The Growing Role of International Climate Litigation: Insights from the Commonwealth Round Table on Advisory Opinions

Yesterday, the Commonwealth Secretariat hosted a Round Table on Advisory Opinions on Climate Change at Marlborough House, bringing together leading experts to explore how international and regional courts are clarifying state obligations, strengthening accountability, and protecting vulnerable communities. ICwS Associate Research Fellow Maud Sarlieve was in attendance.

With the recent ITLOS ruling and advisory opinion (AO) proceedings currently before the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACtHR), international law is playing an unprecedented role in shaping climate governance. But what can AOs actually achieve? How might they influence future litigation, diplomacy, and policy?

Key insights from the discussion:

• Prof. Margaretha Wewerinke-Singh highlighted how Vanuatu’s ICJ AO campaign serves not just as a legal tool but as a diplomatic strategy, providing crucial interpretive guidance for Small Island Developing States (SIDS) facing disproportionate climate impacts.
• Harj Narulla examined the risks and opportunities of multiple AO proceedings—could divergent rulings lead to legal fragmentation or strategic forum shopping? He also explored potential guidance on reparations, including cessation, non-repetition, and compensation for climate harms.
• Maud Sarlieve, Fellow at the Institute of Commonwealth Studies (ICwS), explored the AO’s ripple effects beyond environmental law—into human rights, migration, trade, and corporate accountability. Could the ICJ AO reinforce due diligence as a binding legal principle, influencing national courts and regulatory frameworks worldwide?
• Aditi Shetye underscored the pivotal role of youth-led movements in mobilising global support for the AO, shaping diplomatic engagement, and pushing for stronger climate action through strategic litigation and advocacy.

As climate litigation accelerates across international, regional, and domestic courts, advisory opinions could provide a critical legal foundation for holding states—and corporations—accountable.