From the 1996 book, Betrayal of Science and Reason, by Paul R. Ehrlich and Ann H. Ehrlich:
“The choice is between permitting the continued depletion of America’s vital natural capital and making an all-out effort to save it. Science tells us that America’s population cannot keep expanding perpetually, always demanding more and more from the nation’s finite living and non-living resources. The Endangered Species Act at the very least acknowledges the preservation of living resources as a high priority, which was a historical first. By attempting to shield those resources from the piecemeal destruction that is ensured when each species is measured against some perceived immediate economic gain, it helps set the United States on a path toward sustainability.”
“Our massive tampering with the world’s interdependant web of life—coupled with the environmental damage inflicted by deforestation, species loss, and climate change–could trigger widespread adverse effects, including unpredictable collapses of critical biological systems whose interactions and dynamics we only imperfectly understand.
“Uncertainty over the extents of these effects cannot excuse complacency or delay in facing threats.
“The earth is finite. It’s ability to absorb waste and destructive affluent is finite. It’s ability to provide food and energy is finite. It’s ability to provide for growing numbers of people is finite. And we are fast approaching many of the earth’s limits. Current economic practices that damage the environment, in both developed and underdeveloped nations, cannot be continued without the risk that vital global systems will be damaged beyond repair.
“Pressures resulting from unrestrained population put demands on the natural world that can overwhelm any efforts to achieve a sustainable future. If we are to halt the destruction of our environment, we must accept limits to that growth. A World Bank estimate indicates that world population will not stabalize at less than 12.4 billion, while the United Nations concludes that the eventual total could reach 14 billion, a near tripling of today’s 5.4 billion. But, even at this moment, one person in five lives in absolute poverty without enough to eat, and one in ten suffers serious malnutrition.
“No more than one or a few decades remain before the chance to avert the threats we now confront will be lost and the prospects for humanitty immeasurably diminish.
“We the undersigned, senior members of the world’s scientific community, hereby warn all humaity of what lies ahead. A great change in our stewardship of the earth and the life on it is required if vast human misery is to be avoided and our global home on this planet is not to be irretrievably mutilated.”
Under the five things we must do, Ehrlich cites, “We must bring environmentally damaging activities under control to restore and protect the integrity of the earth’s systems we depend on. We must, for example, move away from fossil fuels to more benign, inexhaustable energy sources to cut greenhouse gas emissions and the pollution of our air and water. … We must halt deforestation, injury to and loss of agricultural land, and the loss of terrestrial and marine plant and animal species.” …
And again, “We must stablize our population.”