Addressing the glaring gap in climate plans: international aviation and shipping emissions

13 Feb

With the original deadline exceeded, countries have been granted an additional seven months to submit their climate plans under the Paris Agreement. We set out key takeaways from the recent webinar we hosted with Cornerstones Barristers where the panel of experts discussed a glaring gap in current Nationally Determined Contributions (NDCs): international aviation and shipping emissions.

Estelle Dehon KC of Cornerstone Barristers chaired an illuminating discussion with Payam Akhavan (legal representative of the Commission of Small Island States), Chris Lyle (aviation expert with over five decades of international policy experience), Damien Meadows (advisor at the European Commission) and Aoife O’Leary (CEO and Founder of Opportunity Green). The panellists explored the impasse which has resulted in decades-long accountability issues and delayed mitigation efforts in international aviation and shipping (IAS): the almost universal absence of IAS emissions from NDCs under the Paris Agreement.

Since the United Nations Framework Convention on Climate Change’s (UNFCCC) adoption, IAS emissions have been largely ignored from states’ efforts to tackle the climate crisis, allowing growth inconsistent with the Paris Agreement. Current policies put global shipping on a 2 – 3°C warming pathway by 2050 while international aviation aligns with 4°C+. 

The panel of experts emphasised the lack of ambition in both sectors and discussed governance gaps, shortcomings of UN agencies, and the role of legal frameworks and state action to bridge these gaps. This underscores the necessity, and legal obligation, to include these emissions in NDCs and reduce them in line with a 1.5°C pathway.

Webinar key takeaways

1. It is a ‘pervasive myth’ that international aviation and shipping emissions are not covered by the Paris Agreement

Damien Meadows described a ‘pervasive myth’ that IAS emissions are outside the Paris Agreement’s scope, with their regulation left to the International Maritime Organization (IMO) and the International Civil Aviation Organization (ICAO). Consequently, most states omit these emissions from their accounting obligations under the Paris Agreement, creating a reporting gap. The United Nations Environment Programme (UNEP) reports that around 71% of the CO2 emissions from shipping and 65% from aviation are international and are not typically included in national totals.

The panel traced the origins of this ‘myth’ back to the first attempts to operationalise the UNFCCC in 1997. Negotiators of the Kyoto Protocol failed to reach consensus on including emissions IAS in state’s targets and so concluded that further work should take place alongside pursuing reduction measures through the ICAO and IMO (Article 2(2), Kyoto Protocol). Yet the Paris Agreement supersedes this and does not repeat that position; in fact, it does not treat any specific sector separately and the temperature goal is global. Developed states, in particular, should undertake ‘economy-wide’ absolute emission reduction targets. It’s therefore a misconception of the Paris Agreement’s legal requirements that these sectors shouldn’t be addressed by states.

2. ICAO and IMO action is insufficient for states to discharge their legal obligations

Still, in theory states could work through the ICAO and IMO to meet their international climate obligations. But to the extent the rules adopted under them remain unaligned with 1.5°C, states need to take further domestic and/or regional action to be confident that they have met their legal obligations.

While both agencies have separately adopted goals pertaining to climate change mitigation strategies, the implementation and governance of these goals vary. The discussion highlighted the disparity between these goals and the Paris Agreement: the IMO failed to align with the temperature target through its 2023 revised strategy and the ICAO has adopted a long-term aspirational goal (LTAG) to decarbonise international aviation by 2050, but has not as yet set out any pathway to achieve such a goal.

Yet the IMO has shown promising signs. As noted by our CEO Aoife O’Leary, Small Island States have played a critical role in moving the needle in recent years. In 2025, the IMO must agree on a ‘basket of measures’ to govern GHG emission reductions. Thanks to the steady increase of voices from climate vulnerable countries, an ambitious fuel standard and pricing mechanism are currently tabled at negotiations.

ICAO, however, lags further behind and Chris Lyle pointed to many of its shortcomings, mostly imposed by its own legal governance. ICAO’s primary climate mitigation initiative, the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), relies on states to adopt national legislation and is based on out of sector emissions reductions. Additionally, it does not capture the non-CO2 effects of aviation, a problem which has been known about for 25 years. The way in which ICAO is governed also intrinsically allows for less ambition than at the IMO. And as Lyle pointed out, ICAO ‘has no regulatory power’.

3. States are obliged to account for and regulate IAS under international law

The discussion moved to the clearest legal obligations that apply to IAS. These lie in the UNFCCC as operationalised by the Paris Agreement, and the Law of the Sea, as recently clarified in the advisory opinion on climate change and the ocean of the International Tribunal for the Law of the Sea (ITLOS), briefly considered below.

The UNFCCC has a global target to stabilise GHG concentrations that should be “comprehensive and comprise all economic sectors”. Omitting two entire sectors, that together account for almost 6% of global carbon dioxide emissions, would then contradict the operational 1.5°C temperature goal of the Paris Agreement.

Under Paris, states are obliged to communicate GHG emission reduction plans through ‘nationally determined contributions’ (NDCs) every five years and these must “represent a progression” and reflect the “highest possible ambition”. Therefore, parties must provide clear information on IAS within their NDCs and their actions to mitigate these emissions.

Under the United Nations Convention on the Law of the Sea (UNCLOS), States must take “all necessary measures” to prevent, reduce and control marine pollution caused by GHG emissions from “any source”, including shipping and aviation (article 194(1)). ITLOS clarified it is not enough to simply participate in global efforts (capturing the IMO, ICAO and Paris Agreement) to discharge this obligation (paragraph 202) – states need to take all necessary measures, including individual actions.

Both UNCLOS and the Paris Agreement therefore impose obligations for states to take domestic and/or regional action to reduce emissions for IAS.

4. There are some – limited – signs of progress

Whilst most NDCs omit IAS emissions, a few countries/regions are taking steps to implement IAS into climate policy and legislation:

At the regional level, the European Union (EU) NDC partially includes international aviation and maritime emissions.

At the domestic level, Switzerland and the UK have included emissions from international shipping and aviation in their climate targets (albeit not in NDCs). Aotearoa New Zealand’s Climate Change Commission has recently issued advice for the government to amend its 2050 climate target to include both sectors.

Although unilateral and regional action marks an important regulatory step to reduce IAS emissions, uptake is very low. State-level action is not just important for the individual state, but as Meadows noted, it can help spur greater action at ICAO and IMO, too.

A great deal more action is needed in both sectors. As O’Leary put it, international aviation and shipping have ‘been a footnote for too long’.

5. The advisory opinions provide a critical opportunity to advance IAS action

The panel noted that courts are increasingly turning their attention towards obligations of states regarding climate change, and perceived ambiguities over control of IAS are swiftly becoming demystified by legal interpretations from the world’s top courts, such as the ITLOS advisory opinion mentioned above.

The ITLOS advisory opinion will likely inform the ongoing International Court of Justice (ICJ) climate proceedings, given there is some overlap in the matters being considered.

Payam Akhavan, who represented COSIS at the ITLOS advisory opinion, observed that submitting inadequate NDCs has been common practice, but stronger commitments are needed. He noted that it is critical that the ICJ follows ITLOS and confirms that merely meeting the procedural requirements of the Paris Agreement does not discharge state’s climate obligations under international law.

Small Island States have demonstrated global leadership in the world’s courts and at the IMO, and could yet do the same at ICAO. The panellists thought this represented a real opportunity, especially with the ICAO Assembly scheduled for later this year - but this burden should not be relieved by climate vulnerable countries. The upcoming ICJ advisory opinion could be pivotal, where all states’ obligations to act are unequivocally laid out.

IAS emissions can no longer be overlooked in NDCs

The potential for emissions reductions if states take responsibility for their share of international aviation and shipping is vast. Presently, these soaring emissions reflect a glaring gap in global climate accountability. By embedding international aviation and shipping within the headline target NDCs, states uphold international legal obligations and are compelled to strengthen climate action on them through effective regulation.

This webinar underscored the importance of decisive governance and coordinated global efforts to ensure these sectors do not go on ignored. States now have until September to show true ambition and account for these in the next generation of NDCs, to meet global climate targets.

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