After nearly 15 years of international talks to regulate airlines’ carbon dioxide emissions there is still no agreement on how to do so.

Which is why the European Union has taken it upon itself to unilaterally curb emissions by requiring all airlines operating out of EU airports in its 27 member states to financially offset their emissions starting Jan. 1. What that means is that airlines will have a cap on their annual carbon emissions and they would then be required to surrender one allowance for every ton of CO2 emitted on a flight to or from the EU. If an airline exceeded its number of allowances, it would be charged a substantial fine by being forced to buy more allowances.

Can you hear the uproar already?

Upon hearing of the EU’s plan, the U.S., China, India, and Russia, protested and even threatened to boycott what is being called the EU’s Emissions Trading Scheme (ETS). China is calling it an all-out trade war.

U.S. airlines are challenging the EU’s efforts, saying it violates U.S. sovereignty.

Last month the U.S.-based Air Line Pilots Association International told Congress it was opposed to the scheme and that it was unnecessary, given the significant reductions in emissions seen throughout the industry, the cost that would be placed on U.S. airlines to reduce emissions, and questions about the legality of it.

“The aviation industry takes seriously its environmental responsibility, and we have aggressively led efforts to cut carbon emissions by developing more fuel-efficient engines, using lighter-weight materials, creating biofuels, and capitalizing on satellite technology to route flights more directly and use less fuel,” said Capt. Lee Moak, ALPA’s president, following his testimony before the U.S. House Aviation Subcommittee’s hearing. The pilots association believes that it will cost billions of dollars just in the next couple of years for U.S. airlines to comply with the EU’s mandate, with no guarantee that the money will help reduce greenhouse gas emissions.

Moak pointed out that the U.S. airline industry is already significantly overtaxed, currently totaling more than $17 billion. He said a $300 domestic airline ticket currently includes $63 in taxes, or 20 percent of the total ticket price. “By piling on a foreign tax that will drive up ticket prices to the benefit of other countries, the EU Emissions Trading Scheme threatens the economic health of the U.S. airlines, risking U.S. jobs at a time when every job counts,” Moak said.

Of all the arguments against the EU’s plan, the question of where the money will go once it’s in EU coffers, and how it will be spent, is the most justified. Critics say there is no requirement that the profits from this charge be spent on global warming, or innovating new technologies, or reducing carbon emissions.

Yet supporters of the EU’s plan say emissions reductions have been regulated in other industries so why not airlines, one of the biggest culprits of carbon emissions? Aviation accounts for about 2 percent of global carbon dioxide emissions, which will only rise as 800 million more passengers hit the friendly skies by 2014 alone. The EU hopes to slash these emissions by 3 percent in 2012.