For Related Articles and More Information, Please Visit OCA’s Environment and Climate Resource Center Page.

Standing beside a palm oil wastewater lagoon can promote a vague sense of unease. The murky brown surface appears more molten than aqueous, blanketed in roiling bubbles that suggest the imminent emergence of a mythical beast. Plus, it stinks.

Thousands of these lagoons are spread across the tropics, and the number is growing steadily. Should you find yourself beside one, the bubbles you will see are indeed the product of subsurface life. But it’s not a hidden monster. Instead, untold trillions of microbes (and perhaps a few crocodiles) chew threw the waste stream. Each bubble is full of methane gas, leaking from these lagoons at staggeringly high rates. Toss a match onto the foamy surface and it might burst into flame.

After carbon dioxide, methane is the leading cause of a warming planet. Recently, in a paper in
Nature Climate Change, we showed that the methane produced by a typical palm oil lagoon has the same annual climate impact as driving 22,000 passenger cars. With well over a thousand (and counting) palm oil processing plants now in operation, palm oil wastewater methane emissions account for more than one-third of the warming potential of greenhouse gas release from rainforest and peat swamp destruction in Malaysia and Indonesia, where 85 percent of palm oil is produced. Already, palm oil methane leaks are equivalent to nearly 10 percent of the amount of methane arising from global natural gas production and transportation. As the industry moves toward intensification rather than land expansion, the relative importance of wastewater methane will only rise (intensification practices that drive higher yields will ultimately create richer wastewater, and in turn, more methane).