Impact of compound drought and heat extremes on terrestrial ecosystems

Compound drought and heat extremes (CDHE) are expected to intensify and become more frequent as the climate warms, yet their consequences for forest growth and ecosystem stability remain incompletely understood. Here, we combine long-term tree-ring observations with satellite remote sensing to quantify how CDHE influence tree growth and ecosystem resilience across contrasting climate regimes. We find that increasing CDHE frequency leads to widespread growth reductions across most regions, with the exception of cold and humid ecosystems. Growth declines are particularly pronounced in warm–dry, warm–humid, and cold–dry regions. Notably, tree growth in humid ecosystems exhibits increasing sensitivity to CDHE, indicating that these systems may experience disproportionately large growth losses under compound extremes. In parallel, ecosystem resilience declines with rising drought frequency, with the strongest reductions observed in dryland regions. Together, these results suggest that the intensification of compound drought and heat extremes poses growing risks to forest productivity and stability under continued climate warming.