Keeping Half the Planet Human-Free to Protect Animals Would Affect Over a Billion People, Study Finds

Preserving half of the Earth's surface from humans to protect the planet's biodiversity could affect over a billion people, according to scientists.

The researchers set out to explore the human implications of what is known as the Half Earth or Nature Needs Half proposal. This idea was popularized by the biologist Edward O. Wilson in his 2016 book Half-Earth: Our Planet's Fight for Life. Such ideas attempt to solve what is known as the extinction crisis, in which 1 million species are threatened with extinction, including orangutans and rhinos.

For the study published in the journal Nature Sustainability, researchers looked at the number and distribution of people who would be affected if half of what are known as eco-regions—areas like the Central African mangroves where there is an ecological pattern because of factors like the climate or flora and fauna—were untouched by humans.

The authors found one billion people would live in Half Earth areas if the proposal was applied to all eco-regions. That is quadruple the number of people currently living in such areas, at 247 million. That would mean some 740 million people would find themselves in a protected eco-region. Most of these people would live in middle-income countries, and around 10 percent in low-income countries.

Most of the newly conserved regions would be in areas least touched by humans, but also highly developed areas like London, the authors said. This "would clearly be in conflict with human activity, raising questions about the feasibility and diverse social implications of this strategy," they wrote.

The researchers argued their work shows those who back the Half Earth project need to be explicit about what and where would be affected, and "recognize and take seriously" the positive and negative human consequences.

The research comes as world leaders are due to come up with conservation targets at the Convention on Biological Diversity in Beijing in autumn next year. Members previously pledged to protect 17 percent of terrestrial and 10 percent of marine areas by 2020.

Lead author Judith Schleicher, a conservation scientist at the University of Cambridge, commented in a statement: "People are the cause of the extinction crisis, but they are also the solution."

"We need to be ambitious given the environmental crises," she argued. "But it is vital that social and economic implications at local levels are considered if the drivers of biodiversity loss are to be tackled. The lives of many people and the existence of diverse species hang in the balance."

"Living in areas rich in natural habitat can boost mental health and well-being. In some cases, protected areas can provide new jobs and income through ecotourism and sustainable production," said Schleicher. "However, at the other extreme, certain forms of 'fortress' conservation can see people displaced from their ancestral home and denied access to resources they rely on for their survival."

"Social issues must play a more prominent role if we want to deliver effective conservation that works for both the biosphere and the people who inhabit it," she said.

Co-author Chris Sandbrook from Cambridge's Department of Geography commented in a statement: "Conservation needs strong action to protect life on Earth, but this must be done in a way that takes account of people and their needs.

"Failing to consider social issues will lead to conservation policy that is harmful to human well-being and less likely to be implemented in the first place."

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A stock image shows a mother orangutan and her baby at the Semenggoh National Park in Sarawak Borneo. These animals are among those threatened with extinction. Getty