A new study finds oil palm plantations store less carbon than previously believed, suggesting that palm oil produced through the conversion of tropical forests carries a substantial carbon debt.
The study, conducted at two sites in Sumatra and Kalimantan by scientists at the World Agroforestry Centre (ICRAF), found that mature oil palm plantations store less than 40 tons of above-ground biomass on average over their 25-year lifespan. By comparison logged-over forests at the two sites stored 70-200 tons of carbon per hectare. Untouched forest contains even more carbon, sometimes in excess of 400 tons per hectare.
The finding that oil palm plantations store less carbon than natural forest are not a surprise, but the new figure is lower than earlier estimates. Other research has shown that palm oil produced from plantations grown in place of tropical forests incur a “carbon payback time” of decades to centuries. Carbon payback time refers to the number of years it takes for the emissions saved by the replacement of fossil fuels with biofuel to offset the carbon emissions generated when the land is converted for growing the biofuel feedstock. Since oil palm plantations are typically planted on a 25-year cycle, a carbon payback time exceeding 25 years makes palm-oil biodiesel a larger source of emissions than conventional petroleum. But payback times are considerably lower when plantations are established on grasslands and abandoned, non-forest agricultural land, where the amount of carbon stored is significantly less than in forest vegetation. Under such circumstances, palm oil can have one of the lowest carbon payback times, owing to its high productivity.
(1)Time series land cover map of site 2 estate from the study and (2) time averaged carbon-stock of oil palm at plot level. Courtesy of the authors. Click image to enlarge
Accordingly, the authors of the ICRAF study recommend that conversion should be limited to shrub and grassland areas where aboveground carbon stock is less than 40 tons per hectare. Areas with higher carbon stock should be set aside in conservation areas, allowing the forest to re-generate where it has been degraded by logging. Companies that employ this strategy may benefit from payments under REDD, a proposed climate change mitigation mechanism that would pay developing countries for avoiding emissions from deforestation. Already some plantation companies have shown interest in the concept. Last month Sinar Mas and First Borneo Group agreed to forgo conversion of peat forest in West Kalimantan on the island of Borneo in exchange for carbon payments. By some estimates, REDD could make conservation of high carbon ecosystems profitable relative to other forms of land use.
Deforestation accounts from nearly 20 percent of greenhouse gas emissions from human activities. Forest clearing and degradation of carbon-rich peatlands are the primary reason Indonesia ranks as the world’s third largest emitter of greenhouse gases despite having limited industrial activity.
Dr Meine van Noordwijk, Dr Sonya Dewi, and Suseno Budidarsono. Carbon Footprint of Indonesian Palm Oil Production: a pilot study. World Agroforestry Centre (ICRAF) July 2009.
(06/04/2009) A new paper by Oscar Venter, a PhD student at the University of Queensland, and colleagues finds that forest conservation via REDD — a proposed mechanism for compensating developing countries for Reducing Emissions from Deforestation and Degradation — could be economically competitive with oil palm production, a dominant driver of deforestation in Indonesia. The study, based on overlaying maps of proposed oil palm development with maps showing carbon-density and wildlife distribution in Kalimantan (Indonesian Borneo), estimates that REDD is financially competitive, and potentially able to fund forest conservation, with oil palm at carbon prices of $10-$33 per ton of carbon dioxide equivalent (tCO2e). In areas with low agricultural suitability and high forest carbon, notably peatlands, Venter and colleagues find that a carbon price of $2 per tCO2e would be sufficient to beat out returns from oil palm.
(06/04/2009) Indonesia’s decision earlier this year to allow conversion of up to 2 million hectares of peatlands for oil palm plantations is “a monumental mistake” for the country’s long-term economic prosperity and sustainability, argues an editorial published in the June issue of Frontiers in Ecology and the Environment.
(03/30/2009) Reducing emissions from deforestation and degradation (REDD) is increasingly seen as a compelling way to conserve tropical forests while simultaneously helping mitigate climate change, preserving biodiversity, and providing sustainable livelihoods for rural people. But to become a reality REDD still faces a number of challenges, not least of which is economic competition from other forms of land use. In Indonesia and Malaysia, the biggest competitor is likely oil palm, which is presently one of the most profitable forms of land use. Oil palm is also spreading to other tropical forest areas including the Brazilian Amazon.
(12/03/2008) Producing biofuels from oil palm plantations established on degraded grasslands rather than tropical rainforests and peat lands would result in a net removal of carbon from the atmosphere rather than greenhouse gas emissions, report researchers writing in Conservation Biology. The results confirm that benefits to climate from biofuel production depend greatly on the type of land used for feedstocks.
(11/11/2008) Scientists should compare the biodiversity oil palm plantations to other industrial monocultures, not the rainforests they replace, said Dr. Yusof Basiron, CEO of the Malaysian Palm Oil Council (MPOC), in a post on his blog. Basiron’s comments are noteworthy because until now he has maintained that oil palm plantations are “planted forests” rather than an industrial crop.
(11/07/2008) Eight developing countries threatened to file a World Trade Organization complaint against the E.U. for its proposed legislation to require imported biofuels to meet environmental standards, reports Reuters.
(09/10/2008) Plunging palm oil prices are increasing its attractiveness as a biofuel feedstock and thereby helping buoy demand for the oilseed, reports Reuters.
(08/27/2008) The British government should end subsidies for biofuels and instead use the funds to slow destruction of rainforests and tropical peatlands argues a new report issued by a U.K.-based think tank. The study, titled “The Root of the Matter” and published by Policy Exchange, says that “avoided deforestation” would be a more cost-effective way to address climate change, since land use change generates more emissions than the entire global transport sector and offers ancillary benefits including important ecosystem services.
(07/22/2008) Biofuels meant to help alleviate greenhouse gas emissions may be in fact contributing to climate change when grown on converted tropical forest lands, warns a comprehensive study published earlier this month in the journal Environmental Research Letters. Analyzing the carbon debt for biofuel crops grown in ecosystems around the world, Holly Gibbs and colleagues report that “while expansion of biofuels into productive tropical ecosystems will always lead to net carbon emissions for decades to centuries… [expansion] into degraded or already cultivated land will provide almost immediate carbon savings.” The results suggest that under the right conditions, biofuels could be part of the effort to reduce humanity’s carbon footprint.
(02/07/2008) Converting native ecosystems for production of biofuel feed stocks is worsening the greenhouse gas emissions they are intended to mitigate, reports a pair of studies published in the journal Science. The studies follow a series of reports that have linked ethanol and biodiesel production to increased carbon dioxide emissions, destruction of biodiverse forest and savanna habitats, and water and air pollution.
(01/03/2008) Biofuels made from world’s dominant energy crops — including corn, soy, and oil palm — may have worse environment impacts than conventional fossil fuels, reports a study published in the journal Science.
(10/31/2007) The Dutch government will exclude palm oil from “green energy” subsidies as growing evidence suggests that palm oil is often less sustainable than advertised.