Because we are the cause of our environmental problems, we are the ones in control of them, and we can choose or not choose to stop causing them and … - Jared Diamond

In fact, one of the main lesson to be learned from the collapses of the Maya, Anasazi, Easter Islanders, and those other past societies (as well as from the recent collapse of the Soviet Union) is that a society's steep decline may begin only a decade or two after the society reaches its peak numbers, wealth, and power. [...] The reason is simple: maximum population, wealth, resource consumption, and waste production mean maximum environmental impact, approaching the limit where impact outstrips resources. On reflection, it's no surprise that declines of societies tend to follow swiftly on their peaks.

We have already discovered two species that are very intelligent but technically less advanced than us — the common chimpanzee and pygmy chimpanzee. Has our response been to sit down and try to communicate with them? Of course not. Instead we shoot them, stuff them, dissect them, cut off their hands for trophies, put them on exhibit in cages, inject them with AIDS virus as a medical experiment, and destroy or take over their habitat. That response was predictable, because human explorers who discovered technically less advanced humans also regularly responded by shooting them, decimating their populations with new diseases, and destroying or taking over their habitat. Any advanced extraterrestrials who discovered us would surely treat us in the same way...If there really are any radio civilizations within listening distance of us, then for heaven's sake let's turn off our own transmitters and try to escape detection, or we are doomed.

As we shall see in this book's chapters, traditional societies are far more diverse in many of their cultural practices than are modern industrial societies. [...] Yet psychologists base most of their generalizations about human nature on studies of our own narrow and atypical slice of human diversity. [...] That is, as social scientists Joseph Henrich, Steven Heine, and Ara Norenzayan express it, most of our understanding of human psychology is based on subjects who may be described by the acronym WEIRD: from Western, educated, industrialized, rich, and democratic societies. [...] Hence if we wish to generalize about human nature, we need to broaden greatly our study sample from the usual WEIRD subjects [...] to the whole range of traditional societies.