In 2012 a villager walking through the forest in Mozambique’s Niassa Reserve came across a young male lion caught in a poacher’s snare. The lion lay on the ground, a noose of thick wire squeezing its lower torso. Conservation workers later freed the animal, but most lions are not so lucky. “Poaching has been a major issue over the years,” says Natasha Ribeiro, who has studied illegal hunting in Niassa Reserve and is a forest ecologist at Eduardo Mondlane University in Mozambique.

She and other experts fear that bushmeat snaring and other threats to lions—including habitat loss and retaliatory killings after the big cats prey on livestock—will only get worse as the human population in Mozambique and many other African countries continues to grow rapidly in the next few decades. Most of the world's lions live in Africa, with a total of 20,000 estimated to remain across the continent. Effective conservation solutions, such as building fences and adding rangers to antipoaching patrols, are costly and severely underfunded.

Now Ribeiro is part of a group of researchers who hope to raise money for such efforts by adapting an approach that has proved successful in funding conservation projects in northern Australia. It centers on the use of one of humankind’s oldest tools: fire. Intentionally starting grassland fires early in the dry season lets land managers achieve a “cooler” burn that consumes less woody fuel overall but still removes enough vegetation to reduce unplanned high-intensity fires that often break out later in the season. The upshot is fewer carbon emissions in the air and more carbon stored in the soil. And both outcomes can be measured and sold as offset credits on the global carbon market. The research team outlined its lion-centric fire management plan in a recent preprint study that has been released but not yet reviewed by experts.

In Australia, such programs have helped landowners, including many who are Indigenous, secure government contracts to abate about 14 million metric tons of carbon over an average of eight and a half years. This would generate an estimated $126 million for land management. A 2018 study of global opportunities for reducing emissions through early-season controlled burns found such an approach could work in 37 countries, 29 of them in Africa. The estimated annual carbon abatement potential is about 90 million metric tons—equivalent to taking about 19.5 million passenger cars off of U.S. roads.

For Africa’s lions, help cannot come too soon. Myriad pressures are depleting the population, and the most intense is the growing bushmeat trade. Local residents set snares in reserves to catch small, wild herbivores. This reduces the lions’ food supply, and the traps occasionally kill the cats outright. Retaliatory killing is also a growing threat, even when lions are not the aggressors. Luke Hunter, executive director of the Wildlife Conservation Society’s (WCS’s) big cats program and one of the co-authors of the new preprint study, estimates African lions kill fewer than 200 people a year and a few thousand livestock. But they are scapegoated for the deaths of many more domesticated animals because they often feed on the carcasses of those that died by other means, he says. A third problem is poaching for lion teeth, bones and other body parts.

Add it all up, and lions’ numbers have plummeted by 43 percent globally, according to an analysis by the International Union for Conservation of Nature’s Red List of Threatened Species that spanned 1993–2014 and represented 47 protected lion populations across the species’s range. “It’s a massive, massive decline,” says Hunter, who co-authored a 2015 study that also showed lions’ numbers dropping and another one in 2018 that estimated the cost of shoring up the underfunded protected areas, where most African lions live, as a whopping $1 billion per year.

But the new paper finds that, depending on the pricing used, funds ranging from $60 million to $1.7 billion could possibly be raised by selling carbon credits to companies looking to offset their greenhouse gas emissions. Hunter, Ribeiro and their colleagues estimated that each of Africa’s protected areas, depending on size, could use controlled burns to earn an average of between $1.5 million and $44 million annually in the carbon-offset market. That money could then be used to hire local residents as wildlife rangers and to pay for things such as constructing fences and educating residents about how to coexist with predators. “This approach is much bigger than saving the lions,” says the study’s lead author Tim Tear of the Biodiversity Research Institute. “It’s about reversing land degradation, increasing biodiversity, slowing climate change and helping Indigenous people. It literally ticks all the boxes.”

The idea of bringing widespread fire management for carbon credits to Africa’s savannas originated with ecologist Geoff Lipsett-Moore, who helped set up a successful program in a protected area in Australia’s Northern Territory a decade ago. Lipsett-Moore helped bring in Indigenous Australian land managers, who began to purposely set and extinguish fires early in the dry season—just as their ancestors once did. This has reduced late-season burns in the protected area from 36 percent to less than 5 percent. And doing so not only raises money through carbon credit sales (close to $400,000 in the first two years); it also buoys plants and wildlife that evolved with the formerly common early-season fires. The return of early burns, for instance, is stimulating more production of seeds that nourish the threatened Gouldian finch, according to 2018 findings.

Still, fire ecologist Jeremy Russell-Smith of Charles Darwin University in Australia, who helped set up Australia's first and most successful fire-management-for-carbon-credits program, is not sure similar successes can be replicated in such a different environment. He says gentler blazes might not promote the same kind of massive, open grasslands required by larger animals in some African habitats.

Russell-Smith, who was not involved in the new study, also questions whether it is possible to increase soil carbon in the Miombo—a vast, multinational region that includes Niassa Reserve and is home to many African lion populations. The Miombo’s soil is sandy and nutrient-poor, much like soil he had earlier evaluated in northern Australia. He found that, even with an early-season fire regime, this area’s soil did not store carbon well.

Most of Australia’s savanna-fire-management programs, however, focus only on carbon emissions reduction—not soil carbon sequestration. And a 2014 analysis in Zambia, carried out by Mark Ritchie, a biologist at Syracuse University and a member of the new study’s team, showed that changing the fire regime would allow greater soil carbon storage in certain types of Miombo terrain. In sandy soils, Ritchie says, plants grow longer roots, so soil sampling must go relatively deep—up to a meter—to find stored carbon there. Many studies, he adds, only sample the top 20 to 30 centimeters of sandy soil, as is typical for measuring carbon stored in clay or other soil types.

Ritchie also developed a soil-carbon-sequestration program in Kenya that encourages cattle and camel herders to systematically rotate livestock grazing areas, allowing grass to recover and store carbon. This effort recently enabled the Kenya grazing program to sell more than two million carbon credits, he says. Poaching of Grevy’s zebras, reticulated giraffes, gerenuk antelope, and other threatened and endangered species has since dropped in the area. “In Africa, it’s amazing, when you take these incredible pressures off the land, how well it responds,” he says.

Ritchie and the others are eager to pilot fire-shifting efforts in Niassa Reserve, which they chose for its biodiversity and large area (carbon sequestration is more effective on a large scale in wilderness regions)—as well as its big, unfenced lion population. Ribeiro, who has studied Niassa’s fire ecology and the fire-use practices of local villagers, says there is no time to waste. She notes that the human population of Niassa has tripled in the past 15 years. “From the point of view of the lions,” she says, “they will always lose if we do nothing, because as the people are increasing, their habitat shrinks. It shrinks and shrinks and shrinks.”