Land use change-induced abrupt changes in vegetation and the role of climate factors.

Abstract

Land use change (LUC) and climate are major factors constraining terrestrial ecosystem. As these impacts are expected to intensify in the future, it is necessary to quantify the effects of anthropogenic LUC on the terrestrial biosphere and its interactions with regional climate. Here, we identify abrupt decreases in the Leaf Area Index (LAI) from 2015 to 2100, primarily driven by LUC through cropland expansion. We further examine the role of climate change in the identified LAI reductions. In areas experiencing LUC, a negative relationship between LAI and surface temperature leads to a positive feedback, which reinforces decreasing LAI and increasing warming. Moreover, prolonged regional dry conditions and a shift towards drier climate conditions further exacerbate LAI reductions. These climate change impacts have a large spatial variation and cause western South America to show the most pronounced LAI sensitivity to LUC under the shared socioeconomic pathways (SSP) 3-7.0 scenario. These results highlight the combined effects of LUC and climate change, leading to future abrupt decreases in vegetation cover.