A mere five countries contain 70% of the untouched natural ecosystems left in the world, and will only continue to survive with urgent international cooperation, according to researchers.

Scientists at the University of Queensland (UQ) and the Wildlife Conservation Society (WCS) warn that Earth’s last remaining wildernesses are at risk of “disappearing completely.” Their report, published in the journal Nature on Wednesday, maps the five countries — Russia, Canada, Australia, the United States, and Brazil — harboring the last totally natural habitats.

The researchers defined “wilderness” as territory free of “human pressures” — including settlements, farmland and transportation infrastructure — over an uninterrupted range of 10,000 sq. km. (3,861 sq. mi.). The survey excludes Antarctica and the open seas, but the authors note that marine regions “free of industrial fishing, pollution and shipping are almost completely confined to the polar regions.”

They found that changes to the Earth’s surface have been dramatic as well as rapid: 77% of Earth’s land area is now used for faming, up from 15% just 100 years ago.

Protection of the remaining untouched areas could be critical to mitigating the effects of climate change, according to the report’s authors. Forests and seagrass meadows are important reservoirs of carbon. Other wildernesses can act as a buffer against extreme weather events, including by absorbing some of the impacts of extreme rainfall or natural disasters like tsunamis.

The study comes in the wake of an alarming report from the World Wildlife Fund this week, which estimated that human activity has decimated wildlife population by 60% in the past four decades. An earlier WWF report this year warned that 50% of wildlife and 60% of plants in the world’s most biodiverse forests could be at risk of extinction over the next century.

The Nature paper’s authors warned that Earth’s last wilderness will remain intact “only if it is recognised within international policy frameworks.” They also called on the five key countries containing the intact ecosystems to limit new industrial activity.

The report comes ahead of the Convention on Biological Diversity this month, which aims to forge a plan for biodiversity protection beyond 2020.

“Already we have lost so much,” the report says. “We must grasp these opportunities to secure the wilderness before it disappears forever.”

Get The Brief. Sign up to receive the top stories you need to know right now. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Eli Meixler at eli.meixler@time.com.