The world is eagerly awaiting the International Court of Justice’s (ICJ) advisory opinion on the obligations of states under international law to protect the climate system.

After years of dogged campaigning for environmental justice, some of the world’s most climate-vulnerable nations, mostly small island developing states and least developed countries, finally had their day in court at The Hague last December.

Testimonies before the ICJ in the advisory proceedings on climate change were informed by climate science, traditional and indigenous knowledge, and first-hand accounts of experiences under a changing climate.

As countries and climate campaigners await the court’s verdict, experts and scientists have presented evidence from powerful testimonies related to warming, sea level rise, cyclones, and human security submitted by states seeking strong climate action.

In their pleadings, a Pacific-led group of law students and diplomats led by the island state of Vanuatu wanted the ICJ to clarify what countries must do to address climate change, what legal repercussions they should face if they don’t and what “significant harm” is caused.

The vulnerable countries took their battle to The Hague, fed up with zig-zagging the world to get climate summits like conferences of parties (COPs) to take concrete action, usually coming away bitterly disappointed.

But at the ICJ hearings in December, high-emitting rich nations shielded behind the very same climate treaties underpinning the COP’s talks to quash pressure to step up their climate actions.

Seeking justice

Recent years have seen an increase in climate-related court cases and a deeper engagement of legal scholars and judicial bodies with matters related to the environment.

Children, elderly women, and non-governmental organisations have gone to court to bring about enhanced climate action, demanding environmental justice.

What is environmental justice (EJ)? The United Nations General Assembly and the UN Human Rights Council recognised the human right to a clean, healthy and sustainable development in 2022 and 2021, respectively.

The UN Development Programme (UNDP) has developed a global strategy for EJ to increase accountability and protection of environmental rights.  

Environmental justice is a social movement and a set of principles that aim to ensure that all people have access to a healthy environment and equal protection from environmental hazards.

This includes the right to access natural resources, protection from environmental harm and the right not to be disproportionately harmed by environmental policies, laws and regulations.

EJ also includes the right to access environmental information and the right to participate in decision-making processes that affect the environment.  

Environmental justice seeks to address environmental inequities that can harm marginalised communities, such as those caused by hazardous waste, resource extraction, other land uses and redlining (a form of discriminatory practice in which services—usually financial, such as mortgages and insurance—are withheld from people living in neighbourhoods of high racial and ethnic minorities’ proportion).

Highlighting testimonies at The Hague in the latest issue of the International Institute of Sustainable Development (IISD) Earth Negotiations Bulletin, Shaina Sada and Elisabeth Holland note that the awaited ICJ advisory opinion on climate change seeks to clarify states’ responsibilities to protect the climate system, and legal consequences under international law for failing to do so.

The request for the ICJ advisory opinion came from the efforts of Pacific youth who saw the impacts of climate change on their ocean and island homes and felt dismayed by the lack of urgency in the political process. Vanuatu formed a coalition to move the case through the UN.

Watertight case

The Intergovernmental Panel on Climate Change (IPCC) reports summarise global climate change knowledge.

In the decades since their inception in the early 1990s, the reports’ conclusions regarding the certainty of human impacts on the climate evolved from acknowledging the potential for human influence to the strong and unequivocal statement of human responsibility in the IPCC Sixth Assessment Report (AR6).

“The body of scientific knowledge within the reports has expanded dramatically, documenting compelling consistency of climate impacts among myriad lines of evidence,” Sada and Holland said.  

Complementing the scientific knowledge in the IPCC reports, states drew from additional expansive knowledge to build their testimonies.

This included cultural, Indigenous, and place-based knowledge, first-hand testimonies, expert reports, and peer-reviewed studies published since AR6 concluded.  

Earth’s temperature has increased on land, in the ocean, and in the atmosphere.

IPCC AR6 concluded Earth’s atmosphere has warmed on average 1.1°C since pre-industrial times.

The certainty of the scientific consensus on the causes and outcomes of warming was cited by many states, such as Sri Lanka.  

The rise in human-induced greenhouse gas (GHG) emissions, primarily from burning fossil fuels, unequivocally drives rising temperatures, as noted by states, including Kenya.

Testimony from nine member states of the Commission of Small Island States on Climate Change and International Law (COSIS), discussed the urgent need to phase out fossil fuels to meet international climate goals.

As temperatures rise, thermal expansion and melting land ice drive rising sea levels.

The Melanesian Spearhead Group testified to the disproportionate impacts on people who bear little responsibility for GHG emissions.  

Sea levels will continue rising for centuries, presenting stark challenges for present and future generations and coastal ecosystems.

The question of intergenerational equity is crucial, as Sierra Leone testified, noting the related need to achieve the Sustainable Development Goals (SDGs).

The rapid acceleration of sea level rise over time was also discussed in relation to state sovereignty.

Testimony from the Pacific Islands Forum (PIF) rejected the notion that coastal inundation could disrupt state sovereignty, instead stressing that international law should allow for the continuation of states in the face of rising sea levels.

The combined impacts of sea level rise, warming and cyclones are pushing communities beyond the limits of adaptation in atoll countries.

Testimonies from Tonga, Tuvalu and the Pacific Community illustrated the failure of high-emitting states to comply with the principles of common but differentiated responsibilities – and deliver climate finance commitments to support adaptation efforts in vulnerable countries.

Climate change challenges have broad implications for human safety and security.

The Sudan testified to people’s experiences with resource scarcity and displacement.

Palestine testified that military activity drives increasing emissions and that living under occupation poses extraordinary challenges to climate adaptation.

World Health Organisation (WHO) testified that future climate impacts will displace millions of people and exacerbate poverty.

ICJ heard that the effects of climate change, including warming, extreme events and rising sea levels, have devastating impacts which will continue into the future.

In 2024, the year the testimonies were submitted, the global temperature of 1.55°C above pre-industrial levels for the first time ever exceeded 1.5°C, demanding urgent action.

Pacific Island Students Fighting Climate Change told the court: “International law must serve as a compass for justice and responsibility… the pursuit of climate justice requires determining the obligations of states, but it is incomplete without the requisite legal consequences”.

The world awaits the ICJ’s advisory opinion, hopeful of a strong outcome informed by the myriad lines of scientific evidence in the powerful testimonies heard by the court.