Citation: Zhu, X. X., Xiong, Z., Wang, Y., Stewart, A. J., Heidler, K., Wang, Y., Yuan, Z., Dujardin, T., Xu, Q., & Shi, Y. (2026). On the foundations of Earth foundation models. Communications Earth & Environment, 7, 103. https://doi.org/10.1038/s43247-025-03127-x Main Takeaways: Current Earth AI Models Are Missing the Point: Researchers have identified eleven features that an ideal Earth foundation model must have — including geolocation awareness, multi-sensor integration, physical consistency, and carbon minimization — yet no existing model comes close to checking all eleven boxes. Most models focus on only one or two features, leaving a major gap between what we have and what we actually need to tackle real-world climate and environmental challenges. The Data Situation Is More Lopsided Than You'd Think: There are now over 1,000 active remote sensing satellites generating nearly 100 petabytes of open satellite data — but labeled datasets used to train AI models account for less than 0.1% of that archive. This massive imbalance is precisely why self-supervised foundation models, which can learn from unlabeled data, are so critical for Earth science going forward. Weather AI Is Already Dramatically More Efficient — But Incomplete: Models like FourCastNet can generate a week-long global weather forecast in under two seconds on a single GPU, using roughly 12,000 times less energy than traditional forecasting systems. Despite this leap in efficiency, major gaps remain: models struggle beyond two-week forecasts, long-term climate projections drift due to incomplete energy balance, and connecting fine-scale satellite imagery with coarse climate models remains largely unsolved. What Comes After the Ideal Model: Once a true Earth foundation model exists, the authors argue the most exciting frontier is using it to build an "Earth Embedding" — a compact, unified representation of our entire planet that researchers worldwide could query without ever touching raw satellite data. Beyond that, challenges like machine unlearning (making models forget sensitive imagery), adversarial defenses, and continual learning as the climate itself changes will define the next generation of Earth AI research.