Three academic scientists--Anne H. Ehrlich and Paul R. Ehrlich of Stanford University and Gerardo Ceballos of National Autonomous University of Mexico--come together in a plea to halt Earth's sixth mass extinction. The attractive, large-format The Annihilation of Nature: Human Extinction of Birds and Mammals contains original illustrations by Ding Li Yong and 83 color photographs to accompany the authors' heartfelt arguments about the value of global and regional biodiversity and the danger of extinction that currently faces so many species.

As stated in the preface, the goals of this project are to share the dire conditions with the general public, and convince that audience of the relationship between the continuing health of these diverse species and human well-being. In pursuit of these objectives, the authors have chosen to highlight mammals and birds specifically, because they are visible, sympathetic and thus likely to appeal to human compassion. The Annihilation of Nature is plainly written, well-organized and filled with arresting images.

Ceballos, Ehrlich and Ehrlich begin by describing the incredible richness of Earth's diverse forms of life, which they call a "legacy"--humanity's duty to protect and appreciate. They outline the planet's previous five waves of mass extinction and their natural causes, making the point that the present sixth event is different in that it is caused by human actions. The current time period is called by many scientists "the Anthropocene," in which "a huge and growing human population has become the principal force shaping the biosphere (the surface shell of the planet's land, oceans, and atmosphere, and the life they support)." To illustrate the interrelatedness of human actions with every natural system, basic concepts such as the food chain are reviewed. The bulk of the book is then devoted to four chapters on extinct birds, endangered birds, extinct mammals and endangered ones. A combination of illustrations and photographs brings the reader's attention to the long-gone dodo and the passenger pigeon, and species in need of conservation like the Philippine monkey-eating eagle and the New Zealand kakapo (a nocturnal flightless bird). Extinct mammals include the baiji--a freshwater dolphin endemic to China, called the "goddess of the Yangtze"--and the Tasmanian tiger, a marsupial predator with several unique physical features including striped patterning and rearward-facing pouches on individuals of both sexes. Mammals in danger today include a variety of large species: whales, big cats (lion, tiger, cheetah), bears, apes, rhinoceros and elephants, joined by the small but scrappy Tasmanian devil.

All life forms in an ecosystem are intricately interconnected. When gray wolves were reintroduced to Yellowstone National Park, their impact was profound and widespread: elk populations came under control and trees such as aspen, willow and cottonwood began to recover. The health of the willow helped beavers to rebound and beavers in turn improved riparian conditions and contributed to healthy populations of fish, waterfowl, amphibians and reptiles, as well as regulating stream flow. Songbirds have returned to the park in greater numbers with its new tree growth. Smaller predators have declined in numbers, which in turn increases numbers of small prey and then of mid-level predators like foxes and bald eagles. All these benefits came from the reintroduction of one keystone predator.

Having shared the remarkable and evocative profiles of so many creatures, the authors make their central point in chapter 8, "Why It All Matters." Here they lay out the many human-caused factors that contribute to species extinction and population extinction, including habitat destruction; chemical pollution and plastic debris; the introduction of non-native species and diseases; legal hunting and illegal poaching for meat or valued body parts such as tusks, horns and organs; and killing because of competition for food sources (the Sumatran orangutan, which vies with farmers for fruit) or because some species are seen as pests (crop-raiding Asian elephants) or predators of livestock (the gray wolf). Finally, climate change is deemed a major cause of ecological upheaval and extinction. If forced to choose a number-one factor, the authors name toxic pollutants, but climate change "may be the most threatening problem ever faced by humanity" and "climate change alone could be sufficient to finish the sixth great extinction now under way."

Finally, Ceballos, Ehrlich and Ehrlich argue that biodiversity must be valued and protected for many reasons, from the aesthetic and ethical through the services they provide to the world's ecosystems and to humans: dispersal of seeds, insect and pest control, pollination and the sanitation role of scavengers such as vultures. Keystone species are described as those with an outsized impact on their environment. In an impassioned final chapter, the authors touch on means to conserve threatened species, including the question of direct or personal action versus institutional change. They consider ethical questions, such as whether to allow limited sport hunting of African elephants to help fund their conservation, and end with a message of hope, despite the dire picture painted by most of the book. "If we could just adopt a global policy of humanely and fairly limiting the scale of the human enterprise, gradually reducing the population size of Homo sapiens, curtailing overconsumption by the rich (while increasing needed consumption by the poor), then we might leave some room for the natural systems all humanity depends on."

The Annihilation of Nature shows a deft hand with the complexities of its subject, as when wind turbines--good for the reduction of fossil fuel use--turn out to threaten insectivorous bats and the endangered California condor, or in discussing the economic inefficiency of allowing a species to die off to the brink of extinction (or even paying subsidies to kill them, as with the black-tailed prairie dog) and then spending millions to conserve the same species. This is a beautifully produced, deeply moving, powerful story that communicates what it intended to, with great emotional impact. --Julia Jenkins

Paul Ehrlich

Anne Ehrlich

Gerardo Ceballos

Paul R. Ehrlich is the Bing Professor of Population Studies and the president of the Center for Conservation Biology at Stanford University. Among his more than 40 books are The Population Bomb and Human Natures: Genes, Cultures, and the Human Prospect. He is one of three authors of The Annihilation of Nature, along with Gerardo Ceballos, one of the world's leading ecologists and a professor at the Institute of Ecology at National Autonomous University of Mexico (UNAM), and Anne H. Ehrlich, a senior research scientist emeritus at Stanford University. Anne Ehrlich is the coauthor of Extinction: The Causes and Consequences of the Disappearance of Species and The Dominant Animal: Human Evolution and the Environment. Ceballos is the author of Mammals of Mexico and Diversity of Mexican Fauna.

What is meant in your subtitle by the phrase "human extinction"?

There's not the slightest question in anybody's mind of why we're facing an extinction crisis, both of populations and of species, and that's human activities. It's not extinction of humans, it's humans forcing birds and mammals to extinction.

How does the three-author cooperative process work?

First of all, Gerardo's first language is Spanish, mine is bad English and Anne's is excellent English. Usually Gerardo, or I, or Anne will sketch out a chapter, depending on where our expertise lies. I will edit it the first time around and ask Gerardo to explain some things--his English is excellent, by the way; no one has any trouble understanding him or understanding what he writes--but it's not colloquial enough in places. Then Anne goes through and replaces all my split infinitives and stuff like that. It's really an ongoing process. Gerardo is more in charge of the photographs in this particular book--he's a wonderful photographer on his own, he's published many books of photographs. We all have students and others who've helped us. None of us publishes anything in areas that are even slightly controversial without having a lot of colleagues go over it, and of course we had that done for this book, too.

The cooperative writing process is three equal parts. The effort is equal, but we all have somewhat different talents and do somewhat different things.

Who is your target audience for this book?

Our target audience is intelligent people who read books. It's not highly technical, but it's not dumbed down in any way. We hope to make it both an attractive book and one that's good reading. The whole idea is to introduce people to what we're losing. The average person on Wall Street has never seen a natural ecosystem or, say, the animals on the plains of Africa, and can't really picture what's going on. We hope to get people to picture what we're losing and get them to do something about it.

What does "climate disruption" mean, and why use that phrase rather than the more familiar "climate change"?

We adopted that phrase from the one used by Obama's science adviser John Holdren, who's a close friend of ours. He pointed out that it isn't just warming--that we are changing the entire climate. Things like the frequency of hideous storms are going to increase, and not every place may get warmer: some places may get cooler. "Disruption" is more accurate than "global warming," and even "climate change" doesn't carry the implication of speed. We know the climate has always changed, and most people, certainly the people who will read this book, would know that there were ice ages and things like that. So one of the big issues that's highlighted by using "climate disruption" is that the change is rapid. Getting older does not disrupt your life, but if you get married or divorced, that's disruptive. That's the main reason for using "disruption."

Presumably many endangered species of birds and mammals didn't fit into this book. How did you choose which species to discuss?

We chose the ones, first of all, that we know best. One of the problems, covered by a paper I was just involved in that got a lot of publicity, is trying to figure out whether or not we can prove beyond a shadow of a doubt that we're experiencing a mass extinction. One issue is that there are not enough biologists to track all the species we think may be endangered or, in fact, gone. For this book we wanted a good variety of birds and mammals--the organisms most people relate to and certainly the ones we know most about in these terms. For instance, I've spent a lot of my life working with butterflies, but there are very few butterfly populations where we know enough about what's happening to say anything statistical about the rate of extinction. But birds and mammals we know. We know which ones we know interesting stories about, and there are a wide variety of them in a wide variety of circumstances. So this isn't an attempt to analyze what's happening to all birds and mammals, but rather to take a bunch of interesting examples and tie them into why it really counts.

What about animal species beyond birds and mammals, and extending into plants--what is the scope of mass extinction relative to the story told in your book?

The scope of the mass extinction is vast, but population extinctions are the absolutely critical thing. There are a whole series of reasons not to wipe out the only other living things we know about in the universe: one, of course, is just that they're interesting, fascinating and beautiful, but many people would consider it more important that they're working parts of our life-support systems. The importance of population extinctions is easily illustrated. If we could somehow miraculously preserve one population of every species on the planet, just one, permanently, we would lose no species diversity--but we'd all be dead in a few weeks, because we utterly depend on having lots of populations to provide us with what are called ecosystem or natural services. For example, honeybees are involved in producing something like $18 billion of agricultural produce in the United States--critical to giving us a much more varied and nutritious diet. If they all died out, we'd be in deep trouble, even though they could persist in, say, Italy and Africa and we would not have lost a species, but we would have lost a vast number of populations. And population extinctions necessarily go on at a much higher rate than species extinctions, because no species goes extinct until every one of its populations has been driven to extinction.

The stories that we tell in this book make up maybe 5% of the relatively well-known stories of species extinctions. But there are many more: for instance, we didn't look at most of the so-called threatened species, the ones that the International Union of Conservation of Nature considers to be in great danger but they're not sure exactly how much. In other words, we've taken the ones where we know a lot about the endangerment, we know a lot about the distribution, and where they have really interesting stories. If you look at mouse lemurs in Madagascar, we've discovered that there are many more different ones than people thought 25 years ago. I think it went from something like two species to 12. That also means that it added substantial endangerment. If there were only two species, the chances of losing either one were relatively small. When we discover there are really 12, all of a sudden there's more endangerment. But the danger there is the same as the danger everywhere--destruction of habitat is the main thing--so it wouldn't be interesting to tell the stories of 12 mouse lemurs. We felt it was better to find the most interesting stories to tell. --Julia Jenkins

Photographs from The Annihilation of Nature: Human Extinction of Birds and Mammals by Gerardo Ceballos, Anne H. Ehrlich and Paul R. Ehrlich, Johns Hopkins University Press, 2015.
Author photos: Gerardo Ceballos courtesy Instituto de Ecología, UNAM; Anne Ehrlich by Anne Hammersky; Paul Ehrlich courtesy of the author.