PARIS, June 25, 2025 (BSS/AFP) - Legal efforts to block or unwind action on climate change are rising across the globe, new research showed Thursday, particularly in the United States which leads the world on anti-green litigation.

This trend was expected to intensify as the White House took "an increasingly aggressive stance" against environmental regulations, said the authors of the world's largest analysis of climate litigation.

As in previous years, most new cases in 2024 were filed by non-governmental organisations or individuals using litigation to advance broader climate aims, such as opposing fossil fuel projects.

But litigation was "increasingly used not only to advance climate goals but also to resist or reshape them", said the report by the Grantham Research Institute at the London School of Economics.

Sixty of the 226 cases filed in 2024 -- about 27 percent -- involved an argument not aligned with climate goals, said associate professor Joana Setzer, one of the authors.

This was a rise on 2023, when about one in five fell into this category, she said.

This reflected a growing political polarisation around climate action, she said, particularly in the United States where most of these cases occurred.

"The situation in the United States shows that litigation is a two-way street and can be used to help climate action and also to slow it down."

In recent years, litigants seeking to delay or prevent climate action had evolved from denying the science or need to respond to instead challenging how policy is implemented, the report said.

In 2024 in the United States, for example, there were at least five cases brought against government laws to introduce new energy efficiency standards for buildings, appliances or vehicles.

A growing trend toward anti-climate litigation in the United States "has already intensified" in the early months of President Donald Trump's second term and could be expected to continue, Setzer said.

Trump's executive orders to roll back climate action had already sparked federal lawsuits against four US states and a "wave" of counter litigation, the report said.

"It has become clear... that the courts will continue to be a critical site for contestation and challenge" to Trump's campaign against climate policy, the report said.