How does photosynthesis contribute to reducing global warming?

Photosynthesis significantly contributes to reducing global warming primarily by consuming carbon dioxide from the atmosphere. During this process, plants, algae, and some bacteria utilize sunlight to convert carbon dioxide (CO2) and water into glucose and oxygen. By absorbing CO2, a greenhouse gas that traps heat in the Earth's atmosphere, photosynthesis directly helps to mitigate increases in atmospheric CO2 levels associated with global warming.

The reduction of CO2 through photosynthesis is crucial because elevated levels of this greenhouse gas are a major factor contributing to climate change. The more carbon dioxide that photosynthetic organisms can absorb, the less is available in the atmosphere to contribute to the greenhouse effect.

In contrast, other options either do not relate to the mitigation of global warming or do the opposite. For example, increasing atmospheric oxygen levels does not directly reduce global warming; it merely reflects one of the byproducts of photosynthesis. Releasing methane, a potent greenhouse gas, would exacerbate global warming rather than alleviate it, and promoting fossil fuel usage leads to an increase in greenhouse gas emissions, further contributing to climate change.