The article discusses the global net primary production (NPP) and its estimation using a combination of ecological principles and remote sensing data. NPP is the net amount of carbon fixed by plants through photosynthesis, and it is a key indicator of the carbon cycle. The study highlights the challenges in estimating NPP globally, including the need for accurate data on climate, soil, and plant characteristics. The CASA model, introduced by Potter et al. (1993), is presented as a method that integrates ecological principles with satellite data to estimate NPP on a monthly time step. The model calculates NPP as the product of absorbed photosynthetically active radiation (APAR) and an efficiency of radiation use (ε). The CASA model estimates annual terrestrial NPP to be 48 Pg and the maximum efficiency of PAR utilization (ε*) to be 0.39 g C MJ⁻¹ PAR. The model accounts for spatial and temporal variations in APAR and ε, and it uses satellite data to estimate these variables. The study also discusses the limitations of the model and the challenges in estimating NPP globally, including the need for more accurate data on climate, soil, and plant characteristics. The article concludes that the CASA model provides a useful tool for estimating NPP globally, but further research is needed to improve the accuracy of these estimates.The article discusses the global net primary production (NPP) and its estimation using a combination of ecological principles and remote sensing data. NPP is the net amount of carbon fixed by plants through photosynthesis, and it is a key indicator of the carbon cycle. The study highlights the challenges in estimating NPP globally, including the need for accurate data on climate, soil, and plant characteristics. The CASA model, introduced by Potter et al. (1993), is presented as a method that integrates ecological principles with satellite data to estimate NPP on a monthly time step. The model calculates NPP as the product of absorbed photosynthetically active radiation (APAR) and an efficiency of radiation use (ε). The CASA model estimates annual terrestrial NPP to be 48 Pg and the maximum efficiency of PAR utilization (ε*) to be 0.39 g C MJ⁻¹ PAR. The model accounts for spatial and temporal variations in APAR and ε, and it uses satellite data to estimate these variables. The study also discusses the limitations of the model and the challenges in estimating NPP globally, including the need for more accurate data on climate, soil, and plant characteristics. The article concludes that the CASA model provides a useful tool for estimating NPP globally, but further research is needed to improve the accuracy of these estimates.