“Can the ICJ’s new climate ruling save the planet?

In this episode of L’entretien IDN, an interview series from Initiatives pour le Désarmement Nucléaire our ED Kate Mackintosh, Professor from Practice a will answer the question: "Can the ICJ's new climate ruling save the planet?"

On 23 July 2025, the International Court of Justice (ICJ) issued a landmark advisory opinion clarifying what states are legally obliged to do about climate change—and what happens if they don’t. In this lecture and conversation, Professor Kate McIntosh (UCLA Law Promise Institute, Europe) explains what the ruling says, why it’s historic, and how it can be used—from courtrooms to climate negotiations.

Key points:

• What the ICJ actually decided. Climate change is recognized as an “urgent and existential threat.” States have binding obligations under treaties and customary international law to prevent significant climate harm and to cooperate.

• Ambition is not optional. National emissions targets must reflect the highest possible ambition, grow over time, and be capable of keeping warming to 1.5°C.

• Accountability has teeth. Subsidies for fossil fuels, inadequate targets, or new exploration licenses may amount to internationally wrongful acts with potential reparations.

• A right affirmed. The Court recognizes an autonomous right to a clean, healthy, and sustainable environment.

• How we got here. From a student-led campaign in the Pacific, to Vanuatu’s leadership, to a UN General Assembly request adopted by consensus, and oral hearings where 100+ states and 11 international organizations (including the WHO and OPEC) weighed in.

• What’s next. How this opinion can shape COP negotiations, domestic lawsuits, state-to-state actions, and corporate accountability, plus where the limits of law end and human will must begin.