I came to view my work with Hiroshima survivors in 1962 as not only a scientific study but a form of bearing witness to what the bomb did to human beings in that city. I tried to bring professional knowledge and experience to that effort, to become what I later called a witnessing professional. Nuclear and climate issues interacted in that early study, and have continued to be inseparable for all of us. I draw upon examples of witnessing professionals over the course of our struggles with these two planetary threats. In each case, they had to expose and combat the malignant normality, the dangerous prevailing assumptions and narratives, of their time. In that way, these professionals have contributed to important social movements. They have also deepened–as we too can–the ethical dimensions of professional work.