Hungary’s Constitutional Court, in Budapest. Photo by Thaler Tamas.

In early June, Hungary’s Constitutional Court—the country’s top court—struck down parts of the country’s climate law for being too weak. The court ruled that the law as currently written violates fundamental principles of inter-generational justice, precaution and prevention of harm.

The decision was the result of a petition filed in 2021 by fifty opposition MPs - a quarter of Hungary’s parliament. They argued that a goal to cut national greenhouse gas emissions by 40% by 2030 compared with 1990 levels set out in the Climate Protection Act 2020 was far too weak. And they said the law had no plans to tackle climate adaptation, in breach of laws intended to protect Hungarian citizens.

The idea to go to court came from Erzsébet Schmuck, then an MP and co-leader of Hungary’s Green Party (LMP) who was chair of the parliament’s Committee on Sustainable Development.

The Hungarian government under populist prime minister Viktor Orbán has tried to sell itself on the world stage as a climate leader, saying it is an advocate of clean power and offering to share its expertise in water management. It was the first member of the European Union to ratify the UN Paris Agreement on climate change, and has made significant strides in boosting its solar energy.

Opposition MPs have never been convinced by the rhetoric. Schmuck told Drilled that she did not buy the government’s attempt to dismiss its responsibility to cut emissions on the basis of being a relatively small global emitter. And too little attention was being paid to how climate impacts were already playing out on the ground.

But “politics impacts everywhere” in Hungary, said Schmuck. When a national climate bill was put forward by opposition parties, said Schmuck, it was already a poorer version of a law drafted several years earlier. And opposition MPs said the later proposal was further hollowed out by the right-wing ruling party Fidesz in “an act of outrageous cynicism” to the point that it bore “no resemblance” to the original text. “Hungary had a new climate change law,” said Schmuck. “But it's for nothing, nothing, nothing.”

The wave of climate litigation sweeping the world in response to frustration at the lack of political action helped motivate the legal petition. A year earlier, in 2021, Germany’s Constitutional Court had ruled that the country's climate law was unconstitutional because it postponed serious emission cuts until after 2030 and did not explain clearly how they would be achieved after that. Doing so, it said, violated the fundamental rights of people in the future who would have much bigger burdens imposed on them. The case, fronted by the 23-year-old climate campaigner Luisa Neubauer, made headlines around the world and Hungarian environmentalists were keen to follow its model.

The Hungarian petition was filed in 2021 and dragged on for years with no sign of a conclusion. In 2024, after the European Court of Human Rights ruled that Switzerland’s failure to do enough on climate violated the human rights of a group of older Swiss women, Hungarian opposition MPs filed a supplementary petition arguing that the climate law breached international rules too.

Finally, in early June 2025, the court announced its decision, ruling that the 2030 target was “not aligned with the ongoing severity of climate change and the climate protection objectives of the international community and the European Union”. Most importantly, it did not align with the Fundamental Law of Hungary— essentially its constitution—which provides for the protection of natural resources, the right to physical and mental health, and the right to a healthy environment.

The court said legislators must maintain a high level of climate protection in accordance with the precautionary and preventive principles. And they must make commitments that take into account “the interests of present and future generations equally and with equal weight”.

In practice it had to put in place new rules to mitigate national greenhouse gas emissions and to help the country adapt to an increasingly unstable climate. It gave the government just over a year— until 30 June 2026— to fix the problems.

The Hungarian government did not respond to a request for comment.

Katalin Sulyok, associate professor in international law and sustainability at Durham University, who was involved in the case “in many ways”, told Drilled that the timing was unexpected, but the judgment itself followed the court’s previous rulings on environmental matters such as forestry.

Sulyok said the climate act passed in 2020 was a “paper tiger”, with very little actual content. The law set a long-term national target to be net zero by 2050, which was “really visionary and important”, but the interim target for 2030 was “overly lenient”. Hungarian emissions were already in decline because they are measured against years when the country was still under Communism and had a lot of heavy polluting industry.

The country has since changed dramatically, and in 2023 the government announced that it had met, and in fact surpassed, the 40% climate goal seven years early. Beyond that goal, said Sulyok, there were no “plans, procedures, deadlines, responsibilities, duties, anything” on how the country would now meet its 2050 target. “It really raised the risk that this net zero goal is just a symbolic pledge,” she said.

Sulyok, whose father Tamás is a former president of the Constitutional Court and the current president of the whole country, said the court sought interventions from the Hungarian Academy of Sciences and the country’s ten national park directorates. In particular it “actively reached out” to the Ombudsman for Future Generations, where Sulyok used to work and for whom she helped draft a submission.

“We don't have an environment ministry,” noted Sulyok, “so the court is sort of the first and last line of defense to step in.”

The decision was welcomed by Hungarian environmental groups, many of which sent amicus briefs of their own accord supporting the claim.

Friends of the Earth Hungary submitted three documents, one specifically from its youth branch. Executive president Ákos Éger said the decision “could lay the foundations for a meaningful climate policy in the short and long term.”

“The Constitutional Court is still one of the institutions with the highest public confidence in Hungary, so we [had] hoped for a balanced decision,” said Éger.

Magyarországi Éghajlatvédelmi Szövetség, the Hungarian Climate Protection Association, agreed that it was “an important step” in the right direction. The organization’s youth members had told the court that they viewed the climate law as a “generational injustice” because it shifted the crucial tasks of reducing emissions to the next generation.

Magyarországi Éghajlatvédelmi Szövetség added that the decision is in line with sentiment among the Hungarian public which is “increasingly concerned about the effects of climate change that threaten everyday life, such as extreme weather events or worsening drought.”

Hungary’s annual average temperature rose by 1.15°C between 1907 and 2017 - more than the global average - and the country has already seen changes in its rainfall patterns with resulting drought and flooding. A survey by the European Investment Bank last year found high domestic support for immediate investment in climate adaptation to avoid higher future costs, and most people saw it as an economic opportunity too.

How the ruling will be addressed remains to be seen.

Sulyok said the judgment does not set out what the interim target should now look like or what procedures legislators should follow. And, unlike some other climate judgments, which rely heavily on the reports of the Intergovernmental Panel on Climate Change (IPCC) to get a sense of what countries need to achieve, she said the Hungarian ruling is thin on the science.

Nor does it elaborate on how adaptation should now be approached.

Enforcement of previous Constitutional Court rulings, however progressive, has proved difficult, noted Sulyok.

But at least the court did not scrap the whole climate act, which would have flushed the net zero target baby out with the bathwater. Sulyok said the court “wanted to be helpful” and had to use some conciliatory language. “It's not a full-scale victory, but at least we have very aspirational legal principles: precaution, prevention, integration, equity, the duty to respect science. If we can cook something useful from all this, then this is when we will really win.”

Environmental NGOs have offered their support to parliament to help ensure that any new laws or policies set out “meaningful action across all areas of climate protection in the interest of both current and future generations”.

For Schmuck, who left parliament in 2022 and returned to her environmental roots in a part-time role with a green NGO, civil society has a key role to play to keep the ruling high in the public consciousness ahead of general elections next May.

She said that whoever wins control of the country will have little time to develop new regulations before the June deadline, so should be writing drafts now. “All parties who take themselves seriously [must] start to deal with it.”