 Cindy Cho is a law professor at Indiana University and a former federal prosecutor. In a new memo, she and collaborators at Public Citizen suggest the cause can be traced to fossil fuel companies. Last summer's unprecedented heat in Arizona would have been nearly impossible without human-caused climate change. Oil companies played a major role in that. And people died from the heat. Link all those together, Cho says. And there we've got that first element, right? The defendant caused the victim's death.