What natural process removes carbon dioxide from the atmosphere through plant growth?

Photosynthesis is the natural process by which plants remove carbon dioxide from the atmosphere as they grow. Using light energy, plants convert carbon dioxide and water into sugars, releasing oxygen as a by-product. The overall process is commonly summarized as 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.

Most photosynthesis takes place in chloroplasts, especially in leaf cells. Chlorophyll absorbs sunlight during the light-dependent reactions, producing chemical energy. The Calvin cycle then uses that energy to fix carbon dioxide into organic molecules, which the plant can build into sugars, cellulose, starch, and other compounds. Some of this carbon remains stored in vegetation, roots, soils, or wood for varying lengths of time.

Photosynthesis is not the same as plant respiration. Plants respire continuously, using sugars and releasing some carbon dioxide, while decomposition also returns carbon to the atmosphere as organisms break down dead material. Combustion releases carbon dioxide rapidly. Photosynthesis is therefore the key biological carbon-uptake process, although ecosystems do not permanently remove all the carbon they absorb.