The study of human impacts on weather and climate continues to be a highinterest topic area, not only among scientists but also the public. Our second edition has continued to build on our funded research studies from the National Science Foundation, the National Aeronautics and Space Administration, the Environmental Protection Agency, the Department of Defense, the National Oceanic and Atmospheric Administration, and the United States Geological Survey. Our numerous research collaborators at the Natural Resource Ecology Laboratory and Civil Engineering at Colorado State University have continued to provide valuable insight on this subject. Over our multidecadal career, the fundamental insights into weather and climate provided by our education at the Pennsylvania State University have become increasingly recognized. We also want to recognize the perspective on these subjects, and science in general, that Robert and Joanne Simpson have provided us in our careers. Their mentorship and philosophy of research, of course, is but one of their many seminal accomplishments.