The European Union sees a "window of opportunity" for reaching a global deal on aviation carbon-emissions curbs by the start of next year, said Joao Vale de Almeida, EU ambassador to the United States.

The inclusion of flights to and from EU airports in the European emissions trading system as of this year triggered opposition from countries including the US, China and Russia, which said Europe should let the United Nations' International Civil Aviation Organization, or ICAO, decide on greenhouse-gas limits for the industry.

"We remain fully committed to an international deal," Vale de Almeida said at the European Policy Centre in Brussels on Monday. "Things have started again in the ICAO because there is the regulation in Europe, and we are happy about that."

The 27-nation EU, which wants to lead the global fight against climate change, decided in 2008 that aviation should become as of 2012 a part of its cap-and-trade plan. Airline carbon-dioxide discharges in the region doubled over two decades and international organizations failed to enact pollution curbs.

The UN aviation body is now considering four possible market mechanisms to tackle greenhouse-gas pollution, ICAO President Roberto Kobeh said earlier this month.

The organization's 190 members may make a final decision at a meeting in September or October next year, he said.

The US is now "fully engaged" in the process, according to Vale de Almeida. He also reiterated the EU won't back down on its carbon curbs for aviation before a global deal is in place.

"We cannot suspend legislation like that, as you well know," he said.

The EU can replace its emissions trading system with a global measure to cut pollution from the industry as long as the broader program is as ambitious as the European plan, the bloc's Climate Commissioner Connie Hedegaard said last month.

Airbus SAS Chief Executive Officer Tom Enders on Sunday called upon the EU to freeze the bloc's carbon limits on aviation for "a year or two" to win time and set global rules on the matter.

The company is at risk of having a "significant number" of planes not delivered into China amid protests by the country's carriers against the program, Enders said.

China's aviation regulator has signaled that it hasn't forbidden the nation's airlines from buying Airbus planes.

Airlines are encouraged to buy planes based on costs savings and increasing reliability and safety, Li Jiaxiang, director of the Civil Aviation Administration of China, said in an interview in Beijing on March 10.