The Conservation Letters paper summarizes the results of a case study focused on an oil palm operation in Gabon.
Poulsen and his colleagues found that the emissions from the plantation, jointly developed by the Gabonese government and agribusiness firm Olam International, could be completely offset within 25 years if oil palm development is centered on forests with lower carbon stocks and if every development set aside a portion of forest for conservation.
Industrial oil palm oil plantations in Southeast Asia have caused regional greenhouse gas emissions levels to spike and led to widespread deforestation and loss of biodiversity. So as global demand continues to grow, driving oil palm development into Central Africa, researchers are looking for ways to prevent the same scenario from playing out all over again.
Without such measures, researchers warn, converting Africa's tropical forests into monoculture palm plantations will create unsustainable levels of climate-warming carbon emissions.
The Conservation Letters paper summarizes the results of a case study focused on an oil palm operation in Gabon. "[C]onverting even previously logged forest into oil palm plantations will lead to high carbon emissions," John R. Poulsen of Duke University, an author of the study, said in a statement.
Aerial view of an oil palm plantation and a heavily logged natural forest. Photo by Rhett Butler.
Using field measurements and satellite data to calculate forest carbon stocks and potential carbon emissions at the 50,000-hectare (more than 123,500-acre) palm oil plantation in Gabon, Poulsen and his colleagues were able to test whether or not low-emissions palm oil development is feasible.
They found that the emissions from the plantation, jointly developed by the Gabonese government and agribusiness firm Olam International, could be completely offset within 25 years if oil palm development is centered on forests with lower carbon stocks and if every development set aside a portion of forest for conservation.
The researchers recommend Gabon and other tropical forest countries in Africa establish nationwide carbon thresholds of 108 to 118 metric tons per hectare and only allow forests that store less than this amount of carbon to be considered for development. Palm oil companies must also be required to set aside enough land within each plantation to offset emissions — Poulsen and team suggest that would look something like one acre conserved for every 2.6 acres developed.
"The precise set-aside ratio may vary by site, but 2.6 to 1 is generally the point at which carbon storage in the conserved forest will offset carbon loss in the rest of the plantation and achieve net-zero emissions over time," Poulsen said.
He stressed that these requirements must be mandatory — allowing industry to voluntarily adhere to these guidelines can not be an option for the team's recommended course of action to succeed.
This approach needs to be implemented by the government with careful land-use planning and strict enforcement, Poulsen said, but it can help prevent Central Africa's tropical forests from being turned into major sources of global warming emissions and perhaps even achieve carbon neutrality, thereby avoiding the emissions problems created by oil palm development in Southeast Asia.
"Although our study considers only forest carbon, and not biodiversity or other ecosystem services, we estimate there is enough low-carbon forest in Gabon to achieve net-zero emissions while still permitting the nation to meet its palm oil production goals," he said.