The Conservation Scholars series highlights leaders in conservation science and includes a small biography, a list of major scientific publications and a Q & A on each person’s particular area of expertise.
Our thirteenth Conservation Scholar could easily be placed on the ‘Grandfather of Conservation Biology’ pedestal – Paul Ehrlich. He really needs little introduction, but I’m honoured to do so here for those few wayward souls who don’t know about him. I had the immense pleasure of having lunch with Paul last week at Stanford University and found him to be immensely entertaining and stimulating. I’ve not yet worked with the ‘Grandfather’ (although I do have a chapter ‘in press’ in a book he has co-edited with Navjot Sodhi due out later this year), but I do hope I get the opportunity soon. Introducing one of the more thought-provoking scientists today, Paul Ehrlich (WARNING: you will probably feel inadequate after reading his bio).
Paul Ehrlich is the Bing Professor of Population Studies and President of the Center for Conservation Biology, Department of Biology, Stanford University. He has been a member of the Stanford University faculty since 1959. His research focuses on population biology (including ecology, evolutionary biology, behaviour, and human ecology and cultural evolution). Ehrlich has carried out field, laboratory and theoretical research on a wide array of problems ranging from the dynamics and genetics of insect populations, studies of the ecological and evolutionary interactions of plants and herbivores, and the behavioural ecology of birds and reef fishes, to experimental studies of the effects of crowding on human beings and studies of rates of cultural evolution. He collaborates with colleagues in biology and in the disciplines of economics, psychology, political science, and the law, in policy research on the human predicament.
As a writer, Ehrlich is prolific. He has authored and coauthored some 950 scientific papers and articles in the popular press and over 35 books, including The Population Bomb, The Process of Evolution, Ecoscience, The Machinery of Nature, Extinction, Earth, The Science of Ecology, The Birder’s Handbook, New World/New Mind, The Population Explosion, Healing the Planet, Birds in Jeopardy, The Stork and the Plow, Betrayal of Science and Reason, A World of Wounds, Human Natures, Wild Solutions, On the Wings of Checkerspots, One with Nineveh and The Dominant Animal. Ehrlich is a member of many scientific societies and organisations, serving as director or board member for many; and was President of the American Institute of Biological Sciences. He is a Fellow of the American Association for the Advancement of Science and the American Academy of Arts and Sciences, and a member of the United States National Academy of Sciences and the American Philosophical Society. He is an Honorary Member of the British Ecological Society. Among his many other honours: the First AAAS/Scientific American Prize for Science in the Service of Humanity; the Royal Swedish Academy of Sciences, Crafoord Prize in Population Biology and the Conservation of Biological Diversity (an explicit replacement for the Nobel Prize for disciplines where the Nobel is not given); a MacArthur Prize Fellowship; the Volvo Environment Prize; and the International Center for Tropical Ecology, World Ecology Medal; International Ecology Institute Prize; UNEP Sasakawa Environment Prize; the Heinz Award for the Environment; the Tyler Prize for Environmental Achievement; the Heineken Prize for Environmental Sciences; the Blue Planet Prize of the Asahi Glass Foundation, Japan; the Eminent Ecologist award of the Ecological Society of America and the Ramon Margalef Prize for Ecology and Environmental Sciences. Ehrlich has appeared as a guest on many hundreds of TV and radio programs including some 20 on Johnny Carson’s Tonight Show; he also was a correspondent for NBC News. In addition, he has given hundreds of public lectures in the past 40 years.
Questions and Answers
1. There have been many estimates of our changes to ‘background’ extinction rates. How much and in what ways do you believe humanity is changing biodiversity extinction patterns?
The major ways we are accelerating rates of both population extinctions (most important because they reduce ecosystem services and presage species extinctions) include:
- Continuing land-use change, especially in aid of agriculture (including biofuels production), leading to habitat fragmentation and destruction,
- Causing ever greater climate disruption,
- Dispersing increasing quantities of toxic substances, especially those which are hormone mimics and may have non-linear dose-response curves,
- Moving organisms into areas they did not previously occupy.
The drivers of all of this are, of course, human population growth, over-consumption by the rich, and the continuing use of environmentally malign technologies.
2. Your famous 1968 scenarios in The Population Bomb have been highly contentious over the years. The events you envisaged may not have eventuated yet, but we still seem to be headed towards over-population and resource depletion. Since your last major book on this issue, The Population Explosion in 1990, how would you update your views now?
Signs of potential collapse, environmental and political, seem to be growing, many elements going in the same directions as suggested by The Population Bomb scenarios (which were explicitly stated not to be predictions): famine, disease, resource wars, etc. The pattern remains classic – population grows to the limits of current technologies to support it, followed by technological innovation (e.g., long canals in Mesopotamia, green revolution in India, biofuels in Brazil and U.S.) accompanied by more population growth and environmental deterioration, while politicians and elites fail to recognise the basic situation and focus on expanding their own wealth and power. The current failure to do anything serious about climate disruption is an instructive example.
On the population side, it is clear that avoiding collapse would be a lot easier if humanity could entrain a gradual population decline toward an optimal number. Our group’s analysis of what that optimum population size might be like came up with 1.5 to 2 billion, less than one third of what it is today. We attempted to find a number that would maximise human options – enough people to have large, exciting cities and still maintain substantial tracts of wilderness for the enjoyment of outdoors enthusiasts and hermits. Even more important would be the ability to maintain sustainable agricultural systems and the crucial life support services from natural ecosystems that humanity is so dependent upon. But too many people, especially those in positions of power, remain blissfully unaware of that dependence.
The Population Bomb certainly had its flaws, which is to be expected. Science never produces certainty. Nonetheless, we are all, scientists or not, always attempting to predict the future (will the stock go up or down? Will he be a good husband? Will it rain later?). And when we plan, we do the best we can. One of our personal strategies has always been to have our work reviewed carefully by other scientists, and The Population Bomb and Population Explosion were certainly no exceptions. Both were vetted by a series of scientists, including top leaders in the scientific enterprise. That is one reason that long ago the fundamental message of The Bomb moved from a somewhat heterodox view to a nearly consensus view of the scientific community. Consider the following two 1993 statements. The first was the World Scientists’ Warning to Humanity, released by the Union of Concerned Scientists (1993) and signed by more than 1500 of the world’s leading scientists, including more than half of all living Nobel Laureates in science. The second was the joint statement by 58 of academies participating in the Population Summit of the World’s Scientific Academies, including the U.S. National Academy of Sciences, the British Royal Society, and the Third World Academy.
The World Scientists’ Warning said in part: “Human beings and the natural world are on a collision course. Human activities inflict harsh and often irreversible damage on the environment and on critical resources. If not checked, many of our current practices put at serious risk the future that we wish for human society and the plant and animal kingdoms, and may so alter the living world that it will be unable to sustain life in the manner that we know. Fundamental changes are urgent if we are to avoid the collision our present course will bring about.”
Part of the Academies’ pronouncement read: “the magnitude of the threat… is linked to human population size and resource use per person. Resource use, waste production and environmental degradation are accelerated by population growth. They are further exacerbated by consumption habits.… With current technologies, present levels of consumption by the developed world are likely to lead to serious negative consequences for all countries…. As human numbers further increase, the potential for irreversible changes of far-reaching magnitude also increases.”
These statements recognised that humanity has reached a dangerous turning point in its domination of the planet, a view even more common in the scientific community today. The same genius that allowed us to achieve that dominance now must be harnessed if we are to prevent our very success from sealing our doom. When The Population Bomb was written I was very optimistic about what could be done to avoid collapse and pessimistic about what humanity would do. Now I’m optimistic about what could be done, but very, very pessimistic about what will be done.
3. What would be the best ways to manage human over-population?
Work much harder to give women education, job opportunities, access to safe contraception and back-up abortion, and equal rights — world wide. The most overpopulated nation — third in numbers and first among large countries in per-capita consumption — the United States should recognise its impacts on Earth’s life-support systems and develop a comprehensive population policy.
4. Raising awareness in people to value species intrinsically has failed to curtail extinctions. Economic valuing of biodiversity and ecosystem services is another approach, but we still seem to be a long way off. What else can we do to convince people not to destroy biodiversity?
This is basically a problem of public education and changing the course of cultural evolution. We know more than enough science to know what directions humanity should be moving; the problems is now in the academic ballpark of the social sciences and humanity. A group of scholars is trying to get a Millennium Assessment of Human Behavior (MAHB) going. It is still in a very preliminary stage — among other things to initiate a global discussion among peoples on what people or for and how they can deal with the human predicament.