How would Earth be different without photosynthesis? Solution Plants,algae and bacteria are the only organisms that can harvest sunlight and use the energy to convert CO2 to organic material.Carbon dioxide is one of the major air pollutants,so photosynthetic organisms are actually keeping the air clean.In the process,they produce oxygen,which constitutes a significant portion of the air we breathe so less plants means less recycling of carbon dioxide and less oxygen production. Plants also give us food and fibers to make clothes and without photosynthesis,we would not be able to sustain the life we are living.If photosynthesis does not occur,most plants would die within short order.Then the animals that temporarily relied on them for sustenance would die..