Joint Effects of Climate and Phenology on Agricultural and Ecological Resource Productivity

Gross primary productivity (GPP) serves as a critical indicator of carbon uptake in agricultural and natural ecosystems, quantifying the extent of carbon dioxide fixation through photosynthesis. Understanding the influence of climate, phenology, and elevation on GPP is essential for achieving carbon neutrality and ensuring sustainable agricultural and ecosystem management. This study adopts a novel methodology that integrates the Shapley Additive Explanations analysis framework with the XGBoost model (R 4.3.3 package xgboost 1.7.7.1) to elucidate complex nonlinear interactions among the factors under investigation. The results show that from 2001 to 2022, GPP increased at an average rate of 6.77 g C/m2/year, with forests exhibiting the highest productivity (>900 g C/m2) compared to grasslands and croplands (300–600 g C/m2). Phenological changes, such as a 0.44 d/year extension in the growing season and a 0.20 d/year advancement in its peak, highlight the significant impact of climate change on vegetation growth. SHAP analysis further identifies precipitation as the primary driver for croplands, growing season length for forests, and temperature for grasslands. These findings support global initiatives aimed at achieving sustainable development goal 13 (Climate Action) by offering actionable insights for adaptive land use policies and carbon-neutrality strategies.