The late Pleistocene extinction of large animals, began around 80 000 years ago. The cause of the debate is divided between evidence for it being human induced and/or climatically controlled. The arguement is further compounded by the timing being different on the various continents. On Australia the main extinction phase appears to be around 60 000 to 40 000 years ago. This coincides with the arrival of humans, but also with shifts in rainfall that may have impacted on ecosystems.
Events some 40,000 to 60,000 years ago marked a critical juncture in the Australian continent’s history. This is when humans first arrived and also the time when many huge beasts, known as megafauna, seem to have disappeared. So what caused their demise: humans, a changing climate, or both? The debate has been both long and polarised. Some blame changes in the prehistoric climate; others point to overhunting by the first Australians, or habitat burning by humans which drastically altered the landscape. The “human-mediated” explanations depend to an extent on the climate having remained stable over the period in question. But we have found evidence that gigantic lakes in central Australia were drying out at the time – a crucial new climate factor that probably hastened the megafauna’s demise.
https://theconversation.com/drying-inland-seas-probably-helped-kill-australias-megafauna-37527