Environmental fluid mechanics seeks to understand how exchanges of momentum, heat, water, and tracers between the Earth’s surface and the atmosphere influence the structure and evolution of the atmospheric boundary layer and, ultimately, weather and climate. In this talk, I will provide an overview of research at the interface of fluid mechanics, atmospheric science, and environmental engineering, with examples spanning forests, complex terrain, and cities. Topics will include land-atmosphere exchange, turbulence and scalar transport, urban climate, and the role of surface heterogeneity in shaping atmospheric flows. Through these examples, I will highlight how fundamental fluid-mechanical processes connect diverse environmental challenges and motivate the development of measurement networks, theory, and numerical models for understanding and predicting the environment.