International negotiations on aviation CO2 emissions have concluded with a deal being agreed.

Representatives at the International Civil Aviation Organisation (ICAO) in Montreal ended years of talks by agreeing targets to cut emissions from 2020.

From that date any increase in airline CO2 emissions will be offset by activities like tree planting.

UK aviation minister Lord Ahmad said: “This is an unprecedented deal, the first of its kind for any sector.

“International aviation is responsible for putting more carbon dioxide into the atmosphere every year than the whole of the UK, and yet until now, there has been no global consensus on how to address aviation emissions.

“For years, the UK has pushed to tackle emissions globally. Now, 191 countries have sent a clear message that aviation will play its part in combating climate change.”

With aviation accounting for an increasing proportion of the world’s carbon emissions the ICAO previously promised carbon neutral aviation growth by the 2020s.

This would have brought the sector in line with the Paris agreement on climate change limiting global warming to two degrees Celsius, or preferably 1.5 degrees.

Tim Alderslade of the British Air Transport Association welcomed the ICAO deal.

“It should not be forgotten that we are the only industry that has voluntarily agreed to such a commitment.

“As a sector we have really decoupled growth in aviation from growth in emissions.”

Airline association Iata hailed the agreement as “historic”. Iata director general Alexandre de Juniac said: “CORSIA is the first global scheme covering an entire industrial sector. 

“Even states that would normally not be required to participate have shown their commitment by signing up. We estimate Corsia will cover more than 80% of growth post-2020.”

However, Iata noted: “By itself, Corsia will not lead to a sustainable future for aviation. The industry will continue to drive its four-pillar strategy on climate change, comprising improvements in technology, operations and infrastructure.”

Members of the Airlines for Europe (A4E) group, which includes IAG, easyJet and Ryanair, also applauded the deal, saying: “This unprecedented agreement is a milestone in the history of international climate change policy.

“There is now an opportunity to have a fresh look at environmental regulation in the European context and to review existing measures addressing CO2 emissions from aviation.”

However, the Aviation Environment Federation described the deal as merely “a first step to address emissions from international aviation” and has having “mixed results”, while recognising it “as a hard-fought political compromise”.

The AEF said: “Countries sent a worrying signal by deleting key provisions for the aviation agreement that would align its ambitions with the Paris Agreement’s aim of limiting global temperature rise to well below 2 degrees.

Tim Johnson, AEF director and lead representative of The International Coalition for Sustainable Aviation (ICSA), said: “Viewed globally, this is a landmark deal that addresses a gap in the plan to deliver the Paris Agreement, namely how to tackle the soaring emissions from international aviation.

“But there are gaps in coverage and many issues still to be decided. We urge ICAO and states to view the goal of keeping net emissions at 2020 levels as the start of a process.

“This international effort falls well short of the effort required to bring UK aviation emissions in line with the Climate Change Act.”

The AEF said: “Aviation emissions are projected to consume approximately a quarter of the world’s remaining carbon budget by 2050, highlighting the urgency of reaching an agreement.

“The integrity of the agreement’s emission reductions depend on rules not yet in place.”

Environmental campaigners were also critical. Bill Hemmings of the green group T&E said: “Airline claims that flying will now be green are a myth.”