Half of Earth ‘relatively intact’ and should be protected from human encroachment, researchers say

Around half of the ice-free land on our planet remains relatively unscathed by humans, according to a new study calling for greater protection for what is left of the natural world.

The research is based on four recent global mapping projects which detail the conversion of natural lands into space used by humans.

The colossal impacts of our species on the planet include our cities, arable farmland, and areas intensively ranched or mined.

“The encouraging takeaway from this study is that if we act quickly and decisively, there is a slim window in which we can still conserve roughly half of Earth’s land in a relatively intact state,” said lead author Jason Riggio, a postdoctoral scholar at the University of California’s Davis Museum of Wildlife and Fish Biology.

The authors said part of the aim of the research was to inform the upcoming 15th Conference of the Parties (COP15) to the Convention on Biological Diversity. The meeting was scheduled to occur in China this autumn but has been postponed due to the coronavirus pandemic. Among the meeting’s goals is to establish specific, and higher, targets for land and water protection.

At the moment roughly 15 per cent of the Earth’s land surface and 10 per cent of the oceans are currently protected in some form. However, led by organisations including Nature Needs Half and the Half-Earth Project, there have been growing global calls for governments to commit to protecting 30 per cent of the land and water by 2030 and 50 per cent by 2050.

The authors said these protections are vital for numerous reasons.“Intact natural lands across the globe can help purify air and water, recycle nutrients, enhance soil fertility and retention, pollinate plants, and break down waste products,” they said.

The value of maintaining these essential ecosystem services to the human economy has been placed in the trillions of US dollars annually.

This is illustrated, the scientists said, by how the coronavirus pandemic has revealed the importance of maintaining natural lands in order to provide animal species with sufficient space and maintain distances between some ecosystems and human activity.

The leading scientific evidence points to the likelihood that SARS-CoV2, the virus that causes the disease Covid-19, is a zoonotic virus which jumped from animals to humans. Ebola, bird flu and SARS are other diseases known to have spilled over into the human population from nonhuman animals, the team noted.

“Human risk to diseases like Covid-19 could be reduced by halting the trade and sale of wildlife, and minimising human intrusion into wild areas,” said senior author Andrew Jacobson, professor of GIS (geographic information systems) and conservation at Catawba College in North Carolina.

Professor Jacobson said planning measures which identify and apply zones to the areas best suited to urban growth and agriculture could help control the spread of human development.

Establishing protections for other landscapes, particularly those currently experiencing low human impacts, would also be beneficial, the authors said.

Among the largest low-impact areas are broad stretches of boreal forests and tundra across northern Asia and North America and vast deserts like the Sahara in Africa and the Australian outback. These areas tend to be colder and/or drier and less fit for agriculture.

“Though human land uses are increasingly threatening Earth’s remaining natural habitats, especially in warmer and more hospitable areas, nearly half of Earth still remains in areas without large-scale intensive use,” said co-author Erle Ellis, professor of geography at the University of Maryland-Baltimore County.

Areas having low human influence do not necessarily exclude people, livestock or sustainable management of resources. A balanced conservation response that addresses land sovereignty and weighs agriculture, settlement or other resource needs with the protection of ecosystem services and biodiversity is essential, the authors said.

“Achieving this balance will be necessary if we hope to meet ambitious conservation targets,” added Professor Riggio. “But our study optimistically shows that these targets are still within reach.”

The research is published in the journal Global Change Biology.