Plants May Contribute to Global Warming
Although photosynthesis allows plants to absorb CO2 from the air and exhale oxygen, there are some unexpected side effects with increased CO2 levels that may make plants contribute to global warming. Recent research at the Carnegie Institution for Science (CIS) has determined that as a result of the increased carbon dioxide (CO2) in our atmosphere, plants are actually retaining water that normally would evaporate from their leaves, consequently causing a local temperature increase up to 25 percent over the normal greenhouse effect.
According to a report in the Proceedings of the National Academy of Sciences, scientist Long Cao explained, "There is no longer any doubt that carbon dioxide decreases evaporative cooling by plants and that this decreased cooling adds to global warming. This effect would cause significant warming even if carbon dioxide were not a greenhouse gas.” The small vents in plant leaves, called stomata, do not need to open as wide to breathe in the CO2, so they close up, which prevents water from escaping. This effect is not included in current climate models, and could well complicate attempts to reverse the effects of global warming.