In the Tripa forest in Indonesia's Aceh province, the rare Sumatran orangutans were dying. Flames devoured the trees, smoke filled the air and the red apes had nowhere to go. The fires had been set intentionally, to clear the land for planting oil palms—trees whose fruit yields palm oil, a widely used component of biofuels, cosmetics and food. Although the land was supposed to be protected, the Aceh governor issued a permit in August 2011 for Indonesian palm oil firm PT Kallista Alam to develop some 1,600 hectares in Tripa. In September 2012, under pressure from environmental groups, the permit was revoked. It seemed like a significant win for conservation. Yet the controversial Tripa permit was just a small part of the country's palm oil–driven deforestation crisis.

With its low price tag and long shelf life, palm oil is the cooking oil of choice in many parts of the world. The plant is a major cash crop for poor farmers in developing countries such as Indonesia, the world's largest producer of palm oil. Palm oil estates there cover an estimated 8.2 million hectares of land—an area the size of Maine—and that number is poised to skyrocket as the country prepares to double its output by 2030. Palm oil exports bring Indonesia and neighboring Malaysia $40 billion a year.

Yet this profit comes at a terrible toll. Converting forests into oil palm plantations destroys the home of not only orangutans but also such critically endangered creatures as the Sumatran tiger and the Sumatran rhino.

Moreover, the denuding of this land through logging and burning releases large quantities of the greenhouse gas carbon dioxide. Much of this forest sits on peatland, the draining and burning of which releases even more carbon dioxide than the clearing of the overlying trees does. A study published online in Nature Climate Change in October projected that with planned oil palm plantation expansion, Indonesian Borneo will release 558 million metric tons of carbon dioxide into the atmosphere in 2020. (Scientific American is part of Nature Publishing Group.)

The spread of palm oil plantations at the expense of natural forest must not continue. The most promising plan to stop it comes courtesy of the United Nations's Reducing Emissions from Deforestation and Forest Degradation (REDD) program, which would get developed countries to pay developing countries to not cut down trees. In December the annual session of the Conference of the Parties to the U.N. Framework Convention on Climate Change will convene in Doha, Qatar. The meeting presents an opportunity for signatories to finalize REDD. They should do so.

The U.S. can play a part closer to home. This past January the Environmental Protection Agency found that biofuel derived from palm oil does not meet renewable fuel standards. The announcement prompted palm oil firms abroad to hire prominent lobbyists to oppose the decision. In the absence of evidence that its science is flawed, the agency should remain firm.

Meanwhile consumers, as ever, have the power to force companies to change. KFC and Cadbury have in recent years replaced palm oil with other vegetable oils in products made for the markets in Australia, where public awareness about the environmental cost of palm oil is high. And in April the British-Dutch consumer goods giant Unilever, the single biggest buyer of palm oil in the world, pledged to purchase all its palm oil from traceable, sustainable sources by 2020.

Americans should demand transparency about where the palm oil in all consumer products comes from—and take our money elsewhere when products endanger ecosystems. Our role will become only more important as other nations, such as Brazil and Cameroon, ramp up their efforts to get in on the palm oil boom.