Did Humans Cause the Global Extinctions of Mammals?

Cursed is the ground because of you.
— Genesis 3:17

Humans cause a lot of damage to the environment. Understandably, many people attribute the destruction to the ballooning human population and the activities associated with advancing and sustaining first world economies and industrializing the nations of the second and third worlds. It’s tempting to think we could mitigate our destructive impact if we reduced our numbers, gave more consideration to managing limited resources, and perhaps even returned to simpler ways of life.

But new research indicates that the human-caused damage may be due to something other than the quest for better lives—it may be due to something intrinsic to human nature. The report shows that as humans migrated (starting about 50,000 to 70,000 years ago) from Africa and into Asia, Australia, Europe, and the Americas, they precipitated the wide-scale extinction of large mammals and, thus presaged the anthropogenic destruction of the environment witnessed today.1

Prior to this study, scientists debated the cause of the late Quaternary’s global megafauna extinctions. Some argued it was due to the climate change associated with the last Ice Age. Others maintained that modern humans caused the loss of large-bodied mammals either directly through overhunting or indirectly through environmental ruin.

The recent analysis utilizes the most comprehensive and detailed data set for global extinctions and climate variation ever used. The extensive data set allowed the researchers to unequivocally demonstrate that human migrations into Australia and the Americas led to the catastrophic loss of large-bodied mammals in these continents.

However, the researchers detected only limited loss of mammals in Africa, the location of humanity’s origin. And in Eurasia the trigger of extinction is much less clear, though it appears that climate change, not humans, was the primary cause. The researchers note that hominids (such as Homo erectus and Neanderthals) populated Africa and, to some degree, Eurasia prior to the arrival of modern humans. They argue the long-term exposure (and co-adaptation) of large-bodied mammals to hominids prepared these animals to co-exist with modern humans. On the other hand, the mammals of Australia and the Americas were not afforded the same opportunity.

It is remarkable to think of the devastation caused by the first humans as they made their way into new regions throughout the world. And, yet, it appears that human population sizes had little to do with it. Genetic variability data indicate the first wave of human migrations consisted of relatively small groups. It seems that even in limited numbers, humans possess an innate capacity to wreak havoc on a grand scale.

These insights make sense in light of the biblical account of human origins. Scripture teaches that God created human beings in his image (Genesis 1:26–27). God designated us as His representatives on Earth and charged us with the responsibility of serving as stewards of the planet (Genesis 1:28–29). But then humanity rebelled against God—our relationship with our Creator was damaged and the imago Deimarred (Genesis 3:1–13). Consequently, we can no longer effectively serve as caretakers of the planet.

Scripture goes as far as to state that the ground is “cursed” because of human sin (Genesis 3:17). And it appears this has been the case from the days of prehistoric hunter-gatherers through the present age of oil spills and landfills.

  1. Christopher Sandom et al., “Global Late Quaternary Megafauna Extinctions Linked to Humans, Not Climate Change” Proceedings of the Royal Society B 281 (July 22, 2014): DOI: 10.1098/rspb.2013.3254.