Five Nobel prize winners are among 26 US economists calling on Barack Obama to drop his government’s opposition to EU legislation charging airlines for their carbon emissions.

The US has been highly critical of the EU’s move to include airlines in its emissions trading scheme (ETS), claiming it is illegal under international treaties and backing a lawsuit challenging the plan that was dismissed by the European Court of Justice.

At the end of last year, secretary of state Hillary Clinton wrote to EU commissioners, warning “appropriate action” would be taken if Brussels did not halt or delay its plans.

And last month, the US was joined by about 25 other countries, including China, India and Russia, at a meeting in Moscow that concluded with an agreement on “counter-measures” designed to undermine the EU’s plan.

The EU agrees with the US and other critics that the best way to address the aviation industry’s emissions is to agree on global action through the International Civil Aviation Organisation (ICAO). However, the UN body, which meets in Montreal this week, has yet to come up with an official emissions plan despite a decade of negotiations, prompting the EU to take unilateral action.

In an open letter (PDF) published yesterday, economists from universities including Harvard, Stanford, Columbia, Princeton and Berkeley urged president Obama to endorse the EU policy as a first step towards a global agreement at ICAO.

“We implore you to support the European Union’s innovative efforts to place a price on carbon from aviation through the emissions trading system (EU ETS), or, at the very least, to stop actively opposing these efforts,” it reads.

It also warns the price of emitting CO2 from aircraft must reflect the social cost. If it does not, the world will continue to neglect investments in technology designed to reduce emissions.

Aviation currently accounts for about three per cent of global emissions, but this is expected to quadruple by 2050 as global travel increases.

“Today the US is leading a coalition of unwilling countries on a course of refusing to price this risk in the commercial aviation sector,” the letter continues. “Rather than opposing the EU, we urge your administration to support their efforts to price carbon in the context of the ICAO.”

The letter comes after seven airlines and two manufacturers wrote to the European Commission and EU leaders, calling on them to postpone their inclusion in the ETS and work towards diffusing a potential trade war with China over emissions trading.

The EU has consistently rejected all calls to axe the scheme, insisting that it will only exclude airlines from the US if comparable measures to curb emissions are agreed at a global level.

The letter also coincides with the US visit of British prime minister David Cameron, during which the issue of the EU’s aviation plan is likely to be discussed.