Not sure, but it looks like it was a combination of things. Clearly mankind was around and was hunting the animals. That being said, we don't tend to hunt things to extinction.
That is not to say that man is not capable of this, simply that it becomes rather hard to cover all the ground necessary to hunt something to extinction. This is especially unlikely with those type of tribes. Take the African elephant.
They are endangered, but the major reason they are endangered is artificially created. Their ivory is extremely valuable. If their tusks were not so valuable, Africans certainly would not be hunting them to near extinction.
That being said, I am not buying the whole climate change thing. Take the American lion. It was seen all the way down to Peru.
From North America to Peru is a VERY large diversity in climate. AND a change in temp of far more than say 10 degrees. Perhaps it was a climate change that killed them off, but I doubt it was just temperature.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.