“Why did warming climates doom the megafauna? It’s not clear, but Cooper has some guesses. The rising temperatures brought summer droughts, variable rainfall, and other weather anomalies. They also fueled the rapid growth of forests, which broke up the open habitats that these large animals were used to.
And within that changing landscape, there were people, armed with bows and spears. They may have grown faster, or roamed over greater distances. Their populations could have boomed. They might have found it easier to kill the megafauna, which had been herded into ever narrower ranges. And in a newly fragmented world, there was no way for distant populations of hunted beasts to replace those that had been hunted out.”
“This fits with a growing sense from other parts of the world that neither climate change nor humans was solely responsible for killing the megafauna. Instead, they acted synergistically. “Warming might be the magic ingredient that activates or accelerates our natural destructive tendencies,” says Cooper. “Or cold shuts us down.” Either way, climate change cocked the gun, and people pulled the trigger.”
““The evidence from the fossil record demonstrates the rapidity with which extinctions can occur and ecosystems can collapse when species are squeezed by multiple stressors that limit their ability to track habitat changes,” says Elizabeth Jeffers from Oxford University. And “these processes—rapid climate warming and habitat fragmentation by humans—are occurring today,””
“But maybe the death of today’s giants is partly driven by the same warming-related strife that doomed their prehistoric counterparts. “It becomes really pressing to work out what aspects of warming allow humans to be that much more destructive than normal,” Cooper says.”