Increased ecohydrological drying over terrestrial ecosystems

The greening and browning of global vegetation are driven by various processes such as climate change, CO₂ fertilization, and land management, etc. From the perspective of the vegetation-water-heat relationship, the above processes can be briefly summarized as two types of eco-hydrological processes: 1. dryness change; 2. usage change. We here present a diagnostic procedure to identify the dominant eco-hydrological processes, thus evaluate the climate change impacts on ecosystems. Utilizing remote-sensing based leaf area index (LAI) and climate data during 1982–2016, we demonstrate that dryness changes showed prior dominance over 1/4 global lands where LAI trends are significant. Concretely, drying/wetting has expanded/reduced its regional dominance from 8%/15.8% (1982–1999) to 18.1%/11.9% (1999–2016), indicating that dryness change has turned to more drying than wetting for global vegetated lands. As increased over twofold, drying is playing an increasingly important role in the climate change impacts on terrestrial ecosystems, bringing fundamental weakening of global greening.