Some of the earlier posts had a good point about environmental destruction. Also, technology isn't the only thing that tends to cause it - settled agriculture often causes it. Once people live in one area and develop staple foods the population grows and the local resources become heavily exploited - often resulting in mass deforestation and sometimes climate change (as is thought to have occured in some areas of the middle east). In fact many hunter-gatherer societies have been wiped out by settled agriculture through being outbred. For example, in Japan the native Japanese are actually quite hairy. Originally they were a hunter gatherer society but the koreans came over and developed settled agriculture. It is thought that they actually lived side by side for a long time but the high reproductive rate of the farmers meant that most of the native Japanese were out bred (some still remain in the North).
P.S. I'm an ecologist rather than an anthroplogist, but I did read this in Scientific American.