To foster technology development, ICAO regularly sets technology goals, with the purpose of providing stretch yet reasonable targets for industry R&D to aim at, in cooperation with States. These ICAO technology goals are developed by panels of independent experts, which ensure transparency and involvement from all stakeholders.
An Independent Expert Review specifically focused on CO2 emissions was delivered in 2011, as registered in ICAO Doc 9963 - Report Of The Independent Experts On The Medium And Long Term Goal For Aviation Fuel Burn Reduction From Technology.
The latest set of technology goals for CO2 emissions is detailed in the ICAO Doc 10127 - Independent Expert Integrated Technology Goals Assessment and Review for Engines and Aircraft (2019). This was the first time that ICAO developed technology goals for noise, local air quality and CO2 emissions in an integrated manner, with full consideration of the interdependencies between the technologies. More details on these goals are provided here.