A North Dakota jury this week found Greenpeace liable for defamation, conspiracy and other claims over its participation in the Dakota Access pipeline protests that lasted from 2016 to 2017, awarding developer Energy Transfer $660 million in damages. Legal experts warn the decision could significantly deter other environmental groups from protesting oil and gas companies and their infrastructure around the U.S.

"The potential for liability itself will have a chilling effect,” said Jennifer Safstrom, an assistant clinical law professor at Vanderbilt University.

Josh Galperin, an associate law professor at Pace University, described the verdict as "unprecedented” and the amount of damages as "absolutely enormous.”

As climate change has worsened, activists in the U.S. and across the globe have repeatedly taken to the streets, forests and waters to put their bodies in the way of active fossil fuel production and new developments. Energy Transfer’s legal win shows that challenging protest groups in court can be successful — and it may inspire other companies to follow suit.

"The verdict is an invitation to other companies to take similar actions against protestors,” said Michael Gerrard, founder and faculty director of Columbia University’s Sabin Center for Climate Change Law.

Greenpeace announced it would appeal the verdict against its entities Greenpeace Inc., Greenpeace Fund and Greenpeace International. The environmental group did not respond to a request for comment, but Laura Handman, one of the lawyers on the case, said "this story is not over,” noting that Greenpeace International last month filed a countersuit against Energy Transfer in the Netherlands.

"That Greenpeace has been held responsible for breaking the law is a win for all of us,” Texas-based Energy Transfer said. The company had argued that Greenpeace incited protests that cost it millions of dollars, maligned its reputation and hampered its ability to raise money from capital markets.

Greenpeace and some legal scholars have described the suit as a type of legal maneuver known as a strategic lawsuit against public participation (SLAPP). Rules related to SLAPP suits vary state by state, but most have laws in place to protect activist organizations from large corporations pressuring them to back down. North Dakota is not one of those states, making it easier for Energy Transfer to have pursued the case against Greenpeace there.

Legal experts emphasized the importance of advocacy groups making sure they understand the specific laws in the states where they are organizing.

"For the environmental or nonprofit organizations supporting advocacy, it’s really important that they understand their state laws and their rights when it comes to the organized actions and potential anti-SLAPP lawsuits,” said Caroline Chen, director of environmental justice at New York Lawyers for the Public Interest.

The Dakota Access pipeline protests started in April 2016, with the Standing Rock Sioux Tribe setting up camp along the proposed route protesting its development and raising concerns about potential environmental impacts. Months of growing protests prompted President Barack Obama’s administration to block the project in late 2016. But soon after U.S. President Donald Trump took office in 2017, he reversed the decision and the pipeline was completed that year.

In the wake of the protests, North Dakota passed four laws between 2017 and 2019 increasing the penalties imposed on people who engage in various forms of civil disobedience, including those that specifically target oil and gas infrastructure. The oil and chemical industries, including Energy Transfer, lobbied for those laws. Since early 2019, 18 other states have also passed similar laws that create steep penalties for energy protestors, according to tracking by the International Center for Not-for-Profit Law.