News / Science & Technology

Climate Change Impacts Human Evolution

An artistic rendering of homo erectus killing an elephant on the African savannah about 1.2 million years ago. The adaptability of the human brain has enabled humans to survive and thrive in changing climates. (Smithsonian/Karen Carr Studios)
An artistic rendering of homo erectus killing an elephant on the African savannah about 1.2 million years ago. The adaptability of the human brain has enabled humans to survive and thrive in changing climates. (Smithsonian/Karen Carr Studios)
Adam Phillips
Most scientists agree that the Earth is undergoing significant climate change, partly due to the greenhouse gases produced when fossil fuels like oil, gas and coal are burned.

However, earth scientists know that the planetary environment has always been in flux. Some of those changes have caused extinctions on a massive scale. However, for humans, higher apes and other large mammals, environmental fluctuations have sometimes been a goad to adaptation.

Geologists and climatologists, who specialize in the physical earth sciences, came together with biologists, paleontologists and anthropologists, who mainly concern themselves with life on Earth, for a symposium at Columbia University's Lamont-Doherty Earth Observatory, to discuss the question, “Did Climate Change Shape Human Evolution?”  

“This is a meeting I’ve been trying to have for, I’d say, at least the last 10 years,” says Peter deMenocal, of Columbia University’s Department of Earth and Environmental Sciences, who organized the multi-disciplinary event. “The message from earth’s history is that climate has played a role in every major faunal change event in recorded history. That said, this question of how climate shaped or may have been involved in human evolution is very much an open one we don’t have an answer to. But we’ve got some very intriguing initial clues that point to a strong relationship.”

For example, around two million years ago, the climate in east Africa began to dry, which helped to transform huge wooded areas into the vast open grasslands we call “savannahs” today. Fossil records reveal that large mammals, including our own human ancestors, living in that area also underwent significant physical changes during that time and over the subsequent millennia. Ancestors of antelopes and zebras developed longer teeth with thicker enamel. This enabled these mammals to eat and digest the abrasive grasses that had become a staple of their new diet, deMenocal says.

"The human story is our brains become a lot bigger, our body assumes its very large upright form, our behavior changes," deMenocal says. "For instance, the first appearance of stone tools of any kind comes in at the same time as this drying [of the environment].”

Although the overall environmental trend in Africa between two million and 100,000 years ago was toward dryness, the climate also fluctuated  often between wet and dry. Because humans had developed a brain that could consciously adapt and innovate, they had an enormous survival advantage. When grasses dominated the landscape, they could make a tool to whittle sticks to get to underground tubers. When trees abounded, they could fashion rocks that would crush nuts. When game was plentiful, they could hone a stone that would scrape protein-rich meat off the bones of their prey.

Anthropologist Rick Potts, who directs the Smithsonian’s Human Origins Program, points out that this flexibility was not unique to Homo sapiens. It’s been a feature of all human species, including the now-extinct homo erectus and Homo neanderthalis.  
   
“By the time we get to our own species, the ultimate representation of this picture of plasticity or adaptability is that we have diverse cultures," he says. "Within one species we have almost all the different ways in which people can marry or mate, the ways in which they can organize societies, the kinds of technologies that can be used. We are the first species to think about ‘What if?’ And that is a good response to a world that is very uncertain or conditional.”  

Potts adds that humans’ increasing technological skill at bending nature to our purposes is triggeringing climate changes that might otherwise never have happened. 

“So for example when we manufacture things, we put particulate matter into the atmosphere. We put up gases and things that become smog and that has an effect on the environment that is unintended.”

Those effects, such as global warming, the rise in sea levels and extreme weather events, pose new challenges to our species’ survival. Potts says that traditionally, we have taken two broad-brush approaches to this reality.  We have either pulled back on our growth and ambition, which is hard, or we press on regardless of the long-term impact.

“And so we are really caught between these two visions, and I think the balance between those two visions will determine the history of us on earth.”

Still, Potts and many of his fellow scientists at the symposium on climate change and human evolution express hope that our  awareness of the possibilities of our own extinction will inspire us to imagine and create new ways of living more harmoniously on an ever-changing Earth.

You May Like

China’s Influence Grows With New Infrastructure Bank

Multibillion-dollar China-backed and BRICS-supported Asian Infrastructure Investment Bank seen as possible challenger to such lenders as IMF, World Bank More

Video Rabbi Hits Road to Heal Jewish-Muslim Relations in France

Rabbi Michel Serfaty makes the rounds in his friendship bus to encourage dialogue and break down barriers between the two groups More

Post-deal Iran Leaders Need 'Economic Momentum' to Solidify

Economists say deal could inject more than $100 billion into coffers - not enough to entirely rescue ailing economy - but maybe adequate to create 'economic momentum' More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
US Gay Marriage Ruling Yields Real-life Impacti
X
Michael Bowman
June 28, 2015 10:05 PM
Friday’s landmark Supreme Court decision legalizing same-sex marriage throughout the United States is an outcome few thought possible just years ago, and shows a nation that increasingly tolerates and even celebrates the hopes and aspirations of gay people. VOA’s Michael Bowman spoke to a same-sex couple that will benefit from the high court ruling, and to a Christian scholar who is apprehensive about its potential consequences for America’s faith community.
Video

Video US Gay Marriage Ruling Yields Real-life Impact

Friday’s landmark Supreme Court decision legalizing same-sex marriage throughout the United States is an outcome few thought possible just years ago, and shows a nation that increasingly tolerates and even celebrates the hopes and aspirations of gay people. VOA’s Michael Bowman spoke to a same-sex couple that will benefit from the high court ruling, and to a Christian scholar who is apprehensive about its potential consequences for America’s faith community.
Video

Video Syrians Flee IS Advance in Hasaka

The Syrian government said Monday it has taken back one of several districts in Hasaka overrun by Islamic State militants. But continued fighting elsewhere in the northern city has forced thousands of civilians from their homes. In this report narrated by Bill Rodgers, VOA Kurdish Service reporter Zana Omer describes the scene in Amouda, where some of the displaced are taking refuge.
Video

Video Rabbi Hits Road to Heal Jewish-Muslim Relations in France

France is on high alert after last week's terrorist attack near the city Lyon, just six months after deadly Paris shootings. The attack have added new tensions to relations between French Jews and Muslims. France’s Jewish and Muslim communities also share a common heritage, though, and as far as one French rabbi is concerned, they are destined to be friends. From the Paris suburb of La Courneuve, Lisa Bryant reports about Rabbi Michel Serfaty and his friendship bus.
Video

Video S. Korea Christians Protest Gay Rights Festival

The U.S. Supreme Court decision mandating marriage equality nationwide has energized gay rights supporters around the world. Gay rights remain a highly contentious issue in a key U.S. ally, South Korea, where police did a deft job Sunday of preventing potential clashes between Christian protesters and gay activists. Kurt Achin reports from Seoul.
Video

Video Saudi Leaks Expose ‘Checkbook Diplomacy’ In Battle With Iran

Saudi Arabia’s willingness to wield its oil money on the global diplomatic stage appears to have been laid bare, after the website WikiLeaks published tens of thousands of leaked cables from Riyadh’s Ministry of Foreign Affairs. VOA's Henry Ridgwell reports.
Video

Video Nubians in Kenya Face Land Challenges

East Africa's ethnic Nubians have a rich cultural history that dates back thousands of years, but in Kenya they are facing hardships, including the loss of lands they have lived on for generations. They say the government has reneged on its pledge to award them title deeds for the plots. VOA's Lenny Ruvaga reports.
Video

Video Syrian Refugees Return to Tal Abyad

Syrian refugees in Turkey confirm they left their hometown of Tal Abyad because of intense fighting and coalition airstrikes, not because Kurdish fighters were engaged in ethnic cleansing, as some Turkish officials charged. VOA Kurdish Service reporter Zana Omer, in Tal Abyad, finds that civilians coming back to the town agree, as we hear in this report narrated by Roger Wilkison.
Video

Video Military Experts Question New Russian Tank Capabilities

Russia has been showing off its new tank design – the Armata T-14. Designers claim it is 20 years ahead of current Western designs - and driving it feels like playing a computer game. But military analysts question those assertions, and warn the cost could be too heavy a burden for Russia’s struggling economy. Henry Ridgwell reports.
Video

Video In Kenya, Police Said to Shoot First, Ask Questions Later

An organization that documents torture and extrajudicial killings says Kenyan police were responsible for 1,252 shooting deaths in five cities, including Nairobi, between 2009 and 2014, representing 67 percent of all gun deaths in the areas reviewed. Gabe Joselow has more from Nairobi.
Video

Video In Syrian Crisis, Social Media Offer Small Comforts

Za’atari, a makeshift city in Jordan, may be the only Syrian refugee camp to tweet its activities, in an effort to keep donors motivated as the war in Syria intensifies and the humanitarian crisis deepens. Inside the camp, families say mobile phone applications help hold together families that are physically torn apart. VOA’s Heather Murdock reports.
Video

Video Chemical-Sniffing Technology Fights Australia's Graffiti Vandals

Cities and towns all over the world spend huge amounts of resources battling graffiti writers who deface buildings, public transport vehicles and even monuments. Authorities in Sydney, Australia, hope a new chemical-sniffing technology finally will stop vandals from scribbling on walls in the passenger areas of commuter trains. VOA’s George Putic has more.
Video

Video Cambodia Struggling to Curb Child Labor

Earlier this year a United Nations report found 10 percent of Cambodian children aged 7-14 are working – one of the highest rates in the region – and said one in four children in that age bracket are forced to quit school to help their families. Although the child labor rate has dropped over the past decade, Cambodia has a lot more to do – including keeping more children in school. Robert Carmichael reports for VOA from Phnom Penh.

VOA Blogs