We all know that current climate change (aka global warming) is human-induced, specifically from activities that began during the Industrial Revolution in the 18th and 19th centuries. You’ve probably heard scientists (and Bill Nye) say that the changes we’ve seen are “unprecedented” — and that the increase in atmospheric carbon dioxide from the Industrial Revolution is to blame.
A new study led by Nicole Boivin (heyyy lady scientist!) at the Max Planck Institute for the Science of Human History provides evidence for long-term human influence on the environment. Using tons of data from the fossil record, stable isotope analysis, and ancient DNA, the team looked at relationships between species extinctions and human activity. They found that the movement of modern humans (Homo sapiens) out of Africa is actually associated with A LOT of species extinctions. This evidence, the authors argue, might be a necessary framework to apply to our current conservation efforts.
The fossil record shows that modern humans left Africa around 100,000 years ago. By 12,000 years ago, we had reached the Americas. As we moved around the globe during this time, we constructed our habitats by disrupting the ecosystems that already existed — unfortunately sometimes leading to species extinctions.
Between 50,000 to 10,000 years ago, two-thirds of ~150 species of megafauna (big animals) went extinct because of an increase in human populations, according to the study. Two-thirds!! We completely wiped out like 100 of those species.
So what were we doing that led to all this destruction?
Our movement brought fire, deforestation, and new predatory threats. As our population grew, agriculture and domestication of animals spread. We hunted.. and over-hunted. We began altering the environment even more by cultivating land, changing landscapes, and introducing new, non-native crops. This information isn’t new – tons of studies outline the effects we’ve had on the environments we’ve encountered.
But by providing archaeological data on our impact on the environment, from 100,000 years ago to present, Dr. Nicole Boivin and her team hope to shift the focus of conservation efforts to consider how deep our history of environmental disruption goes. It’s like there are no landscapes left untouched by human activity and destruction, especially considering species closely related to humans (like Homo erectus) also migrated out of Africa — millions of years ago! That’s a pretty long time to be wreaking havoc.
Observed climate change in the past 60 years has been particularly drastic. Increased carbon dioxide in the oceans, higher temperatures, more extreme weather — these are only a few, broad changes we’ve witnessed. Maybe these intense, long-term patterns are the result of a very long history of environmental change by humans… like, thousands and thousands of years of history.
And maybe they aren’t.
But hopefully we can start to use our evolutionary history to better understand how to prevent extinctions and keep the planet safe for the future. And as the human population continues to grow and move around, let’s try to remember that we have the technology and knowledge to stop being the worst and screwing things up.