The United Nations’ body that oversees civil aviation has reached an important milestone in international efforts to craft effective and equitable solutions to climate change from this fast-growing sector. And this success last week in Montreal should send a hopeful signal to other UN organizations as they grapple with the challenges of limiting greenhouse gas emissions.
At the 38th General Assembly of the International Civil Aviation Organization  (ICAO), governments endorsed a comprehensive set of actions aimed at achieving an aspirational mid-term goal of zero carbon emissions growth for the aviation industry beginning in 2020. The October 4 accord brings together a number of measures being developed by ICAO, including: a certification requirement for a global CO2 efficiency standard for aircraft; support for an updated, more efficient air traffic control regime; continued development of sustainable biofuels; and updating national action plans laying out country strategies to reduce emissions.
By far the most contentious issue involved the role of market-based measures in reducing emissions. After years of unproductive discussions within ICAO, the European Union set out rules last year to bring international aviation emissions within its own emissions trading regime. After a widespread backlash , the EU put its action temporarily on hold. These events put even more pressure on ICAO to come up with a timely and acceptable global solution.
The agreement reached October 4 states that ICAO “decides to develop a global market-based measure scheme for international aviation” to be considered at the next General Assembly in 2016 and implemented in 2020. As a result, aviation would become the only major industry sector on a path toward a global market-based mechanism agreement to limit future greenhouse gas emissions.
While the ICAO agreement is a major milestone toward a global solution to curb aviation emissions, much more remains to be done. Several large developing nations (including India and China) placed “reservations” on the agreement signaling continued concerns about the ability of ICAO to find an acceptable path forward in 2016.
Addressing aviation emissions is significant. While emissions from planes make up only about 3 percent of total carbon dioxide emissions now, if left unaddressed, they could rise to between 4 and 6 times current levels by 2050.
The ICAO agreement effectively moves nations down a path toward a global solution involving both developed countries and fast-growing developing countries. Let’s hope this is a model for action at the upcoming meeting this month of the Montreal Protocol where countries have an important opportunity to further advance efforts to reduce climate change through actions to limit hydrofluorocarbons  (HFCs), another small but fast-growing segment of greenhouse gas emissions.