Plants take carbon dioxide (CO2) out of the atmosphere to do photosynthesis, and thus help reduce the greenhouse gases warming the planet. At least, that’s how the story went before researchers from the Carnegie Institution for Science (CIS) realized that the today’s carbon dioxide levels cause the plants to behave in a way that actually contributes to global warming.
Writing in the latest issue of the journal Proceedings of the National Academy of Science, the CIS scientists unveiled new research that shows increased carbon levels cause plants to retain water that otherwise would have evaporated from their leaves, entered theatmosphere and helped cool the planet. At local levels, this effect can increase the temperature to be 25 percent more than what the greenhouse effect would have done on its own.
“There is no longer any doubt that carbon dioxide decreases evaporative cooling by plants and that this decreased cooling adds to global warming,” said Long Cao, a CIS scientist and study coauthor . “This effect would cause significant warming even if carbon dioxide were not a greenhouse gas.”