Trends

For ESG expert witnesses, the key takeaway is the dual trend of convergence and divergence in U.S. state-level climate disclosure bills. While states like California, New York, and others show convergence by adopting the Greenhouse Gas Protocol and requiring third-party assurance for Scope 1, 2, and 3 emissions, significant divergence exists in reporting thresholds, phase-in schedules for Scope 3, and penalty structures. This creates a complex compliance landscape, where expert testimony will be crucial to navigate the material differences in legal requirements and establish defensible reporting strategies across jurisdictions.

As an ESG-focused expert witness, the article "Is the Law the Last Bastion of Climate Action?" suggests that climate litigation is becoming a significant driver of corporate and government policy. Legal action is succeeding and forcing decision-makers to address climate science, which has been a major challenge in the environmental and governance aspects of ESG. The opinion by the International Court of Justice and other legal cases provide a strong basis for holding entities accountable, indicating that legal frameworks are now a critical tool for achieving climate targets. The article also touches on related ESG topics like just transition and human rights, highlighting the evolving and expanding scope of legal and regulatory risks for businesses.

Bayer is addressing U.S. litigation related to Polychlorinated biphenyls (PCBs), chemicals produced by the acquired company, Monsanto, until 1977. The lawsuits fall into three main categories: environmental impairment, property damage, and personal injury. Bayer has already settled with some municipalities and states, but continues to defend against other pending cases.

Over the past five years, environmental litigation has seen consistent activity, with a total of 2,591 lawsuits filed since 2020. Data shows that the United States of America is the most frequent plaintiff, responsible for nearly 20% of cases, or about 90 per year. Other key plaintiffs include prominent environmental groups like the Center for Biological Diversity and the Sierra Club. This litigation often involves key statutes such as the Clean Air Act and the Clean Water Act.

In June 2025, the U.S. Supreme Court's denial of certiorari in two key cases affirmed lower-court rulings, clearing the way for a potential surge in environmental citizen suits. This decision strengthens the ability of environmental groups to act as private attorneys general to enforce environmental laws and hold polluters accountable, which will increase compliance pressure and legal risk for businesses.

The trend in climate change litigation is shifting to target companies, not just states. This is based on a growing duty of care for corporations and their directors to protect against dangerous climate change, a trend that continues to evolve with recent case law. To mitigate mounting ESG litigation risks, including class actions, companies are advised to adopt a proactive and transparent stance on ESG matters by implementing appropriate corporate governance.

Cases on biodiversity and resource damage rise. Experts can cite due diligence failures, focusing on ecosystem impacts. Takeaways: Provide evidence on corporate responsibilities in global-US contexts.

Predicts rise in emissions-related suits against governments. Experts can draw on international obligations for US cases, focusing on air pollution's human rights violations. Takeaways: Use climate science to establish liability thresholds.

Expert witnesses can reference recent settlements like Hawai‘i's transportation emissions reduction plan and Brazilian lawsuits against thermoelectric plants for GHG emissions. Key takeaways include the need for detailed emissions inventories and interim targets, as seen in cases challenging water neutrality claims and fossil fuel projects. These provide precedents for quantifying hydrogeological impacts and supporting claims on water resource depletion in US and global contexts.

This snapshot details cases linking climate change to water resources, like droughts and pollution. Experts can draw on trends in polluter pays principles for hydrogeology testimony, focusing on emissions' role in altering water cycles. Key for US litigation: substantiate claims with scientific evidence on groundwater impacts and community rights.