Asynchronous Changes in Vegetation Greenness and Climate Variables Isolines During 1986–2020 Over the Tibetan Plateau

Abstract

Vegetation greenness on the Tibetan Plateau has benefited from climate-driven temperature and precipitation changes over the past decades. Whether and to what extent the horizontal and vertical shifts of vegetation isolines keep pace with the temperature and precipitation isolines, as well as hidden mechanisms remain elusive. Analyzing the greenness and climate data over 1986–2020, our study reveals widespread mismatch, with 76.9% (87.1%) of horizontal greenness isolines lagged or diverged from temperature (precipitation) isolines. Similarly, 55.8% (77.9%) of vertical isolines showed lagging or diverging patterns relative to temperature (precipitation) isolines. Horizontal shifts in vegetation isolines were influenced by slope, precipitation and grazing intensity; while their vertical shifts were primarily driven by water-related factors that mitigate warming effects. The drivers responsible for asynchronous responses provide predictive understandings of alpine vegetation dynamics under a changing climate.