Canuck, I think you might under-estimate the influence of "primitive" cultures. Let's say the Maori have been in NZ for one thousand years, probably an over-estimation. Europeans have been here two hundred years. I can't put my finger on the figures but the rate of bird extinctions for the first 800 years of human habitaion is exactly the same as the last 200 years, something like forty species compared to ten species. But we shouldn't get too carried away just with humans. The ecology changes with the arrival of any new species. As I've said elsewhere it is ecology change that causes extinctions.
I prefer to stay out of the climate debate except to point out climate is constantly changing. And why should it not? There's absolutely no reason why it should be constant. Of course the real debate is whether human activity alters it. I'd presume it does, just as the activity of all forms of life on the planet do.
