Starting Jan 1, 2019, most airlines flying international routes will begin monitoring their fuel and carbon emissions as part of the landmark agreement brokered two years ago by the International Civil Aviation Organization (ICAO).
Airlines had called on ICAO to approve the standards which they need to prepare for the agreement that officially goes into effect in 2021.
"This now allows governments and industry to make final preparations for implementation before the CO2 emissions monitoring and reporting obligations commence in January 2019," Michael Gill, executive director of the cross-industry Air Transport Action Group (ATAG), said in a statement.
The 2016 ICAO deal requires airlines to limit their emissions or offset them by buying carbon credits from designated environmental projects around the world.
The new standards, approved by a majority of ICAO's 36-member governing council, including the United States, give governments a technical guide on how to compile airlines' emissions and how much the carriers will need to offset.
"This is a very significant step, but there are still important details needed to be filled in," Annie Petsonk, international counsel for the Environmental Defense Fund, said in a telephone interview.
ICAO has yet to finalize the specific criteria for fuels allowed under the agreement, she said. In principle, fossil fuels can qualify, but they will have to meet the agreement`s standards.
Complying with the agreement is estimated to cost airlines less than 2 percent of industry revenue. The deal is voluntary for the first five years and becomes mandatory from 2027 for the world's largest emitters.
Airlines have supported a global agreement in favor of a potentially more costly patchwork of national and regional deals.
An ICAO spokesman could not provide an immediate comment.