Palm oil is ubiquitous and is set to become more so over the next few decades. The oil is used in food, cleaning, and beauty products and as biofuel, so demand is set to grow rapidly. With this skyrocketing demand comes a need for the land on which to grow more oil palms—and a threat to the ecosystems currently using that land.

Currently, Southeast Asia is the oil palm hotspot, and the deforestation and ensuing damage in the region have been well publicized. But much of the future expansion may happen in Africa, introducing the likelihood of new conservation problems. A paper published in this week’s PNAS argues that there's a huge overlap between the land where oil palms could be grown and the land that houses the continent’s primates. “Large-scale expansion of oil palm cultivation in Africa will have unavoidable, negative effects on primates,” write Giovanni Strona and his colleagues.

Growth in demand, loss in habitat

The tree that provides us with palm oil (which is pressed from its fruit) is a tropical species. Currently, palm oil agriculture uses approximately 20 million hectares. One million hectares (or 10,000 km2) is about half the area of New Jersey; 20 million is about the area of Nebraska. Most of these plantations are in Indonesia and Malaysia.

The demand for edible oils, including palm oil, is set to swell over the next few decades. “Demand will probably be around 240 [million metric tons] in 2050, nearly twice today’s total,” palm oil consultant R. H. V. Corley estimated in a 2009 paper. The land needed to meet this demand will depend on factors like how much farming methods manage to improve and how much of the demand is met by growth in other vegetable oils. At worst, Corley writes, an extra 44 million hectares could be needed for palm oil; at best, with a high rate of global consumption, an extra 16 million hectares.

That’s just demand for edible oil, though. Once you factor in the demand for palm oil as a biofuel source, the need for land could increase by another 9 million hectares—or, at the highest estimate, as much as another 82 million hectares. Strona and his colleagues went with the most conservative estimate for biofuel and combined it with Corley's estimate of 44 million hectares for edible oil. Together, they mean an estimated 53 million extra hectares needed for palm oil between now and 2050.

Where will these millions of hectares come from? Given the crop's favored climates, Africa is a prime candidate. Strona and colleagues calculate that the continent has around 273 million hectares suitable for growing oil palms, although only 50 million of those hectares are “highly suitable”—the rest are either slightly or moderately suitable.

The problem is, palm oil has historically come at the expense of habitat loss. Between 1990 and 2010, writes a group of researchers in a 2016 paper, “it is estimated that 17% of the new plantations in Malaysia and 63% of those in Indonesia came at the direct expense of biodiversity-rich tropical forests.” The orangutan has been a particularly famous casualty of palm oil expansion, but the loss of habitat affects a huge array of species.

Good for palm oil, bad for primates

To get a sense for how palm oil growth in Africa would affect ecosystems across the continent, Strona and colleagues used primates as a proxy measure. They chose primates partly because they’re well studied and can serve as an indication of other biodiversity and partly because so many primate species are already under threat.

They looked at primate data from across the continent, cataloguing where different species are found and how threatened those species are. Then, they overlaid that data with the regions of palm oil suitability. There was a large overlap. The regions most suitable for palm oil are the forested equatorial regions in West and Central Africa, and those happen to be the areas with high primate diversity and many threatened species.

If palm oil cultivation were limited to just the areas where there's limited risk of harming primates, very little land would be available, the researchers point out: 3.3 million hectares overall, and only 130,000 hectares of highly suitable land. “Reconciling a large-scale development of oil palm in Africa with primate conservation will be a great challenge,” they write.

Compromise between oil palm and primate diversity will be “difficult to achieve,” says John Poulsen, an ecologist who wasn't involved with this research. “A product that we use in our everyday lives—toothpaste, shampoo, Oreo cookies—will result in a dramatic negative impact on primates in Africa.”

He hastens to point out that these results don’t necessarily spell total doom for Africa’s primates: “The loss of monkey habitat does not necessarily mean that the species will go extinct,” he explains. “Species can still be conserved in protected areas, and even outside of protected areas.” Using different data sets and other ways of measuring the importance of habitats could help to develop a more thorough picture of the risks, he adds.

But this all requires careful management, including ongoing measures to reduce the ecological impact of palm oil plantations. “History suggests that whenever there is a serious conflict between biodiversity and human livelihoods, people win out,” says Poulsen. But “African countries have the right to develop economically, and so even though it will come at an environmental cost, it is something that we have to come to terms with.”

PNAS, 2018. DOI: 10.1073/pnas.1804775115 (About DOIs).