Big Climate Litigation Cases to Watch in 2025

2025 is promising to be a big year for climate litigation, with forthcoming landmark cases and advisory opinions. Below, we have rounded up significant cases and developments across various categories that we expect will dominate climate and environmental litigation this year, including international cases and national cases with potentially far-reaching impacts.

1. International Cases

International courts are playing a critical role in addressing the intersection of climate change and human rights. Two advisory opinions and one new climate case at the European Court of Human Rights are set to further shape state accountability for climate change.

Advisory Opinions by the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACtHR)

Two significant advisory opinions are anticipated in 2025, which could reshape international legal frameworks on climate change and human rights: 

• The ICJ advisory opinion expected in 2025 will address states' obligations under international law to protect the climate system from human-caused greenhouse gas emissions, focusing on their duties toward present and future generations. It will also explore the legal consequences for states whose actions or omissions have caused significant harm, with particular attention to vulnerable small island states and global inequalities in emissions contributions.

• The IACtHR is expected to deliver its advisory opinion on the climate emergency and human rights in early 2025. This opinion is expected to clarify the scope of State responsibility for mitigating climate change under regional human rights law and set precedents for environmental protection as a critical component of safeguarding human rights. It could also reinforce the connection between climate change and the rights to life, health, and a healthy environment, offering guidance for domestic courts and regional bodies in addressing climate litigation.

Müllner v Austria at the European Court of Human Rights

The case of Müllner v. Austria is expected to make progress in 2025 after being granted priority by the European Court of Human Rights. Austrian citizen Markus Müllner, who suffers from multiple sclerosis (MS), filed the application on April 8, 2021, alleging that Austria’s failure to adopt effective climate measures violates his human rights under Articles 6, 8, and 13 of the European Convention on Human Rights (ECHR). Mr. Müllner’s MS symptoms, particularly Uhthoff’s syndrome, worsen with rising temperatures, leading to mobility issues and temporary paralysis. He argues that Austria’s insufficient efforts to mitigate climate change, including greenhouse gas emissions reductions, directly threaten his physical and psychological health. He also contends that Austrian law lacks effective remedies to challenge administrative or legislative inaction on climate change. After exhausting national legal remedies, including an unsuccessful challenge to tax benefits favouring the aviation industry over railways, Mr. Müllner brought his case to the ECHR. The Court initially adjourned the case in 2022, pending the outcomes of key climate cases before the Grand Chamber (Duarte Agostinho, Verein KlimaSeniorinnen Schweiz, and Carême).

2. Cases on Transnational Liability

These cases emphasise the principle of parent company liability, holding corporations accountable for environmental harms caused by their subsidiaries abroad. They reflect the global reach of corporate activities and the efforts of affected communities to pursue justice across jurisdictions, challenging parent companies to take responsibility for the actions of entities within their control.

Mariana Dam Lawsuit

In 2015, the collapse of the Fundão tailings dam near Mariana, Brazil, caused an environmental disaster, releasing 60 million cubic meters of toxic mining waste. This catastrophe killed 19 people, devastated entire communities, and displaced thousands. BHP, an Australian mining giant, now faces a record mass lawsuit in London, brought by approximately 620,000 claimants. The plaintiffs seek justice and compensation for the environmental and social damages caused by the disaster. The case entered the court stage back in October 2024 and is set to continue in 2025. The legal case hinges on two arguments: first, that BHP is strictly liable for the dam’s collapse due to its 50% stake in the Samarco joint venture; second, that BHP’s actions, such as pressuring Samarco to increase production, contributed to the disaster. The case is a great example of extraterritorial climate justice, where victims pursue accountability for corporate misconduct beyond their national borders.

Nigeria Oil Spill Litigation

2025 will also see the full trial initiated by two Nigerian communities, Ogale and Bille, who allege devastating oil pollution caused by Shell’s Nigerian subsidiary, SPDC. The UK Court of Appeal overturned a 2024 High Court ruling that required the claimants to prove Shell’s sole responsibility for 100% of the pollution under a "Global Claim," a standard typically applied in construction disputes. This approach was deemed by the appellate judges as an overly burdensome and impractical method for environmental claims. The trial will now focus on lead cases that represent the broader issues faced by the communities, a more efficient and just way to handle the claims. The case has been decades in the making due to repeated delays caused by Shell. The oil spills in question therefore date back to the 1980s.

3. Climate Lawsuits

Climate lawsuits challenge governments and corporations to take meaningful action on climate change. These cases often involve individuals or organizations demanding accountability for failing to protect the environment and human rights.

Belgium Farmer Lawsuit

The climate lawsuit brought by Belgian farmer Hugues Falys and three NGOs (FIAN, Greenpeace, and the Ligue des droits humains) against TotalEnergies will return to court for oral arguments on November 19 and 26, 2025. Falys, a farmer from Hainaut, initiated the lawsuit on March 13, 2024, citing severe damage to his farm caused by extreme weather events linked to climate change. On March 29, the three NGOs formally intervened, aiming to hold TotalEnergies accountable for its role as Belgium's leading fossil fuel producer and a major contributor to global greenhouse gas emissions. Together, they are demanding that the company implement a credible climate transition plan. This plan would require TotalEnergies to halt investments in new fossil fuel projects and reduce its oil and gas production by 75% by 2040.

Japan Climate Lawsuit

Japan’s major corporate climate lawsuit will be back in the Nagoya District Court on 18 February 2025, as 16 youth plaintiffs challenge 10 Japanese energy companies. The lawsuit, filed in August 2024, argues that the defendants' carbon-intensive practices violate the plaintiffs’ human rights, including the right to life, health, and self-determination, under the Japanese Constitution and tort law. The plaintiffs highlight Japan’s vulnerability to climate disasters, citing extensive scientific data and international climate commitments like the Paris Agreement, which mandates significant emissions reductions. The complaint asserts that the defendants’ reliance on coal and insufficient decarbonization strategies exacerbate Japan’s climate risks and fail to align with global targets to limit warming to 1.5°C. The plaintiffs argue that companies have a legal obligation to reduce emissions to prevent human rights violations and extend this responsibility to include Scope 3 emissions. It will be especially interesting to hear how another court interprets corporate climate accountability in light of the Milieudefensie v. Shell ruling in November 2024.

4. US Climate Deception Lawsuits

 

These lawsuits tackle corporate misinformation and deliberate attempts to mislead the public about climate change. They aim to hold companies accountable for decades of deceit that delayed critical environmental action.

Multnomah Country v ExxonMobil

Multnomah County, Oregon, has filed a lawsuit against a range of defendants, including fossil fuel companies, oil and gas industry trade associations, a utility company, and the consulting firm McKinsey & Company, Inc., seeking accountability for the harm caused by anthropogenic climate change. The lawsuit alleges that the defendants engaged in a decades-long campaign to promote fossil fuel products while concealing their knowledge of the environmental and human impacts. The County has incurred over $50 million in damages so far and anticipates at least $1.5 billion in future damages. In addition to compensation, the County seeks to establish a $50 billion abatement fund to address and mitigate ongoing and future climate impacts.

People v. ExxonMobil Corp.

California Attorney General Rob Bonta filed a lawsuit against ExxonMobil, accusing the company of contributing significantly to plastic pollution and misleading the public about the viability of recycling solutions. The lawsuit alleges that ExxonMobil promoted "advanced recycling" technologies as effective in addressing plastic waste, despite internal evidence showing the process yields less than 0.1% recycled content. Claims about greenhouse gas reductions were also based on selective data and flawed assumptions, misleading consumers about the environmental benefits. The lawsuit contends that ExxonMobil has perpetuated the plastic crisis by falsely portraying single-use plastics as recyclable and overstating the potential of advanced recycling technologies, such as pyrolysis. California’s claims include public nuisance, water pollution, false advertising, and unfair competition. The lawsuit seeks an abatement fund worth billions to address the harm caused, as well as orders to prevent ExxonMobil from making misleading public statements about recycling.

Anti-Climate Action Lawsuits

Not all lawsuits support climate action—some aim to challenge or undermine environmental regulations. These cases reflect the ongoing tension between economic interests, government oversight, and the fight against climate change.

Texas v. Blackrock

In late 2024, Texas Attorney General Ken Paxton led a lawsuit, joined by 10 other states, against BlackRock, State Street Corporation, and Vanguard Group, accusing the firms of conspiring to manipulate the coal market through anticompetitive practices. The lawsuit alleges that these firms, through their significant holdings in U.S. coal producers, pressured the companies to reduce coal production in line with their "green energy" commitments, using initiatives like the Net Zero Asset Managers Initiative and Climate Action 100+. This coordinated effort, the lawsuit claims, artificially restricted coal supply, increasing electricity costs for consumers while boosting the firms’ profits. The complaint also accuses BlackRock of misleading investors by claiming that its non-ESG funds would prioritize shareholder value, despite using its holdings to advance climate agendas. The lawsuit seeks declaratory and injunctive relief, damages, and civil fines or penalties, including divestiture to prevent further anticompetitive actions.

Iowa v. SEC

In Iowa v. SEC, the Eighth Circuit is evaluating the legality of the SEC’s new climate-related disclosure rule, which mandates that companies disclose information about climate risks, mitigation plans, and emissions. The rule, issued in March 2024, has faced challenges from several states and corporations, who argue that it violates the "major questions doctrine." This doctrine questions whether agencies have the authority to implement rules that significantly alter their historical scope. Critics contend that the SEC lacks authority to require non-financial disclosures, arguing that the rule shifts focus from financial performance to a company’s climate reputation. Beyond this, the case also raises First Amendment concerns about compelled speech. Critics argue the rule forces companies to adopt the SEC's climate policies, while the SEC may counter that the disclosures are factual and not unduly burdensome.