Risk of deforestation and potential greenhouse gas emissions from vegetable oils’ expansions for food use

The global production of vegetable oils exceeds 200 million tonnes per year, with almost 40% for food use, and around 330 M hectares occupied by oil crops. The most produced is palm (40% if palm kernel oil is included), followed by soybean oil (28%), rapeseed oil (12%) and sunflower oil (9%). Some of these oil crops, particularly oil palm plantations and soy cultivations, are among the main drivers of global land use changes (LUC) and deforestation. In particular palm oil has been one of the most highly criticized due to the link between oil palm cultivation expansion and the loss of primary tropical forests, observed in recent decades. This issue has generated two different responses in the food sector: some players decided to produce and/or use deforestation-free palm oil. Other actors chosen to replace palm oil with other vegetable oils, such as soybean, rapeseed and sunflower oil.

Considering the importance of a proper land management in view of the food-ecosystems-resources nexus, this study assesses the potential LUC and the related GHG emissions that can occur by using sustainable palm oil or replacing it with the other oils for food use. 

A methodology was developed to assess the potential GHG emissions from the LUC due to alternative oil crops expansion at detrimental of high carbon content areas, such as forests or perennial croplands, and the GHG emissions from the production process though a Life Cycle Assessment (LCA).

Under the scenario of 100% replacement of palm and palm kernel oil globally, the extra-land needed to produce the additional alternative oils was determined in their three top producer countries using yield data from literature. An expansion algorithm considering suitability and distance from roads and existing oil crops was developed to determine the potential LUC which may occur in the selected countries. The potential GHG emissions from deforestation and other LUC were calculated from the carbon stock data of the FAO Forest Resource Assessment and IPCC; the field production of the four oils was reconstructed to calculate anthropogenic GHG emissions using relevant LCA existing databases. 

Results show that deforestation-free palm oil is the less impacting in terms of GHG emissions per oil ton thanks to its far highest oil yield. Replacing sustainable palm oil with any other alternative oil is never a favourable solution (Fig. 1), entailing a potential GHG emissions increase from 0.94-0.96 Mg CO₂  per ton of palm oil replaced by sunflower oil produced in Ukraine or in Russia (where deforestation is unlikely), to 4.38 Mg CO₂ per ton of palm oil replaced by soybean oil produced in Brazil, up to 13.65 Mg CO₂ per ton of palm oil replaced by soybean oil produced in Argentina.

 

Figure 1. GHG emissions in Mg CO₂eq t^-1 from LCA (blue bars) and LUC (green bars) with 100% palm oil replacement. Based on national trends and forest policies, potential deforestation can be likely (full green), likely with limitation (dense dots), likely with offset (oblique lines), unlikely (scattered dots). Vertical lines for palm oil include deforestation.