Spatial variability of ecological shifts in lakes in response to anthropogenic activities and climate change over the past two centuries

Abstract Over the past two centuries, anthropogenic stress and climate change have blurred understanding of their individual and combined impacts on lake ecosystems. This study analyzed 477 ecological shifts documented in 224 paleolimnological records from lakes to trace their responses to climate change and anthropogenic stressors over time. By classifying ecological shifts according to their primary drivers (anthropogenic stress, climatic change, or their combined effects), this study characterized how lake ecosystems respond to these pressures. Stress response analysis revealed that climate‐driven responses predominated during post‐Little Ice Age warming, whereas anthropogenic stress became the dominant factor by the early 20 th century, accompanied by the onset of the 2 nd Industrial Revolution. While the Great Acceleration initiated widespread ecological shifts in lakes globally through synergistic interactions between anthropogenic activities and climate change, anthropogenic stress may still exert a greater impact on these shifts than climate change. Spatial analysis revealed divergent responses across lake ecosystems across the globe, though representation was limited from the Southern Hemisphere and tropical regions. Temperate lakes are highly susceptible to anthropogenic stressors; Arctic lakes have heightened sensitivity to climate change; and alpine lakes have coupled responses to both drivers. The cumulative response index developed in this study isolates individual stressors temporally, revealing substantial impacts of historical human development on lake ecosystems. These effects leave persistent signatures preserved in sedimentary archives, providing new perspectives on drivers of ecological trajectories across temporal scales.