Arctic ecosystems are changing rapidly due to global warming, making it increasingly important to improve our ability to predict how these environments will respond. The NGEE-Arctic project brings together field observations, process studies, and modeling to better understand key ecological and physical processes in the Arctic, such as permafrost thaw, plant dynamics, and carbon cycling. We’ve used these insights to enhance the E3SM Land Model and simulate how water, energy, and carbon move through Arctic landscapes. To test how well the model performs, we applied a standardized evaluation tool called ILAMB, which compares model results with real-world data across various Arctic sites and scales. We also created new evaluation methods tailored to Arctic-specific processes. Our results highlight where the model performs well and where it needs improvement. This work helps reduce uncertainty in future climate projections and supports the development of more accurate models for Arctic ecosystems.