Around 2005, North American ecologists working in Honduras' Mosquito Coast began to notice large clearings of land appearing in the normally dense jungle thickets. Of particular concern were clearings in the Río Plátano Biosphere Reserve, one of the last stretches of rainforest left in Central America and a "conservation gem" that's protected by national and international law. Determining the culprit behind this land clearing proved difficult: Though some of the indigenous groups living in Río Plátano would clear patches to grow fruit and corn, they would never do it at such scale as the ecologists were witnessing. When the ecologists asked the locals what was happening, the locals would repeatedly blame drug traffickers.
"They kept getting the response, 'Los narcos, los narcos,' every time," says Steve Sesnie, an ecologist with the Fish and Wildlife Service.
Environmental workers in the area soon realized cocaine traffickers were deforesting the Río Plátano, but not to grow coca, which comes from South America. Instead, traffickers were creating farms and ranches, to provide themselves with cover operations to mask their drug profits. Over the last decade, cocaine traffickers have been responsible for anywhere from 15 to 30 percent of the deforestation in Honduras, Guatemala, and Nicaragua, according to a new study by Sesnie and a team of geographers from universities in Ohio and Arizona. The total forest lost to recent trafficking activity "is about the state of Massachusetts," Sesnie says. The study was supported in part by a grant from the Open Society Foundations, which advocates against drug prohibition—an issue that it believes leads to violence and the spread of HIV/AIDS.
Of course, ecologists on the ground have known for several years now that cocaine trafficking, in addition to coca-growing, contributes to the destruction of tropical rainforest. But until this recent study, they didn't know the exact scope of the problem. It turns out, as Sesnie says, "It's a tremendously large area, and I think we're grossly underestimating it."
The rainforests Sesnie studied are an important carbon sink for the Earth, helping to slow climate change. They also contain much of the world's biodiversity (there are more than 400 bird species in Río Plátano alone) and provide homes and livelihoods to many indigenous Central Americans.
To quantify the forest loss, Sesnie and his team analyzed satellite images of the Central American forest, taken biweekly by NASA's Landsat craft between 2000 and 2014. The researchers then used a mathematical model to identify patches of cleared land that were likely associated with cocaine trafficking. Such land tracts were bigger than the average farmer would be able to manage himself. They also seemed to spring up abruptly on the satellite feed, in remote areas that don't usually attract such large-scale activity.
The researchers first tried to determine whether some of the land patches could be ascribed to other causes, and indeed that was sometimes the case. For example, one large clearance in Nicaragua was attributed to people salvaging wood from trees that were killed in an infestation of Southern pine beetles. But for everything else, the researchers believe cocaine traffickers to be the likely culprits. It's thought that some of the clearances are illegal airstrips for landing drug shipments, but most of them are money-laundering cattle ranches and African-palm plantations.
For Sesnie and his colleagues, the answer is for international drug and conservation policies to work together, as they argue in their study, which was published last week in the journal Environmental Research Letters. Drug interdiction, for example, can have unexpected environmental consequences. In fact, it was United States-led crackdowns on cocaine trafficking routes that used to go through the Caribbean and Mexico that first pushed traffickers into the Central American rainforest. As some of Sesnie's colleagues argued in the journal Science in 2014, "Drug policy is conservation policy." Now we have numbers to show just how true that is.