The planet is not what it once was for plants and animals. For millions of years, Earth belonged entirely to them (and fungi and bacteria, of course). Then humans evolved out of the pack, forever separating us and them. Now our dominance, which continues to expand through population growth and natural resource demand, has made it so only around 15% of the planet is set aside specifically for nature in reserves, parks, and other protected areas.

But what if we raised that percentage to something more fair and balanced? A more justifiable number and equal number. What if we set aside half the Earth’s surface for nonhuman life?

This is not simply a flippant rhetorical question, but the subject of a new book by esteemed naturalist, author, and Professor Emeritus at Harvard, E.O. Wilson. In “Half-Earth: Our Planet's Fight for Life,” Wilson, an entomologist by trade with an expertise in ants, makes his boldest statement yet about how humans and other creatures can coexist successfully. At the same time it is an extremely simple concept to grasp: half the planet, not for us.

If something drastic of this proportion isn’t done soon, Wilson asserts, more than half the species on the planet could be lost within a few generations. Not only is this existentially traumatic, but it would have wide-ranging negative implications for humankind. By allowing wildlife to thrive, Wilson hopes we can avoid the worst of the triage and come out better off for our efforts. According to Wilson's calculations, setting aside half the planet should allow us to preserve about 84% of all species.

A view of Denali, formerly known as Mt. McKinley, on September 1, 2015 in Denali National Park, Alaska.
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Civilization is Turning "Pale Green"

Wilson thinks these paradigm-shifting changes in how we use and value the biosphere will come about in large parts thanks to technological gains. He argues that we should be able to improve our quality of life without demanding so much from the natural world in the years to come—he calls this the “evolution of the free market system” toward energy-efficient, eco-friendly technologies.

As Jedediah Purdy recently noted in The New Republic, there isn’t much strong evidence “that human freedom and progress are compatible with long-term planetary health"—the trajectory Wilson is relying on.


Nevertheless, in a recent op-ed in The New York Times, Wilson, a self-avowed optimist, described the significance of his proposition:

Unless we wish to pauperize the natural world drastically and permanently, believing that later generations will be smart enough to find a way to bring equilibrium to the land, seas and air, then we, the current inheritors of this beautiful world, must take more serious action to preserve the rest of life.


While Wilson sees civilization as “at last turning green,” it is only “pale green."

He writes that as our focus on the physical environment—such as actual land masses and ocean regions—has strengthened in recent decades, the living environment, which includes all the species and ecosystems they compose, still gets short shrift.

“This is a huge strategic mistake,” he writes. “If we save the living environment of Earth, we will also save the physical, nonliving environment, because each depends on the other. But if we work to save only the physical environment, as we seem bent on doing, we will lose them both.”


What are Ecosystem Services in Service of?

Wilson writes that Peter Kareiva, formerly The Nature Conservancy’s senior science advisor and now the president and the director of the Institute of the Environment and Sustainability at UCLA, “has been the leader of those who attack the existence of wilderness.”

“In his opinion, there are no pristine areas left on Earth,” writes Wilson. “The regions they long ago occupied should therefore be opened to people for more sensible management and profit."


Kareiva told me he was “really puzzled” by the notion that he or anyone else Wilson associates with so-called “new conservation” ever attacked wilderness or suggested opening wilderness to people for profiteering. He said he was unable to track down the source of these comments, and that in any case he certainly does not subscribe to such a view.

“What I have said is that humanity’s impact has reached so far that even our wildest places have been touched—either with pollutants that are transported globally, or through the spread of non-native species, or through forest clearing or exploitation, and of course now by climate change,” he said. “In a sense this means that to maintain the wild things we love, we will likely have to intervene and manage these systems as opposed to just leaving them alone.”


Kareiva thinks Wilson and others may have read into this observation “a kind of happiness about the fact of Homo sapiens impact on nature.”

“It is not happiness, it is just an observation to be contended with going forward,” he said.

As for the idea of profiteering off nature, Kareiva thinks this is based on a misinterpretation of what he and many colleagues have “championed” as ecosystem services.


As an example of ecosystem services, Kareiva noted a recent project between The Nature Conservancy and The Natural Capital Project that has established over a dozen water funds in which cities invest in upstream conservation in order to secure clean water. He said “green markets” overall are thriving, such as the green building industry, and that these trends suggest that “consumers and investors and businesses can be part of the changes we need to save nature.”

“It is not that we want to see fortunes made off nature, it is that we want to see nature valued, and economic valuation is one form of value that can help drive policies that will help Professor Wilson achieve his vision,” he said.

Kareiva doesn’t entirely blame Wilson for what he sees as an unfair diagnosis of the notion of ecosystem services. He said that he is yet to find the right words, narratives, and language to “avoid misinterpretations such as Wilson’s.”


A boy plays near a fire ant sculpture at the seventh annual Fire Ant Festival March 23, 2002 in Ashburn, GA.
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The Extinction of Experience

Kareiva also has some fundamental issues with the idea of setting aside half the planet for nature, worrying that it might lead to a human-nature disconnect in which people who aren’t “frequent fliers” might not get to experience the joys of being in nature because they will be so isolated from it. He thinks that while some places must be set aside from human development, “we also need nature to thrive in our midst.”


This notion of losing that intimate connection with nature—what Kareiva referred to as “the extinction of experience”—is one that worries him and Wilson, who have both expressed how they grew up catching insects and generally playing outdoors almost every day.

Kareiva referenced a recent study from Japan that found that half the kids had never climbed a tree and around 40% had never caught an insect—a huge decline over the last 20 years. Kareiva said that while his generation grew up going outdoors to play every day, today only about one-third of American children engage in outdoor activities on a daily basis. With more than half of the world’s population already living in urban areas, a proportion that is expected to increase to two-thirds by 2050, the typical disconnect between children and nature will likely continue to grow.

Correction: This article has been updated to correct misrepresentative quotations regarding Dr. E.O. Wilson and Dr. Eileen Crist.