The International Civil Aviation Organization (ICAO) Council has agreed to a compromise solution on the introduction of global market based measures (MBMs) to tackle aviation emissions.

The council accepted the principle of regional emissions trading schemes and agreed to have a single global MBM for aviation to be implemented from 2020. The principles for a global MBM should be adopted at ICAO’s assembly in 2016.

The Council adopted an article proposed by the EU that “recognizes that states or groups of states may choose, prior to the full implementation of a global MBM scheme, to implement MBMs that apply to flights to or from third countries which depart or arrive at airports in that state or group of states for the portion of those flights within the airspace of that state or group of states, and would fully cover all emissions from flights which both depart and arrive at airports in that state or group of states.”

With the ICAO Council’s agreement, the EU will implement an adapted ‘Stop the Clock’ exemption until 2020 that will impose ETS on parts of a flight using EU air space. Overflights will not be included, but for instance a flight from London to New York will be included in the scheme for the part using European air space.

The current Stop the Clock measure exempts flights between an EU airport and a non-EU airport and only intra-European flights, irrespective of the nationality of the carrier, have to take part in the EU ETS.

Yesterday’s debate was lengthy and difficult, but the draft working paper received the support of the majority of the 36 member states that make up the ICAO Council. Several countries, including Argentina, Brazil, Cuba, India, Saudi Arabia and the U.S. had strong reservations, but they did not block the agreement, insiders tell Aviation Week.

All 191 of ICAO’s member states vote on the Council’s draft working paper as the body’s next assembly, which is being held in Montreal Sept. 24-Oct. 4. The conclusion is weaker than the EU would have liked, but EU climate action commissioner Connie Hedegaard in a message on Twitter welcomed “progress within reach of a global MBM.” Hedegaard, however, noted that lot of work still needs to be done.

According to insiders, several points are still under negotiation, including provisions for developing countries.

The European Low Fares Airline Association (ELFAA), which in April vowed to fight the Stop the Clock in court, denounced the agreement, saying it imposes an unfair burden on intra-EU operators. According to ELFAA, the current Stop the Clock measure also discriminates by treating long-haul flights more favorably than short-haul flights.

Environmental groups also find cause to criticize the new deal, albeit, as Bill Hemmings of environmental group Transport & Environment notes, because it is an “appeasement on a grand scale.”

In contrast, Peter Liese, a senior member of the European Parliament’s powerful environment committee, seemed to accept the ICAO deal favorably, although he cautioned that the agreement needs to be scrutinized and accepted by the Parliament.