To raise awareness about climate change and urge authorities to act, climate protesters have recently employed creative but unlawful tactics. From blocking roads and sit-down strikes to glueing themselves to streets, throwing soup at museum artefacts, or attaching their hands to a conductor’s desk during a concert—these striking acts are, at their core, criminal offences. As a result, many protesters face prosecution. In their defence, they argue that their actions were necessary to prevent a grave and imminent danger to the environment and should be legally justified under the doctrine of necessity. This paper examines whether such arguments hold legal ground within the criminal law frameworks of Germany and the United States. While the legal standards for necessity may vary slightly between jurisdictions, they generally require the presence of a grave and imminent danger, a threat to a legally protected interest, that the danger is not self-induced, a causal connection between the danger and the act, the absence of legal or practical alternatives, proportionality between the act and the threat, and that the individual is not obligated to endure the danger. For climate protests to be justified under necessity, these criteria must be satisfied. This paper briefly outlines how these principles are interpreted in German and US criminal law and assesses whether climate activism, in its current forms, can meet these legal standards.