Punitive measures are already being taken against European airlines by countries disgruntled with the EU's Emissions Trading System (ETS), according to the Association of European Airlines (AEA).
Speaking to Flightglobal, acting AEA secretary general Athar Husain Khan says a number of airlines have complained to the association about problems they believe amount to retaliation for the scheme.
"We've moved from this idea of a potential threat and a risk of retaliation into a situation where we feel and see that there are a couple of airlines who are finding difficulties in getting overfly permits from Russia over Siberia," he notes.
"We see that there is increasing harassment of airlines," Khan continues. "Crew visas are now required for operations and flights where they were not required before." He notes that when airlines complain to Russian civil aviation authorities about these issues, some have been told it is happening because of the ETS.
Khan says Russia's politicians have made it clear during bilateral talks with European member states that "they will use any means at their disposal to at least get even with the EU" over ETS.
While Russia has so far been the leading protagonist in creating practical difficulties for airlines over ETS, Khan says he is concerned that other countries threatening action against European airlines will make good on their word.
"I do believe we're getting past sabre rattling. It's a really grave concern at the moment. I believe other countries will really go through with what they're threatening. Our airlines are experiencing very clear indications that this is not something that is going to go away," he warns.
AEA is opposed to the EU's ETS scheme, arguing that efforts to combat global greenhouse gas emissions should to be dealt through international cooperation, rather than being dictated by Europe. "This ... problem has to be solved at a global level and in our view ICAO is the perfect body to do that," he says.
While Khan is confident ICAO can deliver the necessary global solution, he is concerned at its lack of progress. "What I'm hearing now from Montreal is that they not will be able to agree on any kind of option over market-based measures before the end of the year, and that's being positive. You might be looking at the spring of 2013. We believe that's too late," he says.
Calling for immediate action, Khan says: "For an industry that's caught in the crossfire of this international battle, we need a solution as quickly as possible."