5. Paul Ehrlich, a former science adviser to president George W. Bush and the author of “The Population Bomb”: “Solving the population problem is not going to solve the problems of racism… of sexism… of religious intolerance… of war… of gross economic inequality. But if you don’t solve the population problem, you’re not going to solve any of those problems. Whatever problem you’re interested in, you’re not going to solve it unless you also solve the population problem.”

6. Dave Foreman, the co-founder of Earth First: “We humans have become a disease, the Humanpox.”

7. CNN Founder Ted Turner: “A total world population of 250-300 million people, a 95% decline from present levels, would be ideal.”

8. Japan’s Deputy Prime Minister Taro Aso about medical patients with serious illnesses: “You cannot sleep well when you think it’s all paid by the government. This won’t be solved unless you let them hurry up and die.”

9. David Rockefeller: “The negative impact of population growth on all of our planetary ecosystems is becoming appallingly evident.”

10. Richard Branson: “The truth is this: the Earth cannot provide enough food and fresh water for 10 billion people, never mind homes, never mind roads, hospitals and schools.”

11. Environmental activist Roger Martin: “On a finite planet, the optimum population providing the best quality of life for all, is clearly much smaller than the maximum, permitting bare survival. The more we are, the less for each; fewer people mean better lives.”

12. HBO personality Bill Maher: “I’m pro-choice, I’m for assisted suicide, I’m for regular suicide, I’m for whatever gets the freeway moving – that’s what I’m for. It’s too crowded, the planet is too crowded and we need to promote death.”

13. Al Gore: “One of the things we could do about it is to change the technologies, to put out less of this pollution, to stabilize the population, and one of the principal ways of doing that is to empower and educate girls and women. You have to have ubiquitous availability of fertility management so women can choose how many children to have, the spacing of the children… You have to educate girls and empower women. And that’s the most powerful leveraging factor, and when that happens, then the population begins to stabilize and societies begin to make better choices and more balanced choices.”

14. MIT professor Penny Chisholm: “The real trick is, in terms of trying to level off at someplace lower than that 9 billion, is to get the birthrates in the developing countries to drop as fast as we can. And that will determine the level at which humans will level off on earth.”

15. Julia Whitty, a columnist for Mother Jones: “The only known solution to ecological overshoot is to decelerate our population growth faster than it’s decelerating now and eventually reverse it—at the same time we slow and eventually reverse the rate at which we consume the planet’s resources. Success in these twin endeavors will crack our most pressing global issues: climate change, food scarcity, water supplies, immigration, health care, biodiversity loss, even war. On one front, we’ve already made unprecedented strides, reducing global fertility from an average 4.92 children per woman in 1950 to 2.56 today—an accomplishment of trial and sometimes brutally coercive error, but also a result of one woman at a time making her individual choices. The speed of this childbearing revolution, swimming hard against biological programming, rates as perhaps our greatest collective feat to date.”

16. Colorado State University Professor Philip Cafaro in a paper entitled “Climate Ethics and Population Policy”: “Ending human population growth is almost certainly a necessary (but not sufficient) condition for preventing catastrophic global climate change. Indeed, significantly reducing current human numbers may be necessary in order to do so.“