Water availability surpasses warmth in controlling global vegetation trends in recent decade: revealed by satellite time series

Abstract

A better understanding of the dominant climatic drivers that control vegetation trends across regions and biomes is essential for assessing ecosystem dynamics and land-climate interactions in a warming world. Temperature (TMP) has long been considered as dominant control in global vegetation trends, and growing evidence suggests that water availability plays an increasingly important role in determining trends in vegetation growth over many biomes. However, a detailed spatial-temporal evolution of the vegetation trends and the climatic drivers that effect vegetation trends are not well known. In this study, using a time-varying trend (extracted by the ensemble empirical mode decomposition) of climate and satellite-derived normalized difference vegetation index (as a proxy for vegetation productivity) from 1981 to 2015, we find that the trends in vegetation greening and terrestrial carbon uptake reversed, beginning in the early 2000s, largely driven by the recent drying trend. The relative importance of climatic controls on vegetation productivity trend is estimated using a principal component analysis procedure, and the results demonstrate a global shift in the dominant driver of vegetation trends from TMP to precipitation, and point to intensified water limitation to vegetation growth as warming continues. The findings provide empirical evidence of the spatial-temporal evolution of different climatic drivers behind trends in vegetation productivity.

Keywords

• terrestrial vegetation trends
• time-varying trend
• NDVI
• climatic drivers
• climate change