With Earth’s wildlife now facing an extinction crisis, a group of economists and scientists is hoping to persuade governments that it pays to protect nature. Specifically, expanding areas under conservation could yield a return of at least $5 for every $1 spent just by giving nature more room to thrive. That in turn would boost agricultural and forestry yields, improve freshwater supplies, preserve wildlife and help fight climate change – all of which would boost global economic output on average by about $250 billion annually, the group of more than 100 researchers argues in a paper published Wednesday. The work represents one of the most comprehensive studies of the potential economic benefits from protecting nature – a research area fraught with best-guess estimates on the monetary value of animals, plants and ecosystems left intact. Released as the United Nations lobbies governments to set aside 30% of their land and sea by 2030, the report aims to challenge the notion that conservation is costly. “You cannot put a price tag on nature, but the economic numbers point to its protection,” said Anthony Waldron, an ecologist at the University of Cambridge who lead the group examining the economic implications of designating a third of the Earth as a nature reserve. Others question how precise accounting for nature’s economic contribution is even possible, said Bram Büscher, a political scientist at Wageningen University & Research in the Netherlands. “What are two ducks worth? And would these ducks in the U.S. be the same as in Latin America? And how would you compare those things, and what would be their role?” Büscher told Reuters. Leaning too heavily on economic arguments could also backfire, if governments end up opening areas deemed valuable to the highest bidders, warned Julia Steinberger, an environmental economist at the University of Leeds. “All it takes is one lobbyist to come along and say ‘This programme is no longer economically viable,'” Steinberger said. “That’s the risk we see when we tie environmental protection to economic performance.” But even a rough estimate of nature’s economic value is better than nothing, given the scale of what is at stake, the report’s authors argue. Scientists estimate that at least a million species are facing extinction in the next few decades, largely due to human-driven activities including habitat loss, pollution and climate change. Hoping to halt the global die-off, 30 countries are already backing a draft document pledging to conserve 30% of the Earth’s surface by 2030, which will be discussed at the U.N. Biodiversity Convention postponed to next year in Kunming, China. Currently, about 15% of the Earth’s land and 7% of the ocean has some degree of protection. A 30% conservation goal, aside from producing natural resources like fish stocks and timber, would also help to guarantee healthy ecosystems that provide an additional $350 billion a year in services that are essential to life, including filtering water, clearing air pollutants or preventing coastal erosion, the report said. Such a goal would require an average annual investment of roughly $140 billion by 2030, the researchers estimated. Currently, about $24 billion is spent globally per year on protecting natural areas, they said. “The well-being of humanity and global economic prosperity depends on us fixing our broken relationship with nature,” said report co-author Enric Sala, an ocean explorer in residence at National Geographic Society. The report said that a major expansion in protected areas would have to be managed carefully to ensure that the economic benefits were spread evenly throughout populations. But first, countries have to join the effort. And even then, compliance is not guaranteed. Despite having more than 190 countries pledge to fight climate change under the 2015 Paris Agreement, emissions of heat-trapping gases continue to rise. Nevertheless, with some U.S. states pledging to reduce greenhouse gas emissions, there is growing interest in finding ways to account for the economic benefits provided by forests and other ecosystems, said economist John Talberth at the Center For Sustainable Economy in Portland, Oregon. Understanding these economic benefits can also help policymakers decide, for example, whether a forest can be felled for timber or better left untouched to absorb carbon dioxide and support wildlife or water cycles. “The climate crisis has put a foot on the accelerator of getting this done,” Talberth said.”