The Brookings Institution. January 23, 2012.
With limited progress in the U.N. climate change negotiations, the European Union has been looking at ways to further reduce global CO2 emissions by extending the scope of its cap-and-trade system, most recently through flights entering and leaving EU airspace. The EU Aviation Directive entered into force on January 1st, 2012, requiring all airlines to hold permits covering their CO2 emissions for flights operating in EU airspace. [Note: contains copyrighted material].