A Singapore Airlines Airbus A380 leaves contrails over the sky above Adelaide

MONTREAL (Reuters) – A U.N. agency agreed on Tuesday to change a landmark aviation emissions scheme, in a boost for airlines that said they could face billions of dollars in costs under the current deal when air travel recovers from the coronavirus pandemic.

The International Civil Aviation Organization’s (ICAO) governing council agreed to change the baseline year used for calculating emissions under the global CORSIA deal to 2019, the agency said in a statement.

Airlines, hit with a European-led backlash over pollution from flights, have pledged to spend billions of dollars under CORSIA to cap their emissions at 2020 levels through the purchase of carbon offsets.

Under CORSIA, which starts in 2021, airlines would buy carbon offset credits to cover any emissions from international flights above the current baseline of average emissions in 2019 and 2020.

But because emissions from international flights this year are set to drop significantly due to the sharp reduction in air travel as a result of pandemic, IATA asked that the baseline be changed exclusively to 2019, before the pandemic hit aviation.

ICAO said it would have created an “inappropriate economic burden to aeroplane operators, due to the need to offset more emissions although they are flying less and generating less emissions.”

Environmentalists opposed efforts to change the baseline to 2019, arguing it would allow airlines to pollute freely for years.

The European Union’s 27 member states backed IATA’s request, while two sources said the United States also supported the changes. China, Russia and India had argued they wanted more time to study the changes, the sources said.

CORSIA was launched following approval from most of ICAO’s member countries at the agency’s assembly in 2016.

(Reporting by Allison Lampert; Editing by Chris Reese and Leslie Adler)