Why aviation’s carbon must be capped, and how to do it

Airplanes on a flooded runway at Don Muang International Airport on Nov 19, 2011 in Bangkok, Thailand. Image: 1000 Words / Shutterstock.com

Government negotiators met in Montreal last week to seek agreement on a global cap on carbon pollution from international aviation. Bilateral negotiations are continuing, and text of a draft resolution is expected to be considered at the triennial meeting of the UN’s International Civil Aviation Organization (ICAO) in early October.

In anticipation of these meetings, Carbon & Climate Law Review (CCLR), a broadly-read journal catering to climate insiders, just released a special issue on international aviation. Experts illustrate the need for and feasibility of a strong market-based measure. Here are some highlights from the special issue:

Aviation’s impact on climate is understated

Aviation’s total global warming impacts are more than double those estimated from its carbon dioxide (CO2) emissions, or equivalent to roughly 5% of total radiative forcing from CO2. Nitrogen oxide emissions and aviation’s impacts on clouds add significantly to the warming effect of carbon dioxide. Without new policies, aviation emissions could compromise the goal of the 2015 Paris Agreement to limit the increase in global temperatures to 1.5 – 2 degrees Celsius above pre-industrial levels.

Climate change increases risks to aviation safety, infrastructure, and operations

Aviation pollution causes harm to the climate, but a warming climate also creates challenges for aviation safety and operations.

According to industry experts, in high temperatures, planes can’t carry as much. Airports risk damage to runways from storm surge and rising sea levels. Passengers and crew may be exposed to more turbulence. New electronics, sensing, and communication technology may be needed to reduce the risk of exposure to severe weather.

The solution: a market-based measure

To contain aviation’s impacts on climate change, experts from industry, policy, and law call for a market-based measure to cap emissions from international flights.

A market-based measure can be established and enforced under existing law

Legal experts recommend that an MBM can be established as a set of “standard” under the existing Chicago Convention, the foundational treaty for international aviation. Compliance with existing standards is good but not perfect. The experts show how market entry conditions, domestic transportation statutes, and conditions imposed by aviation financial services and trade associations can be used to bolster compliance.

A market-based measure should provide broad coverage and deliver co-benefits

Expert contributors to the issue recommend that the coverage of the MBM be broad. They caution that exemptions from a market-based measure could distort the market and disproportionately benefit the wealthiest individuals in those countries.

Other contributors show that policies to reduce emissions from deforestation and forest degradation (REDD+) can help meet international aviation’s demand for emissions offsets, even after taking into account existing commitments and demand for offsets. Further, a “keep what you save” policy that allows air carriers to use their own fuel use reductions to reduce offsetting obligations could help resolve current debates over allocating offsetting obligations between air carriers.

This fall’s ICAO General Assembly is a critical moment for countries, and the aviation industry, to demonstrate leadership in providing safe international air travel while minimizing risks to the climate.

If countries don’t agree to the market-based measure in October, the world may have to wait until ICAO’s next General Assembly in 2019. With rapid growth of aviation pollution, that’s a delayed take-off that none of us can afford.

Click “read more” to see key takeaways from each article of the special issue of CCLR. The journal’s publisher, Lexxion, has made the special issue free to access through October 7, 2016.


Key points from each article in CCLR’s special issue on “A Market Based Measure for International Aviation: Need, Design, and Legal Form”:

Aviation and Climate Change: A Scientific Perspective, David W. Fahey and David S. Lee

  • Aviation’s total global warming impacts are more than double those from its CO2 emissions, or equivalent to 5% of total radiative forcing from carbon dioxide.
  • Nitrogen oxide emissions and aviation’s impacts on clouds add significantly to the warming effect of carbon dioxide from aviation.
  • Impacts of CO2 emissions are best understood, impacts of contrails and cirrus cloud formation more uncertain.
  • Climate effects of non-CO2 emissions from aviation are not uniform throughout the atmosphere.
  • Use of alternative fuels results in significantly lower emissions of small soot particles which control contrail formation and could potentially reduce not just CO2 contributions, but cirrus contributions.
  • Balancing short term impacts of aviation on cirrus clouds, which have regional effects, and the long term impacts of CO2, which has a global effect, poses challenging policy issues.


Climate Change Impacts Upon the Commercial Air Transport Industry: An Overview, Terrence R. Thompson

  • Every sub-sector of the aviation industry, including airports, air carriers, air navigation service providers, and aircraft and engine manufacturers, faces risks from climate change.
  • Airports may face heat damage to runways, decreased operational efficiency, increased delays, and intermittent or permanent closures.
  • Aircraft may experience decreased climb performance in high heat, increased icing conditions, and impacts on design requirements for airframes, engines, and avionics and weather conditions change.
  • Passenger and cargo demand may shift following changes in weather patterns.
  • Passengers and crew may face exposure to increased turbulence and increased delays.
  • As air carriers and airports respond to these changes, local communities may experience changes in noise, air, and water quality impacts.


Maintaining Aviation Safety: Regulatory Responses to Intensifying Weather Events, Herbert Pümpel

  • Aviation regulators will need new safety procedures to manage risks posed by climate change.
  • Aviation’s traditional risk management measures may not work in an environment of increased, and uncertain, intense weather events.
  • New meteorological, sensing and communication technologies are needed to minimize risks that aircraft encounter severe weather.
  • Aircraft designers need input on the “worst case” scenarios that aircraft may face in an unstable climate.
  • Air carriers and regulators may need new approaches for informing consumers, and crew, about aviation safety risks.


Aviation and Climate: An ATAG Perspective, Michael Gill

  • Aviation is a global industry that needs a global solution to reduce its impact on climate change.
  • Technology, operational efficiency, new infrastructure, and a global cap are all needed.
  • A global offsetting system can provide significant social benefits and enable the aviation sector to continue to grow.


ICAO’s Market Based Mechanism: Keep it Simple, ParthVaishnav

  • Airlines’ offsetting obligations should be proportional to their total emissions.
  • Exemptions from a market based measure distort the market and disproportionately benefit the wealthiest individuals in those countries.
  • Action on international emissions needs to be matched by regulations to limit domestic aviation emissions.


Bridging the Allocation Gap: A New Proposal, Annie Petsonk and Pedro Piris-Cabezas

  • Air carriers can be encouraged to reduce their fuel use if a market-based measure includes a provision allowing carriers to credit, against their offsetting obligations, carbon emissions below a set baseline.
  • Determining whether flights to a particular State should be covered under an MBM is a separate question from how to allocate, between different air carriers, offsetting obligations for covered routes.


REDD+ in ICAO: Ready for Takeoff , Rafael Grillo Avila, Michael Wolosin, Alec Roth, Ruben Lubowski, Pedro Piris-Cabezas, Garrett Russo

  • Emissions units generated under the REDD+ legal framework can satisfy aviation’s demand for offsets on a short, medium, and long-term basis, even after reserving credits to meet domestic nationally determined contribution (NDC) obligations.
  • REDD+ is a well-developed framework for forestry-based offsets, and many programs already exist to implement it.
  • Assessment of REDD+ credits under existing and anticipated programs shows an ample supply of offsets after reserves are established for buffers, existing commitments, and nationally determined contributions, even under high estimates for aviation’s offsetting demand.
  • Supplies are even larger if jurisdictional REDD+ systems are implemented.
  • An MBM for aviation can help generate demand for REDD+ offsets.


Designing the Legal Form of a Global Market Based Measure, Alejandro Piera

  • A “standard” issued under the Chicago Convention is the most compelling, if imperfect, legal option for creating an aviation MBM.
  • Establishing an MBM via a treaty would be slow and unlikely to be adopted broadly enough to take effect.
  • Assembly resolutions are non-binding and thus limited as a legal form.
  • An MBM could be established as an ICAO standard, but not all states comply with standards when there is an economic incentive not to do so.
  • Transparency measures, reporting non-compliance to the ICAO assembly, and market access conditions could all be used to increase compliance with an MBM.


Legal Implementation of a Global Market Based Measure for Aviation, Pamela Campos

  • Distributed, overlapping compliance measures are needed to ensure an MBM’s effectiveness.
  • Strong implementing institutions, public access to data, and well-designed financial penalties are required to achieve broad compliance with an MBM.
  • The Chicago Convention and many bilateral air services agreements enable States to require demonstration of compliance with an MBM as a condition of market entry.
  • Aviation financial services firms and trade associations can bolster compliance by requiring clients and members to demonstrate they are complying with an MBM.


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