Top UN court opens door for countries to sue each other over climate change

In a historic and potentially game-changing decision, the International Court of Justice (ICJ) has ruled that countries can sue one another over climate change, including for historic greenhouse gas emissions that have driven global warming.

Although the ruling, delivered Wednesday (23 July) in The Hague, Netherlands, is advisory and non-binding, legal experts believe it will carry significant weight and could reshape international environmental law, reports BBC.

The decision marks a major victory for climate-vulnerable nations and frontline communities who have long demanded accountability for the escalating impacts of climate change.

"This is a victory not just for us, but for every frontline community fighting to be heard," said Flora Vano from Vanuatu, one of the most climate-vulnerable nations. "Tonight I'll sleep easier. The ICJ has recognised what we have lived through — our suffering, our resilience, and our right to our future."

The case was originally proposed in 2019 by a group of law students from low-lying Pacific island nations, regions at immediate risk from rising seas and extreme weather events. Their initiative gained widespread support from developing countries frustrated by the slow pace and broken promises of global climate negotiations.

The ICJ, the UN's highest court, acknowledged that proving which country contributed to specific climate-related damages will be complex and must be handled on a case-by-case basis. However, the court reaffirmed that states have legal obligations under both the Paris Agreement and broader international law to take the most ambitious steps possible to reduce emissions and protect the environment.

Judge Iwasawa Yuji stated that failing to adopt such measures could constitute a breach of these legal obligations. He added that even countries not party to the Paris Agreement — such as the United States, which previously attempted to exit the pact — are still bound by international law to safeguard the climate system.

Campaigners hope this ruling will now pave the way for compensation claims from countries that have historically contributed the most to climate change. The court ruled that developing nations are entitled to seek damages for losses such as destroyed infrastructure and livelihoods due to climate-related disasters.

While determining specific accountability and calculating damages will remain complex, the court's opinion is expected to serve as a legal foundation for climate justice claims in the coming years.

According to a study published in Nature, the economic damage from climate change between 2000 and 2019 amounted to $2.8 trillion — or approximately $16 million every hour.

Joie Chowdhury, Senior Attorney at the Centre for International Environmental Law, called the ruling "a watershed legal moment."

"With today's historic ruling, the ICJ has broken with business-as-usual and delivered a historic affirmation: those suffering the impacts of climate devastation have a right to remedy — including through compensation," she said.

The decision is expected to influence future climate litigation, particularly as climate-affected nations seek accountability and reparation from high-emitting countries.