If E. O. Wilson’s Half Earth plan becomes a reality, you’ll almost always be in a “national biodiversity park” or in a landscape that leads to one. ©Patrick J. Endres

Although experts have been warning of an imminent sixth mass extinction for almost four years, to date most conservation appeals for battling the crisis have been, at best, attempts to stem the tide. None have claimed to be permanent and sustainable solutions—until now.

Renowned evolutionary biologist and author E. O. Wilson believes that the only way we can avoid an extinction event as devastating as the one that killed the dinosaurs 65 million years ago is to set aside half the planet in permanently protected areas for the 10 million other species with whom we share the world. The concept, known as “Half Earth,” simply means half of the globe for us and half for them.

It might sound like a pie-in-the-sky ideal, but could it actually work?

In Namibia, conservancies cover 20 percent of the land area. ©Matt & Maggie Kareus

Long on landscapes

In May of this year, a study published in the journal Science revealed that humans are causing wild species to disappear at 1,000 times the natural rate, mostly due to human-caused climate change, deforestation, habitat encroachment, overfishing, pesticides, poaching and pollution. Even in protected areas, animals, plants and invertebrates are rapidly vanishing. Dr. Wilson, in conjunction with ecologist and mathematician Robert MacArthur, formulated the theory of “island biogeography” to explain how confined landscapes—such as national parks—inevitably lose species over time as environments change and animals and plants find they have nowhere else to go.

Permanently protecting half the planet is the only viable solution, according to Dr. Wilson. However, it’s not quite as simple as just drawing a line in the sand and dividing the world into a protected area and a unprotected one. Wilson believes that a series of “long landscapes”—chains of uninterrupted corridors with twists and turns that link up national parks, wilderness reserves and restored landscapes—stretching north to south and east to west will allow species to migrate seasonally and to relocate as climate change alters their environments.

There are already some such corridors in place and plans for more of them. In the American West, the Yellowstone-to-Yukon corridor, a north-south conservation initiative that will join 2,000 miles of public and private lands running from Wyoming to the Yukon Territory in Canada, will let life move north as the climate warms. Corridors that run east-west, such as the Western Wildway, a 5,000-mile-long arc of land along the length of the Rockies from Mexico to Alaska, will allow species to travel east, away from the increasingly dry Western landscapes.


The Yellowstone-to-Yukon corridor that runs from Wyoming to Canada’s wild Yukon Territory will allow wildlife to travel farther north as the climate warms.

Creating such corridors involves not only public lands but private holdings, as well. The 9.1 million acres of American wilderness protected in 1964 with the signing of the Wilderness Act have since grown to 109.5 million acres (about 5 percent of the country). To augment that acreage, Wilson says that “conservation easements” need to be incorporated, where individual landowners are approached one at a time and paid to keep their properties wild so that animals and plants have seamless connections between previously protected parcels.

Dr. Wilson envisions a country where we’ll be so surrounded by connected corridors that we’ll almost always be in “national biodiversity park” or a landscape that leads to one.

Short on sense

Those who think E. O. Wilson’s Half Earth theory is merely pie-in-the-sky dreaming say that the concept, at best, will be a very tough sell. It would mean limiting the spread of the human population and sacrificing access to natural resources—not something that the vast majority of people will accept or vote for. And although easements cost far less than outright land purchases, finding the money to fund the Half Earth proposal will be problematic.

Costa Rica is already halfway to Half Earth. ©Patrick J. Endres

Some critics, such as David Ropeik, an instructor at Harvard, go further and state that it’s anthropocentric arrogance to think that humans are more than only a temporary part of a natural system that is vastly more rich and complex than we appreciate. He believes that while we are surely mucking things up, nature is phenomenally more powerful and resilient than we give it credit for and that it will be alive and thriving long after we’re gone. Putting in place measures such as Wilson’s Half Earth is naïve and pompous.

I’m not so sure that the Half Earth proposal couldn’t work. Take a look at Namibia. In that nation, 79 wildlife conservancies cover about 20 percent of the country, and 41 percent of Namibia’s land is communal. And, according to the World Bank, as of 2012, Costa Rica has placed 26.9 percent of its terrestrial area in protection.

That country is already halfway to Half Earth.

Do you think the Half Earth theory could work if put into practice? Is it the best hope for avoiding a sixth mass extinction?

Here’s to finding your true places and natural habitats,