What caused the extinction of megafauna on the Australian continent? In his book Sapiens, Yuval Noah Harari writes that the three main factors that people consider to be the primary contributors to the extinction of megafauna on the Australian continent were human hunting, human fire agriculture, and climate change which compounded the threats from humans. Homo Sapiens arrived on the continent and upended the ecological balance that evolution had produced. Through cooperative hunting and using fire to change the environment humans threatened many larger species that reproduced slowly and couldn’t keep up with the changes that humans brought.
Harari writes, “by the time Sapiens reached Australia, they had already mastered fire agriculture. Faced with an alien and threatening environment, it seems that they deliberately burned vast areas of impassable thickets and dense forests to create open grasslands, which attracted more easily hunted game, and were better suited to heir needs. They thereby completely changed the ecology of large parts of Australia within a few short millennia.” Humans have been terrestrial menaces, working together to conquer the land in a way that no other species has ever been able to. The megafauna of Australia had evolved slowly over millennia alongside the rest of the species on the continent, but humans upended that evolution. Their group hunting overpowered the large animals that could defend themselves against a single predator. Their ability to use fire to reshaped the landscapes, took away natural habitats, and left many species vulnerable.
On top of all the change from humans was natural climate cycles. When humans destabilized the environment, existing climate changes were more severe and threatening to the existing species. “It is hard to find a good survival strategy that will work simultaneously against multiple threats,” Harari writes of the mass extinction brought to the continent by humans.
Today we are pretty sensitive to the impact we have on our planet. We don’t want to continue the mass extinctions we have been driving. We don’t want to destroy more natural habitat than is necessary. And we are concerned with our impact on global climate change. What Harari shows is that humans have been impacting the climate and causing extinctions for tens of thousands of years. This doesn’t dismiss our current concerns or excuse what we have been doing to the planet since the industrial revolution, but it does show that how we live with the rest of life on Earth is a choice, and it is an ever shifting relationship. I don’t know what it would mean to return to a natural state of humans relative to nature, I don’t know what it means to say that we need to better manage forests to prevent catastrophic wildfires, and I don’t know how we will strike the right balance with the ecosystems where we live, but we should accept that we shape the world in profound ways, and have dominated the planet often at the expense of other life.