Rewilding

In 2002, an aristocratic English couple did something radical. Their agricultural estate, Knepp Castle, had failed to turn a profit for decades, so they wrote to the British government to say they had made a decision.

The couple, Charlie Burrell and Isabella Tree, were going to let their land go back to the wild. Completely wild. They would reintroduce deer, untamed exmoor ponies, longhorn cows similar to the extinct auroch, and pigs that resembled wild boars. Some indigenous grass was resown. Beyond that, they resolved not to interfere with nature’s process.

Eighteen years on, the estate is home to a cornucopia of endangered flora and fauna in a country where 15% of wildlife species are under threat of extinction. The reintroduced wild animals churned up land that had long been carefully manicured by humans, creating opportunities for new plants to grow. The plants, in turn, attracted rare insects, which became prey for endangered birds.

Burell and Tree are at the forefront of a global movement. While some scientists try to tackle climate change with creative ideas like ocean fertilization or using space mirrors to reflect away sunlight, rewilders say we should also employ a simpler way to help fix the planet: Let the earth take care of itself.

60%: Decline in global animal populations between 1970 and 2014

26: Species of beetle found in one cowpat at the Knepp Castle estate

25%: Area of the planet substantially free of human impact

1,900: Football field-sized areas reforested daily in Europe from 2005-2015

37%: Carbon mitigation needed to hit 2°C targets that natural climate solutions could tackle

30 million hectares (74 million acres): Hectares of marginal European farmland expected to revert to forest between 2012 and 2030

8: Cross-border conservation areas created in southern Africa since 1997

3: “Cs” of rewilding, according to the biologists who popularized the concept: cores of protected land, corridors between them, and carnivores to maintain population balance

For some, the term “rewilding” is as controversial as its practices. In a 2016 paper titled “Rewilding is the new Pandora’s box in conservation,” one group of scientists said many “too often play too loose” with its terminology.

The term was popularized in the late 1990s by two American biologists (pdf), who argued that conservation shouldn’t mean just conserving an area of land but bringing back predators that kept the ecosystem functioning in its natural state. Many projects that claim the title rewilding do involve returning a predator or large herbivore to help regulate a space. But, depending on who you talk to, rewilding can also mean planting trees or just leaving the land alone to do its thing.

The “re” in the term is hotly contested, with its implication that land so long curated by humans can ever really be returned to its original state. So, indeed, is the “wild” part. Can parcels of land that are ultimately still overseen by humans, often without apex predators, really be considered wild?

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British farmers receive around £3 billion ($3.7 billion) in EU subsidies. With Britain departing the bloc, the nonprofit Rewilding Britain says the government should repurpose that money by paying those farmers £1.9 billion to return their land to the wild. Downing Street later earmarked a third of that amount in a “Nature for Climate” fund.

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In the 1970s, Dutch ecologists began persuading their government to introduce wild animals on a plot of reclaimed former sea then being drained for use by industry. The area, Oostvaardersplassen, became the birthplace of rewilding in Europe long before the term was coined in the 1990s. Like Knepp, it has become home to a plethora of rare animals, including a pair of white-tailed eagles, which were near extinction in the 1980s.

Despite its conservation successes, the project holds a controversial place in Dutch public opinion for its extreme non-interference in the animal life cycle. With the space too small to house predators, its herbivore populations skyrocket in warm years, but a cold winter can see mass starvation. Between 2017 and 2018, the number of red deer, Konik horses, and Heck cattle fell from 5,230 to 1,850. The vast majority were culled to stop their suffering.

The PR nightmare of emaciated animals beamed onto television screens is compounded by Oostvardersplassen’s commitment to leaving their corpses to rot on the ground. Research shows the practice has great benefits for plants and other wildlife, which feed on the carcasses, but the combined spectacle enrages activists—who have thrown hay bales over the reserve’s fences. Scientists who support the project have said the controversy comes from “a small group of people have made a tremendous noise, especially horse owners.” But in 2018, the local council ordered that about 1,000 deer be culled and most of the horses relocated, following a report arguing total herbivore numbers be capped at 1,500 to stop starvation.

“Some people say the ecosystem is dying. Some people, like me, say the ecosystem is just coming alive,”

—Han Olff, ecology professor at the University of Groningen, on the controversy over death at Oostvaardersplassen

1861: The Fontainebleau forest in France is declared an “artistic reserve,” the world’s first nature reserve.

1924: At the suggestion of ecologist Aldo Leopold, the US designates its first official wilderness area, the Gila Wilderness in New Mexico.

1983: Dutch ecologist Frans Vera buys Heck cattle with the aim of bringing them to Oostvardersplassen.

1990: A Newsweek article uses the word “rewilding,” believed to be the term’s first mention in print.

1992: Dave Foreman, founder of the radical environmental group Earth First!, begins using the term “rewilding.”

1995: Wolves are reintroduced to Yellowstone—and later credited with “saving” the park.

1997: The Peace Parks Foundation is launched by Nelson Mandela, with the aim of combining conservation efforts in areas that cross African borders.

1998: US biologists Michael Soule and Reed Noss popularize the concept of rewilding.

2005: A team of conservationists introduces the concept of “Pleistocene rewilding,” a proposal to create “vast ecological history parks” in North America with elephants, lions, camels, and other large mammals.

Partial rewilding can be a great farming tool. One English farm manager—Jake Fiennes, brother of actor Ralph Fiennes—stopped growing food on 20% of his estate’s land and found production increased so much in the remaining area that it cost the estate nothing.

Three years ago, a study led by the Nature Conservancy seemed to vindicate those who argue rewilding—in the broadest sense of the word—is not just a project for fringe conservationists, but potentially critical for humanity as a whole. It found that “natural climate solutions” could sequester more than a third of the carbon needed by 2030 to keep earth on track to limit global warming to 2°C.

Some solutions, predictably, focus on reforesting and tree planting. But others are counterintuitive. In Australia, funding indigenous groups to return to millennia-old practices of setting fire to land has helped preempt more dangerous, carbon-spewing wildfires. Elsewhere, conservationists rail against tree planting on land that wasn’t previously forest. Trees often fail to take root in such places, and, in Canada and China, these schemes have reportedly caused wildfires, drained groundwater levels, and harmed natural ecosystems.

Instead, many activists say we should focus on a less glamorous terrain: the humble bog. Peatlands are particularly treasured—they cover just 3% of the Earth but store twice as much carbon as all the world’s forests combined. When damaged, however, they can be deeply harmful. Drained peatlands are extremely flammable, and cause almost 6% of human-driven carbon emissions. Around 15% of global peatlands have been drained and more are rapidly disappearing, but efforts to restore and conserve them are starting up everywhere from Germany to Borneo.

Guardian columnist and activist George Monbiot argues that megafauna like elephants and rhinos, which disappeared from Europe after the Ice Age, should return to the continent.