Quantifying the Relative Contributions of Climate Change and Human Activities to Vegetation Recovery in Shandong Province of China

<p>As global climate change intensifies, with frequent extreme weather events, the stability of vegetation is severely threatened. This study (2002–2023) uses NDVI, temperature, and precipitation data, along with methods like pixel binary, trend analysis, and multiple regression residual analysis, to simulate vegetation coverage changes in Shandong Province and its 16 cities. By comparing potential and actual NDVI, it assesses the benefits provided by climate change and human activities to vegetation recovery. Results show that from 2002 to 2023, Shandong's cities had moderate to high vegetation coverage. Linyi City has the highest, while Tai'an City has the lowest. CC and HA jointly boosted rapid growth of the vegetation NDVI during the growing period (growth rate of 5.36 × 10⁻³·a⁻¹), with 72.1% of the area experiencing significant growth. Within the cities, the fastest NDVI increase was observed in Rizhao (growth rate of 7.22 × 10⁻³·a⁻¹). HA had a substantial positive effect on vegetation recovery in Shandong, while climate change primarily had a moderate positive effect. The relative contribution rates were 73.4% and 21.2%, respectively. In cities such as Liaocheng, Jining, and Zibo, human activities accounted for more than 90% of the contribution, while climate change notably promoted vegetation recovery in Rizhao. NDVI showed a significant decline in areas where climate change exerted slight suppression and human activities had a moderate suppressive effect, particularly in the border areas of Qingdao, Rizhao, Zaozhuang, and some city centres.</p>