"Carbon fertilization" refers to the phenomenon where higher concentrations of carbon dioxide (CO2) in the atmosphere promote increased photosynthesis in plants, leading to enhanced growth and productivity. This effect is particularly pronounced in C3 plants, which make up a significant portion of global vegetation. In the context of UPSC Prelims, understanding carbon fertilization is crucial as it highlights the complex interactions between climate change and agriculture, emphasizing the potential benefits and challenges posed by increased atmospheric CO2 levels on food security and ecosystem dynamics.