It is, in short, an unprecedented legal case addressing what many recognize as the greatest challenge of our time – the global climate emergency. And for small island developing states and other nations on the frontlines of this emergency, their very survival is literally on the line.

“We find ourselves on the frontlines of a crisis we did not create, a crisis that threatens our very existence,” Vanuatu’s special envoy for climate change and environment Ralph Regenvanu told the court in his opening statement. Underscoring the gravity of the situation and the significance of pursuing justice through these proceedings, he said: “This may well be the most consequential case in the history of humanity.”

Vanuatu and a handful of other similarly situated small island and most climate-vulnerable nations delivered powerful testimony on the opening day of the ICJ climate hearings that spoke to their existential peril and frustration with ongoing UN climate negotiations as well as their demands for accountability from high-emitting countries most responsible for the climate change problem.

“The time for empty promises has passed,” a representative for Bangladesh told the court. The current UN framework governing international climate negotiations is grossly insufficient for halting dangerous global heating and protecting the most vulnerable countries, these states say.

Speaking at a media briefing, Regenvanu said Vanuatu and other small island states have been “continually frustrated” by the UN Framework Convention on Climate Change (UNFCCC) process that has played out over the last 30 years. “Coming to the International Court of Justice, we are trying to find another way to get climate action that we need…that science says we need, but which so many countries through the power of political convenience and the fossil fuel lobby refuse to take action on”.

Regenvanu and several others who testified reminded the court that the climate change problem has been known by powerful countries like the United States since at least the 1960s, referencing a 1965 warning from former president Lyndon Johnson, for example, that recognized “a steady increase in carbon dioxide through the burning of fossil fuels.”

The continued production and consumption of fossil fuels – oil, coal, and gas – despite clear understanding of the catastrophic climate consequences, is at the heart of the problem, Pacific Island communities argued.

Professor Jorge Vinuales, speaking on behalf of Vanuatu and the Melanesian Spearhead Group, noted that the International Energy Agency has said that realizing net-zero greenhouse gas (GHG) emissions by 2050 means no new fossil fuel development (starting in 2021).

Yet the fossil fuel production plans of countries seemingly ignore that warning and would result in a level of emissions inconsistent with the goals of the Paris Agreement for limiting global temperature rise. “Large producing states are proactively expanding their fossil fuel production and consumption, playing lip service to their climate commitments,” Vinuales told the court.

He pointed out that fossil fuel subsidies from governments reached an all-time high of $7 trillion in 2022. “For decades, what we have seen from large-emitting and producing states is delay, low ambition, and in practice concrete plans to expand extraction and use of fossil fuels,” he argued. Such conduct, Vanuatu and other small islands states say, amounts to violations of international law.

“How can the conduct that has taken humanity to the brink of catastrophe, threatening the survival of entire peoples, be lawful and without consequences?” Vanuatu Attorney General Arnold Kiel Loughman asked the court. “The failure by a small number of large emitting states to fulfill these obligations constitutes an internationally wrongful act, triggering legal consequences under international law of state responsibility,” he  said.

Small island states pushed back and called out (though not by name) big polluters like Saudi Arabia. As one representative for Barbados said, many major emitting states “knew that all of our lives would become shorter, more brutish, and more vulnerable because of their decisions to promote fossil fuels.” And as L. Ryan Pinder, attorney general for the Bahamas, told the court: “It is time for these polluters to pay.”

“The devastation is undeniable,” Pinder said. “If we continue on our current path, my country will cease to exist.” His testimony explained climate change is already starting to ruin the Bahamas, from monstrous hurricanes to warming oceans and coral bleaching to rising sea levels. The vast majority of the country’s land, 80%, sits just 1.5 meters above sea level, and by the end of this century all its iconic sandy beaches could be gone. “The Bahamas is at risk of becoming uninhabitable,” he said.

Several other Caribbean states shared similar warnings of their dire circumstances. Kerrie Symmonds, a foreign minister for Barbados, said the climate crisis “is for us an imminent matter of life and death.” Gaston Browne of Antigua and Barbuda said the matter before the court “is not just a legal question. It is a matter of survival.”

The court is expected to hear from 110 parties in total, and the hearings will continue Tuesday and the rest of this week and will wrap up at the end of next week on December 13. The court’s advisory opinion could come later in 2025.