Carbon Gain, Carbon Use, and Persistence: How Elevated CO₂ and Warming Reshape High‐Elevation Plants

frequently increases leaf-level photosynthesis and intrinsic water-use efficiency, while moderate warming can transiently stimulate early-season productivity. However, sink limitation, nutrient imbalance, elevated respiration, and rhizosphere priming constrain structural carbon deployment. Excess assimilates are often diverted to non-structural carbohydrate storage, antioxidant systems, and secondary metabolism rather than durable biomass accumulation. Critically, demographic filters, phenological mismatch, recruitment failure, and stage-specific mortality govern long-term persistence. We argue that persistence, not productivity, ultimately determines alpine carbon stability. Incorporating allocation constraints and demographic processes into ecosystem models is essential for improving projections of mountain carbon-climate feedbacks.