Rapid climate-warming events are majorly responsible for the extinction of the megafauna of the last Ice Age, including the woolly mammoths, cave lion and short faced bears, says a new study.
During the unstable climate of the Late Pleistocene (about 60,000 to 12,000 years ago) abrupt climate spikes called interstadials increased temperatures between four and 16 degrees Celsius in a matter of decades.
Giant animals found it tough to survive in these hot conditions, possibly because of the effects it had on their habitats and prey.
"Interstadials are known to have caused dramatic shifts in global rainfall and vegetation patterns," said first author Alan Cooper from the University of Adelaide in Australia.
Temperature drops during the Late Pleistocene showed no association with animal extinctions, said the study published in the journal Science.
But only the hot interstadial periods were associated with the large die-offs that hit populations (local events) and entire species of animals (global events).
"By disrupting the animals' environments, human societies and hunting parties likely made it harder for megafauna to migrate to new areas and to refill areas once populated by animals that had gone extinct," said Cooper.
The extinction events were staggered over time and space since the interstadial warming events had different effects on different regions.
"In many ways, the rise of atmospheric carbon dioxide levels and resulting warming effects are expected to have a similar rate of change to the onset of past interstadials, heralding another major phase of large mammal extinctions," said Cooper.
"This study is a bit of a wake-up call," said Eline Lorenzen, an assistant professor of paleogenetics at the University of Copenhagen in Denmark.