Common Law and Environmentalism: How the Necessity Defense has Adapted to Climate Advocacy

As climate change continues to cause more severe and frequent storms, raise surface temperatures at an alarming rate, and instigate concerning species extinction events, climate activists are getting increasingly frustrated. The world hasn’t seen a significant international climate policy success story since the Montreal Protocol 34 years ago, when all 198 United Nations Member States pledged to cut down on emissions of ozone-depleting substances to recover stratospheric ozone. Understandably, environmental activists are restless. Recently, they have turned to a means of progress that has the potential to solidify their demands forever: law. 

The American legal system is based on common law—a set of principles that have existed since before the country’s founding. In United States v. Schoon (1991), the Supreme Court solidified the four strict rules of a common law principle called the necessity defense. This defense requires one to demonstrate that “(1) he faced a choice of evils and chose the lesser evil; (2) he acted to prevent imminent harm; (3) he reasonably anticipated a direct causal relationship between his action and the harm averted; and (4) he had no reasonable lawful alternatives to breaking the law.” 

The necessity defense is mainly used in criminal cases where defendants will argue that they were in an emergency situation that necessitated breaking a law to prevent further harm (i.e. driving 30 miles per hour over the speed limit in order to rush someone to the hospital who would have died otherwise). The necessity defense is crucial in maintaining a just society as it protects citizens who had no choice but to violate the law. 

When on trial, climate activists have turned to using the necessity defense in a way that has come to be known as the “climate necessity defense.” Most commonly, the use of this defense is associated with civil disobedience, which is a deliberate violation of the law, often in the form of peaceful political protest. To use the climate necessity defense, activists will break laws, go to court, and argue that climate change is the emergency that allowed them to commit an act of civil disobedience. They claim that no lawful alternatives existed because U.S. government action on climate change has been so slow and ineffective. Activists get convicted for a variety of climate-related demonstrations, like sit-ins, blocking trains from transporting fossil fuels, and impeding construction of fossil fuel infrastructure. And though the use of this climate necessity defense may sound like a feasible idea, its success rate in court has been far from perfect. 

One failed example of the climate necessity defense can be seen in Montana v. Higgins (2020). In 2016, climate activist Leonard Higgins cut a chain to gain access to the Spectra/Enbridge pipeline facility in Chouteau County, Montana, where he manually shut off the flow of tar sands oil through the pipeline. Higgins committed this act of civil disobedience because of his concern about climate change and the slow means of the government to address it. Due to these actions, he was charged with a misdemeanor for criminal trespassing, and a felony for criminal mischief. When Higgins went to court in 2018, he used the climate necessity defense. During his trial, he presented expert scientific evidence on climate change and expressed his concern with America’s incredibly slow progress in creating environmental legislation, especially on fossil fuel energy policy. 

The State of Montana prevented Higgins from using the necessity defense by claiming that his actions to shut the pipeline down did not abate evil, that there existed other legal alternatives, and that there was a “lack of immediacy in the harm.” The court also claimed that Higgins was seeking publicity and trying to put “U.S. climate energy policy on trial” and “shift responsibility to the government.” Similar outcomes resulted from People v. Berlin (2019), where the defendants were denied the necessity defense and convicted for misdemeanor trespass for blocking construction of a pipeline in New York, and in Minnesota v. Bol (2018), where climate activists blocked the connection of an oil pipeline to a bank and endured the same consequences. 

Though these court decisions are not uncommon, success stories do exist. In Florida v. Block (2018), activists aligned with Everglades Earth First! were charged with misdemeanors for unlawful assembly and trespass for protesting the construction of a power plant. Although the defendants were convicted and two of them received jail sentences, the court permitted the necessity defense in the case of climate change. Expert testimonies were presented by hydroecologist Sydney Bacchus, who spoke to the court about the power plant’s immense water requirements and the damages it would impose on aquifers, and oceanographer John Van Leer, who pointed to the effects of climate change in Florida and how the plant would affect the area. From this outcome, it is clear that scientific reasoning could be the final push in the legal arena for climate activists to succeed. 

As of now, however, the list of denied climate necessity defenses is much, much longer than the list of accepted ones. It appears as though there is a sweet spot in using the climate necessity defense––expert climate science testimony is required to prove imminent danger, and there must be a direct causal relationship between the act of protest and preventing climate change. To deny use of the defense, courts will often assert the difference between “indirect” and “direct” acts of civil disobedience, as Montana did with Higgins, or claim that there are other, legal ways to protest. But considering the speed at which climate change is affecting our planet, do activists really have the time to wait for bureaucratic processes? Shouldn’t they just shut that pipeline down? What is one little protest in the context of global climate disaster? 

The issue with using the necessity defense for these climate activist cases is that common law has been in place for ages, and the strict rules it entails have been ingrained in the court system since common law was the law. This has made it difficult for activists to use the defense on the basis of climate change because they are trying to apply modern scientific knowledge to an ancient way of thinking. This doesn’t mean that things can’t change, though. 

The late Supreme Court Justice, Ruth Bader Ginsburg, noted in her first argued case on the basis of sex that “the times have already changed, and now it is time to change the law.” There is a parallel here between women’s rights and climate change; at this moment in time, climate change is a widely-accepted phenomenon that has been expertly and continuously proven by scientists. But the law doesn’t exactly reflect that consensus. The time has come for courts to consider the weight of the climate emergency and the connection of these activists’ demonstrations to their end goals. When used correctly, the climate necessity defense provides an excellent opportunity for what is needed most in climate policy right now––harmony and cooperation between science and law. 


Climate Defense Project. (2019, March 28) Climate Necessity Defense Case Guide: A Guide for Activists and Attorneys. Retrieved 5 November 2021, from

Climate Disobedience Center. (2017) The Climate Necessity Defense: A Legal Tool for Climate Activists. Retrieved 5 November 2021, from

Corbett, C. (2020, April 28) Asserting “Climate Necessity” in Defense of Civil Disobedience. LegalPlanet. Retrieved 5 November, 2021, from

Jackson, F. (2021, July 12) Is The Law The New Arena For Climate Action? Forbes. Retrieved 5 November, 2021, from

Justia. (2021, October) Necessity Defense in Criminal Cases. Retrieved 5 November, 2021, from

Long, L.N. and Hamilton, T. (2019, February 10) The Climate Necessity Defense: Proof and Judicial Error in Climate Protest Cases. Stanford Environmental Law Journal. Retrieved 5 November, 2021, from

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Montana v. Higgins, No. DC-16-18 (12th Jud. Dist. Ct., Chouteau Cty., Mont. Apr. 11, 2017).

United States v. Schoon, 939 F.2d 826 (1991)

People v. Berlin (Jan. 8, 2019, Town of Cortlandt Justice Ct., N.Y, Jan. 8, 2019)

Minnesota v. Bol (Sixth Jud. Dist. Ct., St. Louis Cty., Minn., No. 69DU-CR-18-166, Dec. 14, 2018)

Florida v. Block (Fifteen Dist. Ct., Palm Beach Cty. Ct., Fla., 08MM003373AMB, Dec. 4, 2018)