CNN interviewed the author of a debunked population doomsday book from 1968 during a segment on climate change Monday morning.

"For a species that named itself homo sapiens, the wise man, we're being incredibly stupid," Paul Ehrlich, a professor at Stanford University, told CNN.

In his book The Population Bomb, Ehrlich projected overpopulation would have dire implications and result in widespread famine, and pushed limiting population growth.

"The human population has doubled in just 50 years, our agriculture consumes more and more land, natural habitats are shrinking, we continue to pollute, the climate continues to warm, and natural ecosystems crumble at an accelerating rate. 145 leading experts from 50 countries spent three years compiling this gargantuan report, reaching frightening conclusions," reporter Nick Watt said.

"The other organisms of the planet are our life support systems. You don't have to worry about them if you don't care about eating, if you don't care about breathing, if you don't care about having fresh water and so on. Then you can just forget about it and die," Ehrlich added.

Watt noted that "experts" such as Ehrlich call for people having fewer children.

"As for our rapidly dwindling biodiversity, these experts claim it's the 11th hour. We must act now, consuming less, polluting less, having fewer children," Watt said.

"I'm very, very optimistic about what we could do in theory. I'm very pessimistic about what we will do," Ehrlich continued.

Modern doomsday theorizing about the impact of overpopulation goes back to English political economist Thomas Robert Malthus's 1798 treatise An Essay on the Principle of Population. A Scientific American article mentions the negative consequences of Malthus's theories, which "influenced policy makers to embrace social Darwinism and eugenics, resulting in draconian measures to restrict particular populations' family size, including forced sterilizations."

Ehrlich also once said if he were a gambler, he "would take even money that England will not exist in the year 2000."

A Wall Street Journal op-ed from last April highlights Ehrlich's failed wager University of Illinois professor Julian Lincoln Simon:

Ultimately their clashing views led to a famous wager in 1980. If Mr. Ehrlich was right, prices for commodities would grow more expensive as they became scarcer. If Simon was right, they would become cheaper as humans found more cost-effective ways of extracting them or cheaper alternatives. Mr. Ehrlich picked the commodities—nickel, copper, chromium, tin and tungsten—but in 1990 lost the bet. The larger victory, however, was not about the price of tin. It was the idea that the finite supply of any given natural resource is only one part of the equation. The other is human ingenuity, which adapts to circumstances and turns what were once luxuries into everyday amenities. That’s why Julian called the human mind "The Ultimate Resource." And that’s why it never runs out.

"Fifty years out, alas, Mr. Ehrlich remains as impervious to the evidence as ever," the op-ed continues.