Emissions from international aviation are specifically excluded from the targets agreed under the Kyoto Protocol. Instead, the Protocol invites developed countries to pursue the limitation or reduction of emissions through the International Civil Aviation Organization. ICAO's environmental committee continues to consider the potential for using market-based measures such as trading and charging, but this work is unlikely to lead to global action. It is currently developing guidance for states who wish to include aviation in an emissions trading scheme (ETS) to meet their Kyoto commitments, and for airlines who wish to participate voluntarily in a trading scheme.