evidence: Reducing the amount of carbon in the atmosphere is an important step if we are aiming to reverse global warming. Nature has an elegant solution. Plants take in water and carbon dioxide from the atmosphere and -- through photosynthesis -- convert it into oxygen and organic compounds. Could we mimic nature and pull carbon from the air? [...] But that doesn't address more than half of the carbon dioxide we humans produce. We produce more carbon dioxide from our homes, vehicles and businesses than we do from factories or wells [source: Prakash, et al.]. But because we don't produce carbon dioxide in a steady stream, like some point sources do, it's harder to capture. The carbon dioxide concentration in the atmosphere is about 385 parts per million -- it's so diffuse that it's difficult to capture.