Aviation contributes significantly to climate change. It gives rise to about 2% of global CO2 emissions, has other physical and chemical impacts on the atmosphere that contribute to global warming, and its emissions and the other related effects are forecasted to increase rapidly. The International Civil Aviation Organisation (ICAO) recognises this fact and its 2013 Assembly has set two targets for the greenhouse gas emissions from aviation:
- A 2% global average annual fuel efficiency improvement between 2010 and 2020 (and an aspirational goal of a 2% average annual improvement up to 2050);
- Keeping the global net carbon emissions of international aviation from 2020 at the same level.
Long-term projections of aviation emissions demonstrate that in-sector reduction options and the 2% efficiency improvement will not be sufficient to keep emissions constant from 2020 onwards. The Assembly resolution acknowledges that emissions may increase due to the expected growth in international air traffic and decided to develop a global MBM scheme for international aviation.
The aim was to provide a concept for the design of the Aviation Carbon Offset Scheme (ACOS) and to overcome the deadlock that has continued for many years between developed and developing countries, hindering an agreement on instruments addressing greenhouse gas emission of the aviation sectors.
The developed ACOS concept contains the following key design elements:
- Emission threshold
- Accountable entity
- Offset requirements
- Reflection of SCRC
- Differentiation criteria
- Offset quality
Within the study, specific features for these design elements were developed.
The authors of the study discuss key design options of a Aviation Carbon Offset Scheme (ACOS), including which entity should be responsible for purchasing offsets, how requirements for purchasing offsets can be divided between the covered entities, how the diverging situations of countries can be taken into account without providing incentives to evade the scheme and what needs to be considered to ensure environmental integrity. As a result, the authors sketch out a scheme covering all countries, which takes into account differences by means of a route-based differentiation of requirements, which does not generate any revenues and which would enable the aviation sector to contribute appropriately to the global challenge of addressing climate change.
Findings of the study are published in detail by a final report which is available online via the Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety: