In 2002, a few months after 9/11, I published one of the very first academic examinations of environmental terrorism: what was included in this term and what wasn’t, who might commit such terrorism, and what sorts of environmental resources were vulnerable. Since then, it has been the subject of academic and government analyses. Now, twenty years later, it is time to revisit the concept in light of worsening anthropogenic climate change, the rise of authoritarian states and ecofascism, and gray-zone conflicts in international relations.