The obvious question – how a Dutch lawyer becomes an adviser to a group of small islands in the middle of the Pacific and gets to lead that country's legal team in the largest court case ever – is answered matter-of-factly by Margaretha with ‘it just went very organically’.

In early 2015, she moved from London to Vanuatu to develop an environmental and climate law programme at the University of the South Pacific. At the time, she had just completed her PhD on state responsibility for climate change from a human rights perspective. Later that year, she and a group of her students travelled to France to assist small island states, including Vanuatu, in the negotiations for the Paris Climate Agreement. When it became clear that the Paris Agreement fell short of expectations, she was asked to work with an indigenous human rights lawyer from Guam, Julian Aguon, to devise a strategy for an international climate case.

It started with 27 law students

Vanuatu and the other small Pacific island states barely contribute to climate change, but they are already being severely affected by its impacts: stretches of coastal land have been swallowed by the sea, valuable coral reefs have died, devastating storms and changing weather conditions are costing people their lives while eroding livelihoods. Many small islands risk becoming completely uninhabitable if greenhouse gas emissions are not quickly and drastically curtailed

That is why 27 law students from eight Pacific island states started a campaign in 2019 to have the International Court of Justice in The Hague rule on climate change and human rights. The Vanuatu government supported the initiative and took it to the UN. An intensive diplomatic campaign followed, resulting in resolution 77/276, adopted by the UN General Assembly in March 2023.

Two main questions

This resolution asks the International Court of Justice to issue an advisory opinion on two legal questions, namely what are the obligations of states under international law to ensure the protection of both states and present and future generations from climate change and environmental degradation, and what are the legal consequences for those states that have failed to comply with these obligations, thereby harming both other, vulnerable, states and present and future peoples and individuals?

Margaretha explains: ‘While the Court has previously recognised that future generations matter and that states must protect the environment, including for generations to come, what exactly that means – and what rights future generations have – is still unclear.’

The strategy of concentric circles

Margaretha, who together with Julian heads the legal team for Vanuatu and the Melanesian Spearhead Group, knew that securing the requisite support from UN member states for a meaningful advisory opinion request would not be easy. She was therefore pleasantly surprised when, after a diplomatic campaign of some four years, that hurdle was cleared and the resolution could even be passed by consensus (without a vote). Margaretha: ‘In such a negotiation process, the challenge is to get a majority on board while keeping the formulated legal question as intact as possible.’

The strategy used by the team is one of concentric circles. Margaretha: ‘We first built support in the Pacific, then with all the other small island states, and later with other climate-vulnerable countries. Actually, with the climate-vulnerable countries on board, you already have a majority in the General Assembly. But we kept building the coalition by seeking support from other countries in various regions.'

The legal question was referred to the court in April 2023. All UN member states were then invited to submit written pleadings and respond to those of each other. Over a year and a half later, in December 2024, the hearings took place at the Peace Palace in The Hague, with the participation of a record number of 96 states and 11 international organisations.

Margaretha was among the first to speak: ‘It was almost surreal to be there with so many people from all over the world, completing the last piece of the process, at least the part in our hands.'

The underlying question

The opinion is expected this year. Asked what she hopes for, she smiles subtly and explains that behind their two main questions about obligations and legal consequences, there is another question that has not been explicitly asked but is of great importance.

Margaretha: ‘This is about the legality, or illegality, of the conduct of states – acts and omissions – that has caused climate change. Bearing in mind that science has warned about the risks of greenhouse gas emissions for decades. That ongoing conduct now threatens to make whole countries unlivable.'

It has never been legal

That is why climate-vulnerable countries have asked the court to clarify not only the content of international norms applicable to climate change, but also to assess states’ conduct over time in light of those norms.

Margaretha: ‘It is not just about what states must do now, about carbon budgets and fair share, but also about the fact that we are witnessing an ongoing violation of fundamental legal principles and rules. Recognising this violation is important not only from a justice perspective but also for the climate itself. Indeed, as soon as a violation is identified, a crucial legal conclusion follows: that violation must stop.'

'By acknowledging this, you get a very different discussion. States that have knowingly harmed the climate system and thereby breached international obligations incur international responsibility for such breaches.'

One of the parties advised by Margaretha's team is the Organisation of African, Caribbean and Pacific States. The 79 member states of this organisation have explicitly argued that colonial emissions should be included when calculating those historical emissions. This could mean multiplying the Netherlands' historical emissions by a factor of three, partly because of the large-scale deforestation in the then-Dutch East Indies.

The impact of the opinion

Margaretha hopes for as detailed an advisory opinion as possible from the Court: ‘The more specific the opinion is about what exactly is illegal and what the consequences are – and thus what should happen with, for example, fossil subsidies, regulation, technology transfer, and financing – the more impact the ruling will have.’

Although the Court's opinion is non-binding, she finds that term almost misleading, as the opinion is a clarification of existing law that states are obliged to follow. Margaretha: ‘If states refuse or neglect to do what the Court indicates, they violate their obligations.’ She notes that the exact impact of the ruling will be difficult to track, as in many countries decision-making on implementation takes place behind the scenes. Any policy adjustments will not necessarily be attributed to the ruling.

It's different for courts; judges in other climate cases worldwide will likely be guided by the Court’s opinion, and this will probably be explicit. In political debates, public campaigns, and activism, too, the impact of the opinion could become quite visible.

Pride and hope

In Vanuatu, Margaretha says, people feel especially proud that such a small country – with one-third the population of Amsterdam – has managed to pull this off. Because the climate negotiations have so far produced too little, the inhabitants simply cannot help but hope that this case will make a difference. Margaretha: ‘The initiative comes from the indigenous youth movement, and the process is not politicised. There is little cynicism to be found.'

When asked about her own feelings on both the fate of Vanuatu and other climate-vulnerable countries and international law in general, she is quick to point to reasons to remain hopeful. She does see these, despite the new US ‘drill, baby, drill’ president using or overruling international law at will, and the decision of several major US banks and asset managers to exit climate organisations already in the run-up to Trump's inauguration.

Margaretha: ‘When Trump stepped out of the Paris Agreement during his first term in office, numerous US states and cities formed a coalition to continue to comply with the treaty. We see that happening again now, and not just in the US. Around the world, citizens, organisations, businesses, and governments are uniting to counter the attack on fundamental rights and environmentalists.'

'It is too early to conclude that international law – or law in general – will lose out. In fact, the strengths and weaknesses of our legal systems are laid bare in tumultuous times like these. And in many cases, we see that judicial bodies refuse to blow with political winds. That gives hope!'

Enduring legacy

Margaretha is only 39, but does not have to think long about what would give her the greatest satisfaction when looking back at the end of her career.

Margaretha: ‘Above all, I hope to have encouraged my students to use their imagination and follow their moral compass in their chosen profession. If students feel inspired to express the values that matter most in their own way, as lawyers or otherwise, that is the most lasting legacy I can leave.

Students have such bright ideas; their insights are important, and maybe they know better than I do. I encourage them to look beyond the textbook, to rely on their critical thinking skills, but above all not to be afraid and never to feel too lowly. And precisely when it comes to climate, the youth of today and tomorrow have every right to speak!'

Elles Tukker