Confronting Grand Challenges in environmental fluid mechanics

Environmental fluid mechanics underlies a wealth of natural, industrial, and, by extension, societal challenges. As we strive toward a more sustainable planet, there is a wide range of problems to be tackled, from fundamental advances in understanding and modeling of stratified turbulence and consequent mixing to applied studies of pollution transport in the ocean, atmosphere, and urban environments. The discussions and outcomes of a recent Les Houches School of Physics meeting are summarized here with the intent of providing a resource for the community going forward and a plan of action for the coming decade.