Quantifying the combined and individual impacts of climate and human activity on the urban green space carbon sink capacity in Beijing

Abstract

Urban green space plays a crucial role in mitigating climate change through enhancing the carbon sink and ecosystem services in urban areas. Understanding how vegetation responds to both climate and human activity in urban areas is essential for effective green space planning. Despite the existence of large-scale studies examining the effects of climate change and human activity on green space, the specific mechanisms driving the Urban Green Space Carbon Sink Capacity (UGCSC) across different urban functional zones remain unclear. The present study used boosted regression trees and structural equation models to investigate the spatiotemporal dynamics of the UGCSC in Beijing from 2000 to 2020 and to assess the relative contributions of climatic factors and human activity to the UGCSC. The findings indicate that the UGCSC increased by 74.2 % of the study area, with 50.7 % of the change driven primarily by human activity, 24.6 % by climate change, and 24.8 % by their combined effects. Key drivers such as elevation, slope, temperature, and Landscape Shape Index showed varying effects across different functional zones. Climatic factors exhibited significant spatial heterogeneity, with temperature being the most influential, contributing 47.2 % to the UGCSC in central urban areas. Conversely, human activity had a dual impact: it reduced UGCSC in densely urbanized zones due to socioeconomic pressures, while landscape connectivity and green space coverage enhanced UGCSC in development and ecological zones. These insights provide a scientific basis for promoting nature-based solutions and guiding sustainable urban planning with the goal of moving toward carbon neutrality.