Paul Ehrlich (Bing Professor of Population Studies, President of the Center for Conservation Biology, Department of Biology, Stanford University, and author with his wife Anne Ehrlich [uncredited] of “The Population Bomb” in 1968) (asked “It's predicted that by 2100 the world population will plateau at 11 billion. Do you still maintain that the world population will be a major problem?”): “I don't maintain it will be. It’s already is a major problem. For example, even though there are some people who would claim that - professional deniers of climate change and the danger in climate change and their pimps in the fossil fuel industry, if you think about it for a minute, every person you add to the planet releases more CO2. When they release more CO2, it is a bigger threat not just to sea level rise. Everybody thinks sea level rise is the big thing about climate change. Actually, no. Our agricultural system is utterly dependent on the distribution, quality, timing of rainfall. All that's changing. We’re already seeing changes in the productivity of the basic grains we depend on. So each person you add needs more food, contributes more greenhouse gases, which increases the assault on agriculture, which has to be spread, the agricultural system already supplies something on the order of 30% of the greenhouse gases. So there’s just one little example where things are synergising and we are setting our kids up for even worse problems”.
Dr Paul Ehrlich) (asked “You have actually maintained, I think, there is a 90% chance that our civilisation will collapse within 50 years. How do you get to that?”): “Well, that is a gut feeling and the reason it’s a gut feeling is you can't deal with the discontinuities. In other words, you can see the general trends but many people, me included, but people who look at it more closely than I do, think the chances of a nuclear war between US and the Russians is bigger now than it was during most of the Cold War. They think there is an even bigger chance of a nuclear war between India and Pakistan and there that war itself, using maybe 215 kilotonne bombs, would destroy Australia and the US as a civilisation. Who can guess what the odds are on those. You get scared. But on the general trend, I think we will be very, very fortunate to avoid a collapse and Anne and I estimated 10%. Jim Brown, who is an energy expert and the world's greatest biogeographer said, "You’re crazy. There’s only a 1% chance of avoiding a collapse when you look at things like energy return on investment and so on.” Nobody knows. Jim is willing to work to make it a 1.1% chance. Anne and I are willing to work to make it an 11% chance, but I must say, when I watch the Republican debates, I'm converging on Jim”.
Dr Paul Ehrlich (asked “Do you think we’re overpopulated?): “ Yeah, I mean there’s no question about it. Talk to your ecologists. Talk to Corey - Corey Bradshaw and I just wrote a book called Killing The Koala and Poisoning the Prairies, which is a comparison of the US and Australia’s very successful war on the environment. You’re destroying your life support systems here. You’re working at it really hard. You are also working to become a Third World country, because your specialisation, of course, is to take your raw materials, like your coal, which are going to destroy the world of your grandchildren and great grandchildren, and ship as much of it unprocessed as you possibly can out to the rest of the world. A pile of coal that Australia shifts annually would be about the size of that thing there [lecture hall] extending that way all the way around the world and back to here, that's how much coal you dig out of the ground even though every scientist in the world knows we should stop burning it as fast as we possibly can. If you want a sustainable society, you can look to Australia. The Aborigines have the longest term sustainable society on the planet, until we came along, of course, and kind of screwed it up. But they went through 40, 50,000 years of great changes and so on, managed to survive, kept their numbers reasonable. By the way, you’re quite correct. If you want to solve the population problem, give women equal rights everywhere in the world. Give them equal opportunities. Give them access to modern contraception. Give them access to safe backup abortion and the odds are that you will start to slow population...” (Paul Ehrlich interviewed on Australian TV Q&A, “GST, Gonski, Population and Diversity”, 2 November 2015: http://www.abc.net.au/tv/qanda/txt/s4321172.htm ).
Paul R. Ehrlich (Professor of population studies in the Department of Biological Sciences at Stanford University. His wife Anne H. Ehrlich is the associate director and policy coordinator of the Center for Conservation Biology at Stanford University) (2013): “But our guess is that the most serious threat to global sustainability in the next few decades will be one on which there is widespread agreement: the growing difficulty of avoiding large-scale famines. As the 2013 World Economic Forum Report put it: “Global food and nutrition security is a major global concern as the world prepares to feed a growing population on a dwindling resource base, in an era of increased volatility and uncertainty.” Indeed, the report notes that more than “870 million people are now hungry, and more are at risk from climate events and price spikes.” Thus, measures to “improve food security have never been more urgently needed.”In fact, virtually all such warnings, in our view, underestimate the food problem. For example, micronutrient deficiencies may afflict as many as 2 billion additional people. And many other sources of vulnerability are underrated: the potential impact of climate disruption on farming and fisheries; how a shift away from fossil-fuel consumption will impair food production; how agriculture itself, a major emitter of greenhouse gases, accelerates climate change; and the consequences of groundwater overpumping and the progressive deterioration of soils. Indeed, agriculture is also a leading cause of biodiversity loss – and thus loss of ecosystem services supplied to farming and other human enterprises – as well as a principal source of global toxification… Can humanity avoid a starvation-driven collapse? Yes, we can – though we currently put the odds at just 10 percent. As dismal as that sounds, we believe that, for the benefit of future generations, it is worth struggling to make it 11 percent. One of our most distinguished colleagues, biogeographer and energy expert James Brown of the University of New Mexico, disagrees. He puts the odds of sustaining human civilization at 1 percent, but thinks that it’s worth trying to increase it to 1.1 percent. Developing foresight intelligence and mobilizing civil society for sustainability are central goals of the Millennium Alliance for Humanity and the Biosphere, based at Stanford University. Those who join the MAHB join the best of global civil society in the fight to avoid the end of civilization.
” Paul R. Ehrlich “Famine threatens the very survival of human civilization” , The Daily Star, Lebanon, 16 March 2013: http://mahb.stanford.edu/wp-content/uploads/2013/03/Famine-Threatens-the-Very-Survival-of-Human-Civilization.pdf ).
Paul Ehrlich (Bing Professor of Population Studies and President of Center for Conservation Biology, Stanford University. Fellow, National Academy of Sciences and Royal Society; Crafoord Prize Laureate) on an optimal 1.5 to 2 billion people (2017): “Our research group has concluded two decades ago that with foreseeable technologies an "optimum" population might be 1.5 to 2 billion people. The idea was that would be enough people to have big cities for those who like fine restaurants and opera, and few enough people to permit lots of wildlands for hunters and hermits. Overall, we thought that number might be long-term sustainable” (Paul Ehrlich quoted in Daniel Kolitz, “What is the ideal number of humans on Earth?”, Gizmodo, 28 December 2017: https://www.gizmodo.com.au/2017/12/whats-the-ideal-number-of-humans-on-earth/ .)
Paul Ehrlich (Bing professor of population studies at Stanford University in California and author of “The Population Bomb”) (2012): “How many you support depends on lifestyles. We came up with 1.5 to 2 billion because you can have big active cities and wilderness. If you want a battery chicken world where everyone has minimum space and food and everyone is kept just about alive you might be able to support in the long term about 4 or 5 billion people. But you already have 7 billion. So we have to humanely and as rapidly as possible move to population shrinkage” (Paul Ehrlich, interviewed in John Vidal , “Cut world population and redistribute resources, expert urges”, Guardian, 26 April 2012: https://www.theguardian.com/environment/2012/apr/26/world-population-resources-paul-ehrlich .)