Landmark climate hearings conclude at world's top court

When Cynthia Houniuhi looked into the eyes of judges at the International Court of Justice (ICJ) in the Netherlands last week, she had one image burning in her mind. 

While delivering her testimony on the opening day of the historic climate case at The Hague, she could see the wooden posts of empty houses standing in salt water on the island of Fanalei, where her family is from on the Solomon Islands. 

"The island looks deserted and abandoned compared to the one I grew up seeing and portrayed by my grandma's bedtime stories," 29-year-old Houniuhi told DW.

Rising sea levels, driven by climate change, pose an existential threat to those who call low-lying Pacific Islands like the Solomons home. Despite contributing 0.02% of the greenhouse gas emissions driving global temperature increases, they are among the most vulnerable nations in the world to the climate crisis. 

Low-lying islands like Tuvalu, Vanuatu and the Solomon Islands are particularly vulnerable to sea level riseImage: Mario Tama/Getty Images

Landmark climate case

And it was these feelings of injustice and urgency that drove Houniuhi, who is president of the campaign group Pacific Island Students Fighting Climate Change, and many other young people to spearhead calls to bring the issue straight to the world's top court. 

What started as a classroom discussion five years ago on the Pacific Island of Vanuatu, has in the last two weeks brought representatives from over 100 nations and international organizations to deliver testimonies at the largest ever case before the UN court. 

In 2023, the UN, led by Vanuatu, specifically requested the international court adjudicate on climate responsibility, having expressed "profound alarm" that greenhouse gas emissions continue to rise despite vows to cut them drastically. 

The court has been asked to provide an advisory opinion on the duties states have under international law to protect the climate. They've also been asked to address what the legal consequences are for those who "by their acts and omissions, have caused significant harm to the climate system." 

The court has witnessed powerful testimonies of how rising temperatures, largely driven by greenhouse gases emitted by burning fossil fuels, are devastating lives on the frontline of the crisis. 

But we are not looking for sympathy, explained Houniuhi. "We're looking for fairness, fairness in the laws that are supposed to govern us."

Nearly every country has ratified the 2015 Paris Agreement — a legally binding treaty aiming to limit temperature rise to 1.5 degrees Celsius (2.7 Fahrenheit). Still, emissions are at record highs. Under current policies, the world is on track for over 3C warming, with catastrophic climate consequences. 

Activists protesting at the UN COP29 summit in Azerbaijan last monthImage: Aziz Karimov/REUTERS

Big emitters highlight Paris Agreement 

Countries speaking at the hearings included some of the world's largest current and historical emitters of greenhouse gases such as the US, China, and Russia. 

"These states have not only enabled but proactively encouraged the production and consumption of fossil fuels and continue to do so today," said Houniuhi. 

The hearings come on the heels of what was seen by many climate vulnerable countries as a betrayal at the annual UN climate summit in Azerbaijan. Wealthy, industrialized nations agreed at the summit to provide at least $300 billion for low-income countries to fight climate change — far below the sum of at least $1 trillion per year they argued was necessary. 

One of the most striking aspects of the case is the divide that has emerged between big polluters and the rest of the world, said Nikki Reisch, climate and energy program director at the Center for International Environmental Law (CIEL). 

Many at the UN court argued big emitters need to be held accountableImage: Rupert Oberhäuser/picture alliance

"Fossil fuel giants and major polluters found themselves isolated in their attempts to sweep their historical responsibility for the climate crisis under the rug and claim that their legal obligations start and end with the Paris Agreement," said Reisch.

CIEL said that major polluters claim the current UN climate regime, which includes the Paris Agreement, is the only relevant existing international law on states' climate obligations and it requires them to do very little. CIEL instead urged the top court to look beyond Paris to the "wider universe of international law" encompassing environmental and human rights law.  

Polluters should face accountability

But speaking at The Hague, Margaret L. Taylor, legal adviser at the US State Department, said the US wanted the court to judge in a way that "preserves and promotes the centrality" of existing treaties, primarily the Paris Agreement.

Taylor said the court should not weigh whether countries have "violated obligations" in the past regarding climate policy. "Nor would it be appropriate," she said, for the court to decide whether states have a "responsibility for reparations." The US has contributed most to global CO2 emissions since humans started burning fossil fuels.

China, the current biggest emitter, as well as fossil fuel powerhouse Australia, also insisted UN climate negotiations should remain the "primary channel" to govern action. 

Many states most vulnerable to climate change have contributed little to global emissionsImage: Omer Faruk Cura/Andalou/picture alliance

Several countries including Vanuatu, Fiji and Costa Rica argued for climate reparations proportionate to climate harms. 

Julian Aguon, an indigenous human rights lawyer involved in the proceedings, said it has been deeply heartening to see the vast majority of participants agree that the conduct that's causing climate change is unlawful, must stop immediately, and that those responsible must remedy any harm caused. 

"This shared legal and moral clarity could not arrive at a more perfect time. Indeed, if the past two weeks could be summed up in three words, it might be, 'behold the many'," said Aguon. 

Pacific Island nations emphasized rising sea levels presented an existential threat to themImage: Christopher Furlong/Getty Images

What impact could a top court decision have? 

After hearings at The Hague ended Friday, a court decision is expected early next year.

While its opinion is not binding, it is expected to have wide repercussions in clarifying states' obligations under international law, as national courts often look to the top court for guidance. 

"The ICJ's opinion could shape the trajectory of global climate litigation, paving the way for a new era of decisive action to tackle the global climate crisis," said Joy Reyes, climate justice lawyer and policy officer at the London School of Economics' Grantham Institute. "As the world's highest court, the world court's proceedings carry significant authority and moral weight."

Even before a decision is reached, campaigner Houniuhi called the proceedings a milestone in climate justice as the first time the voices of frontline communities will be weighed equally alongside those of major polluters. 

Now the judges have the power to course correct on climate change, she said. "And it's not too late."