At the close of its 37th Assembly last Friday, the International Civil Aviation Organization (ICAO) agreed to what it characterized as the first global approach to reducing air transport's impact on climate change. Under the resolution, ICAO committed to achieving a 2-percent annual fuel efficiency improvement until 2050, as well as a global framework for the development and deployment of sustainable alternative aviation fuels and a world standard covering carbon dioxide limits for aircraft engines. The resolution also calls for the creation of a global market-based measures scheme. But with the ink barely dry on the document signed by the UN body's 190 member states, opinion remains divided as to whether the development weakens or strengthens the European Union's emissions trading scheme. EU transport commissioner Siim Kallas was quick to claim that the ICAO agreement effectively provides validation of Europe’s unilateral approach to cutting emissions through its ETS cap-and-trade system. The EU has always said that it will exempt non-European operators from its ETS if their own national governments have implemented a comparable system. However, the EU has made it clear that it will not defer ETS implementation while it waits to see if such alternatives ever materialize.