If you fly, aviation emissions are likely the largest part of your personal carbon footprint. Absent policy change, aviation’s emissions are slated to triple in the coming decades, making it one of the fastest-growing sources of carbon pollution worldwide.

To achieve the Paris Agreement goals of holding warming to well below 2 degrees Celsius and pursuing efforts to limit warming to 1.5 degrees Celsius, we need to address emissions from all sectors. This includes international aviation and international shipping, which most countries do not include in their Nationally Determined Contributions (NDCs) under the Paris Agreement. Back in 1997 when the Parties to the Climate Treaty couldn’t agree on how to allocate these international emissions, they asked the International Civil Aviation Organization (ICAO), the UN body that sets standards for international flights, and the International Maritime Organization, for ships, to address these emissions. How are their strategies stacking up?

In a forthcoming post, we’ll look at what’s happened lately in IMO. Here’s an update on ICAO. In 2018, ICAO adopted a set of Standards and Recommended Practices (SARPs) to implement the Carbon Offsetting and Reduction Scheme for International Aviation, or CORSIA. As an annex to the Chicago Convention on International Civil Aviation, the SARPs bring into effect an agreement reached in ICAO in 2016 to cap the net carbon dioxide emissions from international flights at 2020 levels through 2035. If implemented with integrity, CORSIA could prevent up to 2.5 billion tons of carbon dioxide emissions. That’s 10 times what U.S. households emit each year. It could do even more if CORSIA’s targets are extended and tightened.

To comply with CORSIA, all international airlines must monitor, report and verify their CO2 emissions. Effective January 1, 2021, airlines flying between participating countries will need to limit the emissions of those flights to the average of their 2019-2020 levels. To meet these emissions limits, airlines can reduce their direct emissions, or purchase and cancel carbon offset credits. Airlines can reduce the amount of offset credits they need by using sustainable, CORSIA-eligible alternative fuels that emit significantly less CO2 than conventional fuels when evaluated on a lifecycle basis.

In March 2019, ICAO took another step forward, agreeing on broad criteria that carbon offset programs will have to meet in order to be eligible to sell emissions units for use in CORSIA. The adoption of these criteria has sparked a sharp uptick in interest in carbon markets.

Countries are moving forward with implementing CORSIA

To date, 80 ICAO Member States have signaled their intent to participate in the pilot and first phases of CORSIA, from 2021-2026, when their participation is voluntary.

The three biggest players in the international aviation arena – China, the United States, and the European Union – have instructed their airlines to start monitoring, reporting, and verifying the CO2 emissions of their international flights, as required under CORSIA. China issued instructions to its air operators in late 2018.* The US followed in February 2019 with a program that, to date, has the participation of airline operators representing more than 97% of U.S. operators’ covered international emissions, including corporate fleets, freight carriers and passenger airlines.

And in March 2019, the EU adopted a Delegated Act revising its legislation to implement the ICAO monitoring, reporting, and verification requirements. The United Kingdom’s proposed Aviation 2050 plan, which is open to feedback from stakeholders through June 20, 2019, lays out policy proposals for a long term strategy for aviation, including environmental impacts.

CORSIA Technical Advisory Board

Who will determine whether offset programs meet ICAO’s emissions units criteria and are therefore eligible for use in CORSIA? ICAO recently released the names of members of a Technical Advisory Board (TAB) tasked with reviewing applications by carbon offset programs and making recommendations to ICAO’s Governing Council, which will decide program eligibility.

The TAB is expected to start work in May 2019, first adopting and publishing its operational procedures and terms of reference, and announcing a call for applications by carbon offset programs. A similar board is expected to be established to review aviation alternative fuels against sustainability criteria that are under development in ICAO.

Update July 2019: In June 2019, ICAO opened a call for applications for offset programs that wish to apply for CORSIA eligibility. While the application period is now closed, the ICAO TAB timeline anticipates opening a second round of applications in March 2020. Applicants need to complete the application form and the very important Appendix A and Appendix B.

The stakes are high – for airlines and for the planet

Aviation’s climate pollution is under a growing spotlight as activists around the world highlight the need for action to control it. CORSIA marks the first time that an entire global industry sector will operate under a mandatory carbon constraint. Done well, CORSIA could drive billions of investment dollars into low-carbon fuels and technologies, and spur competition to grind down their costs. CORSIA could also catalyze urgently-needed finance for reducing emissions from deforestation and degradation, making forests worth more alive than dead.

But to realize that potential, CORSIA’s TAB and fuels board, and ICAO’s Governing Council, will need to work rigorously, transparently and fairly. It is essential that ICAO publicly announce the application periods and processes for offset and fuel programs to be considered, afford ample opportunity for public review and comment on submitted applications, ensure that public comments are carefully considered, publish draft recommendations on eligibility well in advance of final decisions, and immediately yank the CORSIA eligibility of offsets and programs which are later found not to meet CORSIA standards.

ICAO must ensure that the eligibility criteria are faithfully applied, including the criterion which says that emissions reductions should not be counted twice – once by the host country and again by an airline in CORSIA. More than 50 companies with an employment footprint of a billion people in 100 countries have declared their support for sound carbon accounting, including in CORSIA, and their opposition to double counting. They, and we, see that double counting offset credits could undo CORSIA’s climate benefits.

Transparency will be crucial

The CORSIA institutions must operate with transparency to win the confidence of airlines and the public. Secrecy could invite backroom deals to bless subpar carbon credits and dubious fuels that don’t deliver any climate benefit and could make carbon pollution worse.

The credibility of international aviation’s climate efforts stands or falls on the integrity of CORSIA. We’ll be watching.

*Although China has not yet clearly stated that it plans to participate in CORSIA’s pilot phase, China has been actively monitoring its aviation emissions and participating in CORSIA-related technical discussions. An analysis by Shanghai and Guangdong about the possibility of incorporating aviation into their carbon trading pilots adds to the experience base for China’s future participation in CORSIA.