We present work done within the Grid ENabled Integrated Earth system model (GENIE) project to take the original, complex, tightly-coupled Fortran earth modeling ap- plication that has been developed by the GENIE team and enable it for execution within a component-based execution environment. Further we have aimed to show that by repre- senting the application as a set of high-level Java Web Service components, execution and management of the application can be made much more flexible. We show how the applica- tion has been built into higher-level components and how these have been wrapped within the Java Web Service abstraction. We then look at how these components can be composed into workflows and executed within a Grid environment.