Hermann W. Pfefferkorn is a geologist and paleobotanist who is studying paleoclimate, landscape reconstruction, paleoecology, plant taphonomy, and whole plant reconstruction during the Carboniferous and Permian Periods (359 to 252 million years ago) in China, Peru, North America, and Europe. He is interested in icehouse to greenhouse and greenhouse to icehouse climate transitions and what they can tell us about current and future conditions on Earth. Hermann Pfefferkorn is also interested in questions of mine reclamation, hydrogeology, and the transport of Earth materials. He is now (2020) professor emeritus but active in research.