Final answer:
The extinction of numerous Australian species, including large megafauna, has been attributed to the arrival of modern humans around 40,000 to 50,000 years ago. The pattern of extinctions aligns with human colonization and overhunting, rather than climate change.
Step-by-step explanation:
The extinction of Australia's large fauna in the last 40 thousand years has been tied to the arrival of modern humans. The evidence suggests that the Pleistocene extinctions began about 40,000 to 50,000 years ago, closely following the arrival of humans. Species such as the marsupial lion, a giant wombat, and several species of giant kangaroos are among the notable losses. This pattern of extinction coincides with human arrivals in various regions and is not strictly correlated with climate-change events, with the exception of Eurasia and Africa where humans had arrived much earlier. While climate may have played a role, in most cases it is likely that overhunting by humans precipitated the extinctions.