater mental abilities and more complex social lives may have been the leading edge that distinguished our lineage from other early humans," says Rick Potts, in a press statement.
Would they have started foraging over wider areas if the climate had been stable? Why work harder than you need to, especially if by crossing territory you end up encountering other groups? No doubt, such widespread foraging would have been dangerous – just as its dangerous for a non-human primate to cross into another's territory. Why do something dangerous … unless you need food?
Likely, that's why these populations started moving, and encountering other groups.
Homo sapiens was more sophisticated than the other hominids and eventually became the only hominid species.
So in a peculiar sense, perhaps we humans can thank climate change for our triumph over the other hominids? Well, that's the conclusion of Rick Potts, the researcher from the Smithsonian.
Surprise #5: We might actually look forward to dramatic climate change
In a funny sense, climate change has been good to our species. After all, perhaps the biggest climate change event of all time – the asteroid collision 66 million years ago – led to the demise of the dinosaurs and the triumph of mammals. Had that not occurred, the dominant species today might still be dinosaurs. After all, the event occurred a mere 66 million years ago.
As previously noted, the evidence from Olorgesailie suggests rapid climate change may have been the spur to the hominid population to forage over wider areas, as well as develop more sophisticated tools. While we don't have proof, there's a very good chance the Olorgesailie population were Homo sapiens. However, even if they weren't, the observed behavior is consistent with what we know about our species. Given a difficult situation, Homo sapiens becomes more creative and inventive, as well as more mobile.
We're facing another time of potentially very rapid climate change. The evidence seems pretty clear that if we don't take quick action, our climate will rapidly change.
Which leads to an unexpected possibility: based upon our past experience, rapid climate change might be awful for other species, but it could be great for us! That's because when Homo sapiens encounters big problems, we tend to become quite resourceful and inventive. Facing rapid climate change, we might see an outpouring of creativity.
You can make the argument that we've already seen that. After all, we've only very recently realized there was a serious climate change risk, yet in short order, our species has developed entirely new technologies for solar, wind, and batteries, for example. Absent the threat of climate change, would change have occurred so rapidly? It's hard to say, but there does seem to be plenty of evidence that humans become more creative when they're put under stress.
Please understand, I'm not suggesting we encourage more destructive climate change. It's a real problem that should be solved – quickly. But even if disaster strikes, and traumatic climate change occurs, in a most peculiar, and unexpected, way it actually might benefit humans.
