At a two-day meeting in Washington, D.C., this week, international stakeholders reaffirmed their unified opposition to the European Union emissions trading legislation on air carriers but showed limited enthusiasm for a global market measure that could replace the unilateral E.U. directive.

"We are among a large number of countries, probably most everybody outside of Europe that have opposed the application of Europe's emission trading system to foreign air carriers on both legal and policy grounds," said a senior U.S. administration official after the summit.

"But at the same time as we have opposed the application of the ETS in that manner, we have been strongly supportive and many countries strongly supportive of the objective of reducing emissions from aviation," the official said.

The meeting was designed to be an informal conversation among 16 countries and the United States, all of which are against the E.U. law but support progress at the multinational level in the International Civil Aviation Organization, or ICAO.

Support, however, was mostly limited to the existing 2010 ICAO Assembly resolution and did not advance the discussion on a global market measure -- such as cap and trade or an offsetting mechanism -- that could replace the E.U. system.

"It is my sense -- although we don't know for sure -- but it is my sense that it is going to be a substantial period of time of working on what might be a global measure," said the senior administration official.

The 2010 assembly did highlight ways to reduce aviation emissions, including the improvement of air traffic management systems through efforts such as the Federal Aviation Administration's NextGen program. It also supported the use of market-based measures in national or regional systems, but not on a universal scale.

ICAO is exploring the possibility of a global market solution to rival the E.U. Emissions Trading System, but the U.S. official said it's unclear whether an agreement will be reached by the next full assembly meeting in fall 2013. Under the E.U. law, all airlines taking off and landing in Europe must start paying into the trading system next April.

What will be the price of noncompliance?

Meanwhile, the Senate Commerce Committee passed legislation this week that would give the Transportation secretary the authority to prohibit U.S. airlines from participating in the system. Sen. John Thune (R-S.D.) said he hoped it would see a vote on the Senate floor this week (ClimateWire, Aug. 1).

China and India have already barred their airlines from acknowledging the E.U. law. Chinese and Indian airlines were the only ones not to register their 2011 emissions with E.U. member states earlier this year (ClimateWire, May 16).

But many in the United States fear that noncompliance from American airlines would trigger a chain of retaliatory actions that could lead to mounting fines, impounded planes and damaged relations between close allies at a time of fiscal turbulence.

After the Senate committee cleared the Thune bill, E.U. Parliament Environment Committee Chairman Matthias Groote called the action "disrespectful and counterproductive."

"The E.U. decision in 2008 to include aviation in its emissions trading reflects the fact that we all stand to gain by minimizing the effects of climate change," he said in a statement. "It followed a simple reality: Many years of international talks were failing to get a result, while global aviation emissions doubled between 1990 and 2006."

Global aviation emissions account for only 2 to 3 percent of all greenhouse gas pollution but are on track to quadruple from 2005 levels by 2050.

But airlines, even in countries opposed to the E.U. ETS, have been taking measures to reduce their emissions with efforts such as testing of biofuels and purchasing more fuel-efficient aircraft. Countries are against having the ETS imposed from the outside, not to reducing the aviation sector's carbon footprint, said the U.S. official.

Whether the United States would lead opponents in a challenge under Article 84 of the Chicago Convention -- a rule that allows ICAO members to file a serious complaint for the violation of state sovereignty -- was also discussed at this week's meeting of international representatives. According to the administration official, "Article 84 is not off the table, but we don't have any immediate plans to do that, but it is always an option."