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Airlines’ biofuel ambitions must not increase emissions


If international aviation were a country, it would be a global top ten carbon emitter, with emissions expected to triple or quadruple by 2040. This is why the International Civil Aviation Organization (ICAO) has agreed to cap net carbon emissions from international aviation at 2020 levels.

Airlines are planning on filling up with biofuels to meet their climate change goals, but will aviation biofuel policies be based on science or fantasy? © Mika MeskanenAirlines are planning on filling up with biofuels to meet their climate change goals, but will aviation biofuel policies be based on science or fantasy? © Mika Meskanen

ICAO aims to achieve this goal through technical and operational measures; carbon pricing through market-based measures (MBM’s); and biofuels. Many airlines see biofuels as a “silver bullet” for meeting their carbon goals.  Already over 40 airlines have flown over 600,000 biofuel-powered flights.

Biofuels: aviation’s silver bullet?

ICAO established the Alternative Fuels Task Force (AFTF) to answer the key question: how much do biofuels actually reduce greenhouse gas (GHG) emissions? The AFTF is close to finalizing its answer. EDF, WWF-UK and our colleagues in the International Coalition for Sustainable Aviation are working to secure an MBM of high environmental integrity for international flights. Getting biofuel carbon accounting right is vital. If biofuels reduce carbon pollution, then airlines’ obligations under the MBM will decrease. But if biofuels increase carbon pollution, then airlines’ MBM obligations will increase.

Land use change and the need for additional carbon

ICAO assumes that biofuel combustion is carbon neutral, but the scientific community increasingly challenges this assumption, for two main reasons:

  1. Increasing biofuel demand doesn’t necessarily lead to enough additional plant growth to offset the combustion emissions.
  2. The “carbon neutral” approach ignores the warming effect of CO2 emitted by burning biofuel.

For biofuels to reduce emissions, producing and burning biofuel must either result in fewer emissions or greater carbon absorption by plants than would have otherwise occurred. This is called “additionality.”

Biofuels can achieve “additionality” if they use wastes that would otherwise burn or decay, or if the biofuel production increases the carbon stock on the land where biofuel feedstocks are grown.

Biofuel production is not “additional” when it uses existing crops, or when it leads to land use change (LUC) – directly or indirectly destroying ecosystems to make room for biofuel crops.

Direct land use change (DLUC) occurs when existing ecosystems are replaced by biofuel plantations; for instance, when farmers slash rainforests to make way for palm oil plantations to supply biofuel. This releases huge stores of carbon that could take hundreds of years to recoup.

Indirect land use change (ILUC) occurs when using existing crops for biofuels triggers ecosystem destruction elsewhere. For example, if a maize farmer that originally sold to food producers starts selling to biofuel refiners, maize supply for food could go down and prices could go up. Higher prices could encourage others to create new maize farms to meet the supply shortfall. The original farm will not reduce net atmospheric carbon emissions by selling its already existing crops to a new buyer. The new farms could increase net atmospheric carbon by chopping down native vegetation to make room for new crops.

LUC-related emissions have been shown to outweigh the carbon savings of certain biofuels.  Therefore, AFTF’s biofuel carbon accounting formula must account for the CO2 emitted from direct and indirect land use change (DLUC and ILUC).

Aviation industry commitments graph to 2050 © IATAThe blue section in this graph shows the aviation industry sees a big role for biofuels, so it’s vital ICAO gets the carbon accounting right © IATA

Sustainability safeguards

Biofuels must only be sourced from areas where the GHG emissions and removals in the land sector are measured, reported and verified in accordance with internationally recognized standards, and where regulations exist to protect vulnerable ecosystems. Certification schemes can guard against many of the potential negative impacts of biofuel production, including direct land use change. The Roundtable for Sustainable Biomaterials (RSB) scheme is currently being updated with an additional module to address ILUC risks too.

The best way to ensure additionality is to base biofuel carbon accounting on what the atmosphere sees:

  • Count the GHG emissions of all fossil fuels and biofuels burned in an aircraft engine;
  • Count additional carbon sequestration or avoided emissions in biofuels’ production and feedstock growth phases that would not have otherwise occurred;
  • Once verified, these additional carbon reductions could be counted towards offsetting aircraft combustion emissions.

ICAO must also avoid double-counting: If emissions reductions from using biofuels count towards international aviation’s goal of carbon neutral growth from 2020, then those emissions reductions cannot also count towards a country’s national emissions reduction goals.

A realistic role for aviation biofuels

Most land where biofuel crops can grow is already home to important ecosystems.  Moreover, biofuel crops need a lot of land to be scalable, competing with increasing demands for land for other uses.

Thus, while low-emitting biofuels can play a role in reducing international aviation emissions, they can’t play the main role.

ICAO should remain focused on its other measures: establishing a robust MBM with maximum environmental integrity, and continued technical and operational improvements. Coupled with full carbon accounting for biofuels, these measures can ensure that ICAO learns from the science, and from past policy experience, to incentivize only low-risk biofuels with undisputed carbon savings.

This blog is written by James Beard, WWF-UK and Rafael A Grillo Avila, Environmental Defense Fund.

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