CO2 drove changes in global grassland GPP over the past decade

Global climate change has profoundly affected grassland ecosystems. However, the spatial patterns and underlying mechanisms by which environmental drivers influence global grassland gross primary productivity (GPP) remain insufficiently understood. We examined global grassland GPP trends and their associations with eight key environmental variables from 2010 to 2020. Employing ridge regression attribution analysis, we quantified the relative contributions of multiple key factors to interannual GPP variability across global grasslands. To further enhance temporal and methodological robustness, we conducted supplementary analyses for 2003–2020 and an additional XGBoost–SHAP assessment, both of which reinforced the reliability of the main conclusions. Our analysis indicates that GPP increased in 66.44 % of global grassland areas, with 9.19 % of the area exhibiting statistically significant upward trends from 2010 to 2020 Among all factors, atmospheric CO 2 emerged as the dominant contributor, accounting for 44.9 % of the relative impact and contributing an absolute increase of 0.0256 g C m −2 yr −1 . Spatially, CO 2 effects were most pronounced in tropical regions of Africa and South America. Other factors, such as the fraction of photosynthetically active radiation (FPAR) and evapotranspiration (E), exhibited strong positive effects in mid- and high-latitude grasslands. Temperature effects were relatively stable, while wind speed, precipitation, and soil moisture exhibited weaker and more regionally variable influences. These findings highlight pronounced global spatial heterogeneity in the environmental controls on grassland productivity. • Grassland GPP increased globally, with 9.19 % of areas showing significant growth. • CO 2 drove grassland GPP globally, absolute contribution reached 0.0256 g C m −2 yr −1 . • Tropical regions in Africa and South America showed high CO 2 -driven GPP growth. • Clarified spatial mechanisms of environmental impacts on global grassland GPP.