Washington expressed concerns on Wednesday about European Union plans to demand carbon emissions permits for all flights as the two sides sought to end a standoff about fighting climate change, according to Reuters. "We are exchanging positions," Carlos Mestre, a European Commission official at talks on aviation in Oslo between the European Union and the United States, said during a break in the meeting. Delegation sources said Washington raised concerns about the legality of EU plans to widen penalties for carbon emissions to aviation from Jan. 1, 2012, as part of measures to slow global warming. Several U.S. airlines have gone further and are challenging the measure in European courts. Earlier this month, European Commission President Jose Manuel Barroso said the EU would not back down in imposing the new measures. . Mestre told Reuters the EU explained its plans to the U.S. delegation in the Oslo talks. The two sides were discussing whether the United States could impose "equivalent measures" to curb emissions that would allow exemptions from the EU rules. Washington has no plans to match the EU move from Jan. 1, 2012, when the EU will require all airlines flying to Europe to be included in the Emissions Trading Scheme (ETS), a system that forces polluters to buy permits for each tonne of carbon dioxide they emit above a certain cap. The U.S. Congress has called the EU plan "inconsistent" with the 1944 Convention on International Civil Aviation. So far, China has led opposition to the plan, saying it will cost Chinese airlines 800 million yuan ($123 million) in the first year and more than triple that by 2020. Several environmental organisations have urged the United States not to try to kill off the EU rules. -- SPA