Life

Adjustment of the Earth’s climate

Vegetation strongly affects the Earth’s climate and the composition of the atmosphere through the photosynthesis activity. Through this process, plants absorb carbon dioxide (CO2) from the atmosphere, trap carbon (C) to build organic molecules and release oxygen (O). Due to the extension of vegetation on Earth, the amounts of oxygen and carbon dioxide that get into this process are huge: every year, the plants’ photosynthesis releases approximately 70 billion tons of oxygen and consumes an equally huge amount of carbon dioxide. Through the photosynthesis, plants counteract the many oxidation processes (for instance, combustion for the production of energy, as is in all the bodies of the living beings, or combustion in industrial processes and car engines), that, using the oxygen contained in the air and giving back carbon dioxide, cause the concentration of the former in the atmosphere to decrease and that of the latter to increase. In this way, plants play an essential role for life on Earth: stabilising the gas composition of the atmosphere. In addition, the stabilisation of the composition remarkably affects the atmospheric temperature and humidity; this subject will be dealt in more detail in the Section on “AIR”.