"Life has now entered a . This is probably the most serious environmental problem, because the loss of a species is permanent, each of them playing a greater or lesser role in the living systems on which we all depend. The species extinctions that define the current crisis are, in turn, based on the massive disappearance of their component populations, mostly since the 1800s. The massive losses that we are experiencing are being caused, directly or indirectly, by the activities of Homo sapiens. They have almost all occurred since our ancestors developed agriculture, some 11,000 y ago. At that time, we numbered about 1 million people worldwide; now there are 7.7 billion of us, and our numbers are still rapidly growing. As our numbers have grown, humanity has come to pose an unprecedented threat to the vast majority of its living companions."

"We need to realize the "load" with which we humans burden the planet's ecosystems consists of more than just a population number. People living by different cultures not only reproduce at different rates; they impose very different per capita ecological impacts. Culture includes a population's technology and people's ways of organizing themselves. Each of us living in a "developed" country (i.e., industrialized far beyond anything conceivable to Malthus) has an enormously greater resource appetite and environmental impact than does each resident of a so-called "developing" country. For our grossly unsustainable manner of living, 6 billion is far too many."

"[Hu]man[s]... have imagined... [themselves] to be more unlike other mammals than [t]he[y] really... [are], so when human behavior has shown these same characteristics, various other explanations have been put forth which have obscured the significance of population pressure itself. In the twentieth century, with human numbers enlarged and resource drawdown becoming significant, [hu]man[kind] went to war. [T]he[y] rioted in the streets. [T]he[y] committed more... crimes of violence. [...] [Their] political attitudes polarized and [t]he[y] created totalitarian governments, some of which gave license to sadistic tendencies. A generation gap widened and deepened. In spite of earnest efforts by humane activists to inhibit racism and to rectify economic inequality, disparities between people remained and animosities became more virulent. Standards of decency in behavior toward others and expectations of considerate self-restraint were eroded and degraded in many places."

"People displayed either persistent ignorance of the carrying capacity concept or naive faith that carrying capacity could always be expanded, [and] that limits could always be transcended. Such an assumption seemed to underlie the stubborn refusal of capitalists and Marxists alike to acknowledge that the myth of limitlessness had, at last, become obsolete. There was also the assumption that further advances in technology would necessarily enlarge carrying capacity, not reduce it. Enlargement of carrying capacity had been the role of technology in the past; however… there has been a reversal of this role in the industrial era. Technology has enlarged human appetites for natural resources, thus diminishing the number of us that a given environment can support."