Half Earth: Could Setting Aside 50 Percent of the World for Wildlife Really Work?

Candice Gaukel Andrews September 23, 2014 21

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,



  1. Glenys Jones January 31, 2015 at 9:11 pm - Reply

    Envisaging a future that would protect and conserve the world’s wildlife and ecosystems is a necessary step towards developing integrated national and regional plans for achieving optimal futures for well-being. See related post: https://www.linkedin.com/pulse/20141120035853-119374494-optimal-futures-for-well-being?trk=prof-post.

  2. Michael Taylor October 8, 2014 at 5:05 am - Reply

    I like the idea proposed here, but I have to admit that I can’t see it as much more than a pipe dream. There are very few places in the world where governments would be willing to give over half their land and resources to nature, and even if they did they would keep the choicest, most productive areas in human hands. Protecting our dwindling species is a key concern, but one that has no quick fix.
    One problem I have with this is using the example of Namibia, you use it as an example of a place where this 50 percent plan could be implemented. The thing is Namibia is a country with one of the lowest population densities in the world with ~2.5 million people living in an area three times the size of the United Kingdom. It is easy to see how in a country such as Namibia could put aside such a high proportion of its land, but how would a densely populated, heavily developed nation such as the UK or India achieve this.
    The best I can see from this proposal is that it drives discussion, and can lead to at least some positive change.

  3. Benjamin Triscuit October 5, 2014 at 1:06 pm - Reply

    While this is an idealistic theory of utopian human-nature interaction, I think there is a lot of value in striving towards a more “protected” earth. Wildlife corridors, as mentioned in the article, are a great model for protecting species against looming climate change while minimizing the “inconvenience” for established human populations. This offered a thorough, yet concise perspective on the subject. Thanks for sharing!

  4. Garry Rogers October 2, 2014 at 6:23 pm - Reply

    Have to agree with Louise.

  5. Louise (elle) Seager October 2, 2014 at 10:07 am - Reply

    If only, but with our own population spiraling out of control? Pipe dreams….

  6. Bonnie Harper-Lore October 1, 2014 at 5:52 am - Reply

    Back in the 1900’s a debate like this was held about “wilderness areas” being set aside.
    They were for the greater good, but only after land costs plummeted, making land available
    at an affordable cost did wilderness areas become a reality. The Biodiversity Park concept might work if land values were not so high.

  7. Alphonse Roy October 1, 2014 at 5:51 am - Reply

    Yes, that concept can work provided that every agrees to give away their land.

    Otherwise, this idea is only an imaginative statement because not all human beings on this planet are willing to surrender their land for such worthy initiative.

  8. Lorraine Dumas October 1, 2014 at 5:48 am - Reply

    Sounds plausible. Think we could get any governments to agree?!

  9. Sara Judge September 30, 2014 at 9:55 am - Reply

    I guess to some extent I can see his train of thought – the idea of long landscapes creating corridors for wildlife, etc, etc. On paper, it could work and I guess it is just an expanded version of the wildlife corridors method that is used a lot already. But again – as with many of these kinds of suggestions – I keep coming back to the fact that animals don’t recognise boundaries. Just because you make corridors and protected areas doesn’t mean they will stay within them, and as Peter and Jorge both explained, ecosystems vary and resource availability within them will inevitably change over time. I really think that this idea of separating humans and wildlife is a bit of a lost cause – we’ve tried this already and it doesn’t really work a lot of the time. As Peter noted – urban areas are supporting a lot of wildlife, whether we like it or not. I think the direction for the future is going to be learning to live with wildlife, not apart from them, in a sustainable and hopefully mutually beneficial way.

  10. Wally Elton September 28, 2014 at 5:10 pm - Reply

    Of course it would work for the purpose cited. The question is whether it is remotely possible or can serve as inspiration for efforts to save the planet.

  11. Saul Greenland September 28, 2014 at 5:07 pm - Reply

    This is an interesting idea and I don’t understand why people have criticised it so much. It makes sense. In fact, if we were to be fair to the world we should get a lot less than 50%. I like this idea along with rewilding and yes I do believe it can work.

  12. Tony Hiss September 26, 2014 at 1:20 pm - Reply

    Thanks so much for calling attention to E.O. Wilson’s “1/2 Earth” efforts to stave off a mass extinctions crisis by setting aside half the planet for other species, and to the creation of a continental-scale network of connected and protected “Long Landscapes.” His vision was spelled out to me in this month’s issue of Smithsonian Magazine. Here’s a link, with an excellent preliminary map of the North American Long Landscape system:

  13. Joel Little September 25, 2014 at 10:50 am - Reply

    Great concept and would love to see it go beyond a proposal and become a discussion. Over half of my place (167 acres) is purely for nature and the effects of my presence there are widely felt by the fauna. Linking corridors would have to be of significant width to account for edge effects and thought towards buffering such areas from inappropriate activities. Fingers crossed something comes of it!

  14. Brenda Robinson September 25, 2014 at 4:55 am - Reply

    Sounds fair to me.

  15. Jorge Soberón September 24, 2014 at 6:27 pm - Reply

    Very much agree with Peter. And it is not just ecosystem dynamics. Who will pay for this land? And many biomes are already down to 2,3, or 4% of their original surface. And ranchers, farmers, villagers, indigenous communities… will just agree?
    Much, much better to try to develop sustainable and diversified forestry, wildlife-friendly farming, perennial-annual multicropping and all the productive landscapes that do maintain a larguish proportion of biodiversity (more than heavily sprayed monocrops). Not as good as asking a few billion people to abandon their lands and move to cities, but more realistic.

  16. Mary Cheetham September 24, 2014 at 3:48 pm - Reply

    I like that this view encourages the use of large pieces of land for habitat preservation since, according to my general ecology book, large areas encourage the greatest biodiversity. Engineers would be vital- perhaps creating land bridges like those in the Netherlands to allow animals continual access to the preserved land while maneuvering around established human infrastructure. However, it seems that the main problem will always be that corporate societies like that of America are not interested in anything that would give them an economic disadvantage. Thanks for sharing the article, I had not heard this theory before.

  17. Andrew Whitman September 24, 2014 at 3:47 pm - Reply

    If you been set aside in preserves, I doubt it will work. We will need much more integrated strategies than simply land sparing in order to maintain biodiversity and the ecosystem services which humans depend upon.

  18. Peter Bridgewater September 24, 2014 at 8:45 am - Reply

    this suggestion is another nonsense. there will certainly be species losses, but there will also be changes all over the world. ecosystems are dynamic systems and to suggest that “set aside half the planet in permanently protected areas for the ten million other species with whom we share the world.” will solve anything suggest a complete lack of understanding of ecosystem dynamics.we need very different solutions to resolve these issues – and to recognize that urban areas also are places where biodiversity can flourish…

  19. Sinnadurai Sripadmanaban September 24, 2014 at 5:35 am - Reply

    Reservation for wildlife,forests,jungles,ponds,marshy lands,wetlands,parks,greenbelts,farmlands etc are vital for our survival for oxygen,fodder for animals,trees for birds,fields for crops,inland fisheries,water for animals etc. Even in some milk bottles they put milk from grazing cows instead of artificial food fed cows. Even in some poultry farms they put field grown hen’s eggs which shows that man has realised the importance of natural habitat. Even in cities people in condos (like in cages)are unnatural compared to those in rural areas.

  20. bungener September 23, 2014 at 12:14 pm - Reply

    Perhaps could we just start to think how we could integrate our activities inside ecosystem functioning?
    We need to be creative, take the time to understand the truly sense of Evolution and stop immediately to give to timing and efficiency the unrealistic value they have today. Half of the planet couldn’t be secured if we still produce toxics and waste as we do.
    It’s time to invert our relation with engines and began to use them to really save time not money.

  21. Robert N. Mowbray September 23, 2014 at 11:01 am - Reply

    Experts have been warning of a mass extinction for well over 4 years – at least since the early 1990s and probably earlier. I believe there was a National Geographic article on the subject in 1990 or earlier.

    Bob Mowbray
    Forest Ecologist

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