In this chapter we describe current and future solutions to providing representations of the natural environment to modeling and simulation (M&S) architectures. Two recently developed applications we describe are the Ocean, Atmospheric, and Space Environmental Services (OASES) federate and the Acoustic Transmission Loss Server (ATLoS) federate. These applications, working in concert with the Navy’s Tactical Environmental Data Services, TEDServices, exemplify the current practice of distributing environmental data services to Navy M&S. Our experience with developing and using these applications within the current M&S interoperability framework, the High Level Architecture and Run-Time Interface (HLA/RTI), have led us to begin to develop a newer representation scheme for environmental models: an ontology of physics. An ontology of physics provides a more abstract semantic description scheme for representing both models of the natural environment and their data. Nothing less than a full ontology of physics will do to represent semantic information because Department of Defense (DoD) systems that are operationally sensitive to environmental conditions are in space, the atmosphere, and the ocean and require representation of fluid dynamics, thermodynamics, electrodynamics, quantum mechanics, and even general relativity.