Expanding millions of hectares of Brazilian land to
produce palm oil for food or for renewable, clean-burning biodiesel
could result in extremely high emissions of carbon dioxide (CO2) unless strict controls are put in place.
This is according to a new study published today, 14 November, in IOP Publishing's journal Environmental Research Letters, by a group of researchers from the University of California, Davis.
The researchers found that unless the oil palm plantations are
strictly confined to previously deforested land and not allowed to spill
over into conservation or indigenous areas, the total amount of CO2
emissions from biodiesel, made from palm oil produced in that region,
may exceed the carbon intensity of petroleum diesel, which biodiesel
intends to replace.
Focussing on the Brazilian region of Pará, the researchers employed a
"bottom-up" model to arrive at their conclusions, which accounted for
the complex interactions of drivers at the regional and local scale that
can influence emissions, such as neighbouring land use, access to
infrastructure, the distance to local markets and the suitability of
land.
Brazil has drastically increased its production of biodiesel over the
last decade. In 2006, the country produced 69 million litres of
biodiesel; today, it produces close to 3 billion litres, the majority of
which is produced from soybean oil.
Oil palm has become an increasingly attractive crop for the
production of biodiesel as it has a much higher yield than other crops,
requires barely any new technology to produce and harvest, can grow in
poor soil conditions and is very labour intensive -- ideal for job
creation and security.
The Brazilian government has recently approved a bill to expand 4.3
million hectares of previously deforested land to oil palm plantations
and has found over 30 million hectares that may be suitable for the
expansion, the majority of which are in the northern state of Pará.
In their study, the researchers created three different scenarios of
land use change over a 30 year period in Pará and used a land use change
model and spatially explicit carbon maps to assess the amount of CO2 emissions that may occur as a result of each scenario.
In the first scenario, only a third of plantations occurred on
previously deforested land with the rest occurring on conservation and
indigenous areas; in the second and third scenarios, a larger proportion
of plantations (46% and 78%, respectively) occurred on previously
deforested land.
In each of the scenarios, 22.5 million hectares of land were
converted, creating 29 billion gallons of biodiesel each year. In the
first and second scenarios, where there was little or no enforcement,
the land use change resulted in 84 and 60 grams of CO2 emitted per megajoule (gCO2e/MJ), respectively -- the European Commission has rated the carbon intensity of diesel as 83.8 gCO2e/MJ.
The researchers point out that if the extraction, refinement,
transport and actual combustion of the biodiesel is taken into account
and added to emissions from either of these two scenarios, the total
carbon intensity of biodiesel will greatly exceed that of diesel.
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