Temperature and Precipitation Associations with NDVI on the Qinghai–Tibet Plateau: A Systematic Review and Multilevel Meta-Analysis

Normalized Difference Vegetation Index (NDVI) dynamics on the Qinghai–Tibet Plateau are widely examined, yet published studies report spatially and methodologically heterogeneous relationships with temperature and precipitation. This study synthesized correlation-based evidence through a systematic review and multilevel meta-analysis. The Web of Science Core Collection search identified 597 records: one duplicate was removed, 596 unique records were screened, and 107 articles underwent full-text assessment. The main synthesis included 84 effects from 11 studies. After CR2 robust variance correction, pooled correlations were 0.371 for temperature (95% CI: 0.049–0.623; p = 0.029) and 0.394 for precipitation (95% CI: 0.119–0.613; p = 0.0138), with no reliable difference between drivers (p = 0.526). Positive directions persisted under assumed within-study sampling correlations and conservative effective sample size assumptions. When all monthly scale effects were excluded, pooled estimates remained positive, but confidence intervals crossed zero, indicating reduced precision and dependence on temporal resolution. The findings therefore support positive average NDVI associations with both climatic drivers but not spatially or temporally uniform responses.