Environmental NGO Opportunity Green has submitted a written statement to the International Court of Justice (ICJ), asking the court to confirm that States have legal obligations under international law to tackle climate impacts from international aviation and shipping (IAS) in accordance with the Paris Agreement’s 1.5°C temperature goal.

Aviation and shipping sectors contribute to nearly 5% of global greenhouse gas emissions. Emissions from international aviation and shipping (IAS) make up for more than half of that number. Yet, most States do not currently account for the emissions from IAS in their national climate pledges under the Paris Agreement, so-called nationally determined contributions (NDCs). This goes against the very purpose of the Paris Agreement, which calls for a global response to limit the global temperature increase to 1.5°C.

It is a misconception that States should rely solely on specialised United Nations agencies, the International Maritime Organization (IMO) and International Civil Aviation Organization (ICAO), to act on IAS emissions – and yet, this is what most States do in practice.

Not only do existing ICAO and IMO targets fall way short of driving decarbonisation of those sectors to meet the Paris temperature goal, but States also have standalone legal obligations to reduce greenhouse gas emissions from IAS. Opportunity Green’s submission to the ICJ argues that the efforts of the ICAO and IMO are additional to action under States’ individual NDCs. It is not enough for States to leave the decarbonisation of these sectors to these UN bodies.

To date, IAS have sailed under the radar of negotiations under the United Nations Framework Convention on Climate Change (UNFCCC), but the Court’s advisory opinion represents a unique and vital opportunity to change the direction of travel.

Isabela Keuschnigg, Legal Officer at Opportunity Green, notes: “When it comes to international aviation and shipping, we are talking about major polluters that contribute significantly to the climate crisis – and yet, they remain weakly regulated.

“With a new, stronger round of NDCs due in 2025, and critical discussions underway at the IMO on the measures needed to implement its revised GHG strategy, this is a watershed moment to put these sectors on a clearer course towards net zero. The science is clear in that we need rapid and deep transformations across all sectors and systems immediately. In the face of inadequate action taken to date, we urgently need clarification of States’ legal obligations to mitigate emissions from international aviation and shipping under the Paris Agreement. We’re urging the ICJ to confirm that international law obliges individual States to act decisively to address the substantive emissions from these sectors.”

Important climate negotiations wrapped up at the IMO headquarters in London early in 2024, with further talks planned for later in the year to discuss the “basket of measures” that will support delivery of the revised GHG Strategy for shipping. This submission to the ICJ will underline to States that their international legal obligations, particularly under the Paris Agreement but also the Law of the Sea, mean that they must confirm measures that set international shipping on a pathway to reduce emissions in line with 1.5°C.

Ms Keuschnigg adds: “For too long, the international aviation and shipping sectors have evaded any serious scrutiny of their decarbonisations efforts, and these emissions keep growing and growing. But the advisory opinions currently in front of the ICJ and the International Tribunal for the Law of the Sea are contributing to increased judicial oversight of these sectors at an international level, and offer a crucial opportunity for international courts to confirm that there are no excuses for insufficient climate action. IAS as much as every other sector must be held accountable and play their fair part in the efforts needed to reach a decarbonised global economy.”

This year will be key for States to ramp up their climate efforts. Not only must States revise their NDCs to account for all shipping and aviation emissions, they must act decisively to tackle the substantive climate impacts from these two sectors. Opportunity Green’s written statement to the ICJ makes clear that while this is necessary from a scientific point of view, it is also a matter of complying with international law.