Plants on Earth significantly affect the amount of carbon in the atmosphere primarily through the processes of photosynthesis and respiration. During photosynthesis, plants absorb carbon dioxide (CO2) from the atmosphere and use it along with sunlight and water to produce oxygen and carbohydrates for growth. This process effectively removes CO2, a greenhouse gas, from the air and stores carbon in plant tissues such as leaves, stems, and roots, as well as in soils and ecosystems like forests and grasslands

. This carbon storage helps mitigate climate change by reducing atmospheric CO2 levels. Plants also release CO2 back into the atmosphere through respiration, where they break down sugars to obtain energy. Additionally, when plants die and decompose, carbon stored in their tissues is released into the soil or atmosphere. However, generally, plants store more carbon than they release, making them net carbon sinks

. Rising atmospheric CO2 levels have led to increased photosynthesis, known as the carbon fertilization effect, boosting plant growth and carbon uptake globally. Plants also tend to use water more efficiently under higher CO2 conditions by partially closing stomata, reducing water loss

. However, climate change introduces complexities: warmer temperatures can increase plant respiration rates, potentially releasing more CO2 and reducing the net carbon uptake by vegetation. Some studies suggest plants may allocate more carbon to growth under warmer conditions, partially offsetting respiration losses, but overall, the balance is delicate and influenced by factors like nutrient availability and water stress

. In summary, plants regulate atmospheric carbon by absorbing CO2 during photosynthesis and storing it in biomass and soils, while releasing some CO2 through respiration and decay. Their role as carbon sinks is vital but sensitive to environmental changes that may alter this balance in the future.