The International Civil Aviation Organization (ICAO) on Friday adopted new, more stringent standards on carbon emissions and noise that could impact a range of American type certification projects.
As of 2031, ICAO will require new aircraft type designs to meet a 10 percent stricter carbon dioxide (CO2) certification standard than the one in effect since 2017. From 2035 on, new deliveries of aircraft in production will also need to meet a “complex, more stringent” emissions standard, categorized by their maximum takeoff mass.
In addition, the organization in 2029 will implement harsher noise requirements that cover both subsonic and supersonic aircraft. It will raise the bar by 6 decibels for larger aircraft and 2 decibels for smaller ones.
The effective date of the new standards is August 6. By 2027, they will take effect globally.
The specific limits will be published in ICAO’s update Annex 16, Volume III. The organization said it will provide “detailed implementation guidance and comprehensive documentation on both the environmental benefits and regulatory impacts of the changes.”
Though regulators such as the FAA and European Union Aviation Safety Agency (EASA) have the leeway to create regulations tailored to their airspace, states are required to align their internal rules with ICAO standards. Often, doing so is advantageous because it simplifies the means for U.S. exporters to comply with requirements in other countries.
The FAA uses ICAO’s CO2 certification database, which was also adopted by EASA. Its Part 36 is largely harmonized with the ICAO noise limits.
ICAO adopted the carbon dioxide certification standard in 2017 as the first global technology standard for CO2 emissions for any sector. Under the new standard, essentially, the existing CO2 limit for new aircraft designs will become the new limit for in-production designs, while the bar for new entrants will be substantially higher.
Though the updated provision will not take effect until 2031 for new aircraft, it could send manufacturers—particularly those with active type certification projects—scrambling to meet the new requirements. Others may be well positioned. Boeing claims its 777X will produce 20 percent fewer emissions than the models it replaces.
The CO2 limit is calculated using a range of factors, including fuel consumption rate, maximum takeoff mass, and type of propulsion system.
ICAO’s change to noise limits could also be impactful. As soon as this summer, the FAA will oversee testing of a range of electric aircraft, from electric vertical takeoff and landing (eVTOL) air taxis to regional models. If these vehicles prove to be quieter than helicopters, as their manufacturers claim, they could become attractive to operators looking to cap their noise footprint.
At the other end of the spectrum, stricter noise standards could hinder a company like Boom Supersonic. Boom claims its Overture will be the first civil supersonic aircraft since Concorde, cruising at about Mach 1.3 over land and generating sonic booms. However, the company in 2025 demonstrated the ability to prevent those booms from reaching the ground, suggesting Overture could meet the updated limits.
In June, the White House directed the FAA to lift its 52-year ban on supersonic commercial flight over land, in part because of Boom’s efforts. Simultaneously, NASA is testing its X-59 quiet supersonic demonstrator, which it intends to fly over U.S. communities to gauge their response to noise. Data from the community survey will be shared with the FAA, ICAO, and other regulators.
