IUCN: States have a legal obligation to fight climate change

Between December 2 and December 13, 2024, almost 100 States and 12 international organizations participated in historic proceedings of the International Court of Justice (ICJ) in The Hague to provide their advisory opinion on the legal obligations of States to protect the climate and to determine whether noncompliance with these obligations could result in legal consequences.

Header photo: IUCN Director General Dr Grethel Aguilar addressing the ICJ (c) ICJ

IUCN also took part in these proceedings and addressed the Court on the last day. As a union, IUCN plays a unique role representing 1400 members (both States and civil society organizations) from over 160 countries. It also draws upon the extensive legal and scientific knowledge from its more than 17,000 experts in 170 countries, especially those of the IUCN World Commission on Environmental Law, adding significant weight to its arguments to the Court.

During the oral proceedings in The Hague, IUCN was represented by Director General Dr Grethel Aguilar Rojas; Prof. Christina Voigt; and Prof. Francesco Sindico, Co-chair of the Commission’s Climate Change Law Specialist Group.

‘This Advisory Opinion is pivotal in clarifying international law, shaping future climate action, and addressing the global climate crisis in a manner that is equitable, effective and enforceable,” said Dr Aguilar during her intervention.’(The Court’s) opinion matters to those that are most vulnerable to the impacts of climate change, be it States that are fighting to protect their peoples and territories, vulnerable communities, indigenous peoples, migrants, women, and children – and of course the natural world. Your opinion will send a powerful message to States and other actors responsible for greenhouse gas emissions, emphasizing the urgent need for deep, rapid, and sustained reductions aligned with 1.5°C pathways,’ she added.

States obligations to protect the climate system

According to Prof Voigt, Chair of the IUCN World Commission on Environmental Law, States’ obligations to address climate change come from independent and cumulative international legal sources, including the 2015 Paris Agreement, the UN Convention on the Law of the Sea, international human rights treaties, and customary international law.

Under the Paris Agreement, she told the Court, States have several obligations, including submitting and adhering to nationally determined contributions – individual country-level goals – to help meet the goal of holding warming to 1.5 degrees. They are also obligated under customary international law to not harm the environment of other States, and are held by international human rights treaties to take positive action on mitigation and adaptation to climate change.

Prof Voigt, specifically argued that: ‘Every State has the obligation under international law to do its utmost to reduce greenhouse gas emissions aligned with holding warming to 1.5 degrees, to limit any overshoot as much as possible, and to reverse it.’

IUCN and IUCN NL organized a joint event

Following the public hearing at the ICJ, IUCN and IUCN NL, in collaboration with Leiden University, organized an event to discuss the nature of the proceedings before the ICJ, the potential impact of its Advisory Opinion, and how it relates to similar opinions from other international courts, particularly the International Tribunal for Law of the Sea (ITLOS) and the Inter American Court for Human Rights (IACtHR).

‘It was encouraging to see that so many people join both online and in person on a Friday evening to engage in discussions about these important proceedings and to share insights on the urgent issue of climate change and its devastating effects on nature and vulnerable communities, such as those living on Vanuata, who initiated these proceedings before the ICJ’, said Antoinette Sprenger, senior expert environmental justice as IUCN NL

ICJ to deliver its Advisory Opinion in 2025

The International Court of Justice is set to deliver its Advisory Opinion in 2025. Although the opinion will not be legally binding, it will carry significant weight, sending a powerful signal to States hopefully for a stronger accountability and enhanced cooperation to stop the further progression of climate change.

Read more:

• IUCN argues at World Court that States have a legal obligation to fight climate change – Press release | IUCN
• EXPLAINER: The International Court of Justice considers climate change – Story | IUCN