“Unless humanity learns a great deal more about global biodiversity and moves quickly to protect it, we will soon lose most of the species composing life on Earth.” – E.O. Wilson

Geoffrey Holland – What is biodiversity, and why must it be protected?

Paula Ehrlich – Biodiversity is all the life around us, all the variation of life found on Earth. It’s the species that make up the web of life of which we are a part. Biodiversity matters because each and every species matters.

Sam Anderson wrote about this in a New York Times article in 2021, about why the death of the last two northern white rhinos matters. He noted that rhinos are a load-bearing strand of an elaborate ecological web and are not just a part of the world, but are a world unto themselves. Rhinos move and plow fields, which feed colonies of insects; birds come to feed on the insects, and other predators come to watch the birds. It’s an ecosystem of its own. And we too, are a part of that web and sooner or later, our strand will be cut. So that’s why we must protect biodiversity. The organisms that surround us have evolved over 3.8 billion years to create an exquisite balance of interconnected resilience. It’s the foundation for all of life on this planet.

GH – Our Earth has experienced mass extinction events in the distant past. Why is the emerging sixth mass extinction event different?

PE – The difference is that human activity is its driving force. Human activities include habitat destruction, including that caused by climate change, invasive species, species that attack crops and native vegetation or cause disease, pollution, population growth, and overhunting. The good news is that we can do something about it, right away.

GH – In the 1950s, E.O. Wilson and his partner Robert McArthur developed the groundbreaking Theory of Island Biogeography. What does it tell us about the factors that drive biodiversity loss?

PE – The Theory of Island Biogeography was truly groundbreaking, and grew out of simple curiosity. E.O. Wilson was curious in the 1950s about how the size of an island would affect the number of species living there, and so he and his colleagues did some experiments to test and see if you could predict the number of species living on an island-based upon its size. And so, as you might expect, he learned that as the size of an island grows, the diversity of life also grew, and also that it grew in a mathematically predictable way.

More precisely, Ed and Robert MacArthur found that a change in the number of species that can be supported in a habitat sustainably is related to the habitat’s size by the fourth root. This came to be called the Theory of Island Biogeography, and it has been retested many times over the years. It helps us to imagine, in principle, how much Earth you need to sustainably support biodiversity. The current amount of global protection is 15%…not good. At that level, the math would predict we’ll lose half of all Earth’s species before the end of this century.

GH – E.O. Wilson wrote, “The biosphere does not belong to us, we belong to it”. What does that reality tell us about the individual human obligation to nature and life on Earth?

PE – In Tales from the Ant World, Ed expanded on this sentiment. He said, “Nature is the metaphorical Goddess of all existence that lies beyond human control. Humanity is blessed to the extent we love her and her products from the sweet descent of her sunsets to the tantrums of her thunderstorms and from the vast empty space beyond her biosphere to the seething diversity within it, of which we ourselves are a recent chance addition. The love of nature is a form of religion and naturalists serve as its clergy.” He added, “Grant nature eternity on this planet, and we as a species will gain eternity ourselves.” So, we humans have an obligation to care for nature to the extent that we are the one species with the capacity to do so. But we also must care for it. To the extent that if we do, we are also caring for ourselves.

GH – E.O. Wilson’s answer for biodiversity protection is the Half-Earth Project, which is now the centerpiece of the E.O. Wilson Biodiversity Foundation’s action plan. What is the ambition of the Half-Earth Project?

PE – Half-Earth is a call to protect half the Earth’s land and seas in order to protect sufficient habitat for safeguarding the bulk of the world’s biodiversity. It is aligned with the Theory of Island Biogeography. The math predicts as a principle that if we protect half the Earth, we’ll be able to safeguard the bulk of biodiversity. So, as we all lean forward with a renewed awareness that our fate is dependent on the care and maintenance of our planet, we need a path to follow. The Half-Earth Project as a solution embodies hope but the key is to remember that not all places are equally effective at protecting biodiversity. So, we have been sponsoring research that guides exploration, discovery, and mapping of species, and working to democratize that information so that people can see in a new way, where we have the best opportunity to protect the most species.

Right now, countries around the world are setting global conservation targets like 30 by 30 (protecting 30% of land and seas for biodiversity by 2030), armed with information, including our research, to help guide which 30% to protect. This will lead to better conservation outcomes. Our ambition is to deliver actionable scientific contributions and evidence that supports communities in their understanding and stewardship of biodiversity and to create the foundation for an inclusive forum for community insights to ensure those outcomes.

GH – The Foundation is working to enlist corporations to commit to ‘Half-Earth’ principles. Given the penchant of business to put profit before all else, is that really possible?

PE – Yes, I think that is possible. Businesses are aware that caring for our planet is foundational to any value proposition. Businesses are now looking to organizations like ours to better understand biodiversity as they imagine how best to transform their sustainability initiatives. The science of the Half-Earth Project can give companies insight to support decision-making and fuel purpose-driven innovation.

GH – How is governance on a local, state, and national level responding to the Half-Earth Project?

PE – Inspired by E.O. Wilson’s call to action and our science, governments, environmental organizations, businesses, philanthropists and members of the public worldwide are committing to an ambitious goal to conserve 30% of land, sea, and freshwater by 2030.

These milestone commitments are grounded in the moonshot goal and solution of Half-Earth. The E.O. Wilson Biodiversity Foundation supports these commitments by sharing scientific evidence and measures. We also work to bring more diverse voices into policy discussions that are historically not considered. As the data on the Half-Earth Project Map gets finer (one-kilometer resolution), we expect it to better support regional and local community decision-making.

E.O. Wilson passed away in December last year. Recently, in honor of his birthday, a Half-Earth resolution was announced in the US Congress. Representative Don Beyer shared that, while his friend Ed Wilson passed away last year, Ed’s life work and the protection of our planet’s biodiversity lives on. The legislation honors Half-Earth and expresses the need for protecting and conserving at least 50% of US lands and oceans, and encourages diplomatic efforts to achieve this goal worldwide.

GH – What are some of the other constituencies you are enlisting to support the Half-Earth Project?

PE – Well, reaching the 30 by 30 milestone, and ultimately half the Earth, requires the voices and input of many, particularly the indigenous people and local communities who are the largest group of stewards of biodiversity.

We are committed to contributing to grassroots efforts, supporting local communities, and taking measurable corrective action against the biodiversity crisis, while also building a conservation movement that’s inclusive and equitable.

We want to build on our annual event, Half-Earth Day, and our Places and Voices of America the Beautiful discussion series. We think there is room for more inclusive forums for connecting and empowering community insights into conservation outcomes.

We are also an official observer of the United Nations Convention on Biological Diversity and the post-2020 Global Framework. We are partnered with several global conservation organizations to ensure a successful framework to protect biodiversity gets passed by the delegates of the world’s nations.

GH – Is educating children from their earliest moments in school crucial to the success of the Half-Earth Project, and how are you approaching that challenge?

PE – Engaging students early is central to the work of the Foundation. This is because we know that transformative moments of discovery, those that guide our lives in a new direction or inspire us to imagine we can make a difference in the world, are rare and often happen when we’re young and open to them.

E.O. Wilson was constantly reminding us what an amazing adventure we are on as humans, about the delight of the journey of exploration and discovery, and the opportunity we have to enrich the human experience through our lives and careers.

A core education initiative is the Half-Earth Project Educator Ambassador Program, which provides a platform and rich set of educational resources for teachers to engage each other and their students in the grand ambition of Half-Earth, and to inspire and connect students with the natural world.

We also support the education of biologists and ecologists in taxonomy (identifying and naming species) through our Chairs and Scholars program. We currently support indigenous research fellows in Gorongosa National Park in Mozambique under the direction of Dr. Piotr Naskręcki, a long-time collaborator and current Chair of the Half-Earth Project.

GH – What will it take to bring all of humanity together behind a worthy common commitment to nature and the environment we all depend on?

PE – Given the scientific consensus around the idea of half being the right target to address the extinction crisis, I believe it will take implementing Half-Earth.

E.O. Wilson is perhaps most famous for influencing our lives through his wide-ranging insight, and personally, I’ve found that’s worth paying attention to.

The idea with Half-Earth is to raise our ambition to a new level. JFK said, “We choose to go to the moon, not because it’s easy, but because it’s hard”. We set a challenging goal that will serve to organize and measure the best of our energies and skills…because it’s a challenge that we’re willing to accept and unwilling to postpone.

Ed called Half-Earth a moonshot because it’s meant to inspire us in the same way. It’s not just important conceptually, it’s important inspirationally because moonshot ambitions drive humanity and spur our collective imagination, encouraging us to lean in and do something extraordinary. And if you remember, when JFK announced the US space program, he didn’t say, you know, by the end of this decade, we’ll have made good progress towards landing a man on the moon and bringing him home. He said, by the end of this decade, we will send a 300-foot rocket on an untried mission to an unknown celestial body 240,000 miles away, and then return it safely to Earth.

So, we were challenged. We truly imagined that we could do it. By doing it, we would solve this immense problem, and we would have learned so much. So, for me, that’s what The Half-Earth Project is all about. We need that sort of deep engagement and passion that nudges us to understand that we can survive critical challenges that tap into our common humanity and nobler instincts, and that will inevitably bring us together in a common cause to protect biodiversity.


Paula Ehrlich, DVM, PhD., is the CEO of the E.O.Wilson Foundation and co-founder of the Half-Earth Project.