New research on the Tibetan Plateau shows that soil temperature and moisture, not just air warming, determine how much carbon alpine ecosystems can store. Using the CLM5.0 land surface model and four decades of observations, scientists found that grasslands have become more productive, with net primary productivity rising each year, but carbon use efficiency has declined. That means more carbon is being fixed, but a larger share is lost to respiration. Soil temperature controls plant growth in spring and autumn, while summer carbon uptake depends mainly on soil moisture. Forests and shrublands respond differently, with moisture more important for woody plants. Because permafrost thaw and changing monsoon patterns are altering both heat and water in the soil, the plateau's future as a carbon sink depends on how these two factors move together.
