Different Satellite Products Revealing Variable Trends in Global Gross Primary Production

Capturing the spatial and temporal dynamics of global gross primary production (GPP) and its underlying mechanisms is important for understanding the global carbon cycle and climate change. Satellite remote sensing enables continuous observation of vegetation dynamics over large regions, providing valuable opportunities for investigating spatial and temporal changes in GPP on a global scale. However, different GPP products typically exhibit significant disparities in terms of global GPP estimations and have different sensitivities to environmental factors due to model differences. Therefore, this study compared five global GPP products to identify the temporal and spatial trends of global GPP in recent years and the sensitivity to environmental factors. Results showed that although the annual mean value of terrestrial GPP exhibited an upward trend over the past three decades, their trends and growth rates on a global scale were not entirely consistent for the periods before and after 2000; they even exhibited opposing trends among different products in tropical regions. Although the spatial pattern of major environmental impact factors for different GPP products was consistent across the globe, some significant differences were observed among the different products. Clarifying the trends of GPP and its response to environmental factors under the current scenario of climate change needs to be further addressed.Plain Language Summary Gross primary production (GPP) represents the growth characteristics and health status of the terrestrial ecosystem and provides the terrestrial ecosystem with the ability to partially offset anthropogenic carbon dioxide emissions. We compared five global GPP products to identify the temporal and spatial trends of global GPP in recent years and the sensitivity to environmental factors. Results showed that the annual mean value of terrestrial GPP exhibited an upward trend over the past three decades, however, trends and growth rates of GPP on a global scale were not entirely consistent for the periods before and after 2000. Furthermore, different products even exhibited opposing trends among different products in tropical regions after 2000. The findings are important for understanding the global carbon cycle and climate change.