Ecopath with Ecosim (EwE) is an ecological modeling software that tracks energy flow through food webs using functional groups and relatively few input parameters. It has been in development for 30 years and can model both natural environments and human impacts. The software faces challenges because ecosystems are complex with feedback effects across scales, but the models can still provide useful insights despite uncertainties, especially around climate change and human impacts. The developer thanked the audience and provided his contact information.