By Allison Lampert and Tim Hepher

MONTREAL/PARIS (Reuters) -A United Nations body has begun global talks to hammer out a consensus on reducing airline emissions in the face of lingering discord over climate change and the impact of war in Ukraine.

The 193-nation International Civil Aviation Organization’s (ICAO) assembly, held every three years, is the first since COVID-19 put pressure on policymakers to speed up reforms.

It is also the first since Russia’s invasion of Ukraine soured international dialogue on a range of issues and set off a political storm over the alleged seizure of foreign jets.

Russia, which faces sanctions and a ban on the use of its airspace by Western airlines, urged the assembly to “stop the destructive actions of individual states,” saying the carbon cost of skirting Russia rendered climate efforts “pointless”.

The West says Russia has illegally confiscated hundreds of foreign jets, a charge Moscow denies. Both sides are expected to air their positions during the gathering from Tuesday in ICAO’s Montreal headquarters, once used as a Cold War back-channel.

A top ICAO official called for unity on long-term issues dominating the 11-day talks.

“I am very confident that member states … will come with an open mind to find a common understanding and present a way forward towards aviation and sustainability which is a central theme in this assembly,” Secretary General Juan Carlos Salazar told Reuters.

Airlines last year adopted a goal of net-zero emissions by 2050 in a de facto dress-rehearsal that drew reservations from Chinese carriers, reflecting Beijing’s more cautious stance on multilateral action.

Now the baton passes to governments, with airlines and their suppliers pressing for unity around the same goal to avoid destabilizing aviation.

“Anything shy of that in this assembly will be viewed as a failure,” Willie Walsh, director-general of the International Air Transport Association of global airlines, warned on Tuesday.

INACTION ‘NOT AN OPTION’

Airbus also urged leaders to rally behind the goal. “The ICAO Assembly … is really pivotal,” Executive Vice-President for Corporate Affairs Julie Kitcher told investors.

Airlines produce 2-3% of total emissions but some 12% of transport emissions – a percentage likely to increase as other modes switch to alternatives like electricity faster than currently appears possible for anything but the shortest fights.

“We have to do something,” Emile Nguza Arao, director general of Kenya’s Civil Aviation Authority, told Reuters. “Sitting on our hands is not an option.”

An ICAO preparatory meeting in July laid the groundwork for a 2050 net-zero target, a move the industry called “encouraging” while warning of tough negotiations.

The U.N. says more than 130 countries have set or are considering a net-zero target by mid-century to bolster adherence to the Paris Agreement.

China and Russia, however, aim to be “carbon neutral” by 2060, while Indian Prime Minister Narendra Modi has spoken of a 2070 target.

In an ICAO paper, Beijing called for assistance to developing countries to temper “discriminatory” carbon goals.

To secure an aviation deal, diplomats are fine-tuning a text setting an “aspirational” net-zero 2050 target while embracing different circumstances, a person familiar with the talks said.

ICAO can’t impose rules but its decisions influence national policies. Officials hope a global target will boost supplies of new Sustainable Aviation Fuel and encourage private investment.

Even then, aviation is expected to remain in the cross-hairs of climate groups who see the exercise as a smokescreen.

“A long-term emissions reduction goal with no enforceability plan is dead on arrival,” said Jo Dardenne, aviation director at Brussels-based Transport & Environment.

“There are no consequences for those countries failing to meet it, which means that most countries won’t take it seriously.”

(Reporting By Allison Lampert in Montreal and Tim Hepher in Paris; editing by David Evans)