International airlines that fly into Europe have lost a bid to block a law that charges them for their carbon pollution, a measure that will soon boost the cost of traveling to and within the continent.

The European Court of Justice ruled Wednesday that the law including airlines in the European Union's emissions trading scheme is valid.

It is set to take effect New Year's Day and is part of the EU's environmental plan to limit the release of pollution-causing carbon dioxide into the atmosphere. Corporate interests, including airlines, can buy carbon credits to cover the cost of their emissions, but the goal of the law is to encourage their investment in clean technologies to curb pollution.

The ruling could lead to a diplomatic dispute between the EU and some of its biggest trading partners. U.S. and Canadian airlines, supported by carriers in China, India and elsewhere, contested Europe's unilateral imposition of the carbon trading system, saying there should be a global agreement on how to limit carbon dioxide emissions from airliners.

The U.S. warned that it will attempt to counter the ruling, saying that it “strongly objects” to it.

EU officials have estimated that the rule will add $3 to $16 to cost of a one-way ticket to European destinations, depending on the length of a flight.