The first truly global scheme aiming to mitigate international aviation's greenhouse gas emissions is soon to be implemented; this requires airlines to start to monitor their emissions on international routes from the coming year.
Developed by ICAO, it is known as CORSIA – the Carbon Offsetting and Reduction Scheme for International Aviation. Its intent is to enforce measures that mean that international aviation will incur the environmental cost of its activities. However, since its approval in 2016, the scheme has faced more criticism than praise. So, where does the scheme potentially fail to deliver results and why should ICAO stick to tight rules?
CORSIA is focussed on restricting International Aviation's sectoral emissions at 2020 levels, largely through the process of purchasing carbon offsets. Hence, the sector is expected to start compensating for the environmental effects of its growth from 2021 onwards. However, CORSIA remains voluntary for ICAO member states until 2027 limiting the scheme's comprehensiveness. Currently, states voluntarily participating account for 76% of international traffic. The question of whether China (representing 12%) will join too is still unanswered.
Nevertheless, the scheme is supposed to align with the UN Paris Climate Agreement (PA), which establishes the global target of limiting temperature rise to no more than 2oC (requiring urgent action from all sectors).
Here we come to the first problem - aviation is predicted to have a stable and relatively high average rate of growth of approximately 4.5% for the next 30 years (the highest across all transportation sectors), and thus will continue to produce emissions in increasing volumes. As the CORSIA scheme lacks ambition beyond offsetting emissions, the compatibility of its goals with the Paris targets could be deemed inadequate. Furthermore, since it is a voluntary scheme, campaign groups suggest that towards 2035 it will only be able to cover 75% of the industry's emissions surpassing 2020 levels.
Another problem of the scheme lies in the integrity of its carbon offsets. Past experience suggests that such offsets might not be the most effective way of achieving environmental targets as they are often subject to various problems including double counting (i.e. the offset may happen anyway for other reasons); their overall effectiveness in delivering emission reductions can therefore be overestimated. CORSIA can achieve carbon neutrality only if investments in offsets trigger the emission reductions that would not have happened otherwise.
Whether the criteria for offsets that ICAO plans to deliver as part of CORSIA will be stringent enough to drive additional reductions also remains uncertain since the decision has been postponed. Concerns are increasing, since some countries are lobbying for inclusion of the current (cheaper) offsets coming from the UN's Clean Development Mechanism (CDM) projects whilst others are calling for pre-2016 projects to be disallowed.
Other causes for concern arose after ICAO indicated its intention to scale down the sustainability criteria for biofuels used under the scheme. Of the previous 12 sustainability criteria, biofuels would be required to satisfy only two: 10% savings in CO2 emissions from biofuels (beyond fossil fuels) and a ban for biofuels cultivated on deforested lands. Then in June of this year ICAO added further salt to the wounds of environmental organisations by approving acceptability criteria for low-carbon fossil fuels in the scheme. This means that fossil fuels produced in refineries running on renewable electricity or on enhanced oil recovery technology could have lowered offset obligations.
ICAO finds itself in the difficult position where it has to deliver an environmentally effective scheme whilst at the same time satisfying the needs and requirements of a wide variety of states with different socio-economic situations. It's quite possible that additional compromises may therefore be accepted on offsets and biofuels. A further weakening of the scheme might compromise its main purpose, that is to deliver an efficient mechanism that would curb the emissions from aviation. Failure to achieve this could result in dissatisfaction from some states and the EU (in particular) that may lead them to propose more ambitious regional targets and/or opt out of the scheme altogether. Should this be the case, the whole point of having uniform international global measures such as CORSIA may be void.