An Itchy Problem—More CO2 May Produce More Poison Ivy

September 01, 2010

“It started with a slightly puffy eyelid in early summer… The next morning, I couldn’t ignore my son’s symptoms when he appeared with two eyes swollen to slits, a bloated face and an itchy rash raging over his body.” Laura Hambleton, writing in The Washington Post, notes that carbon dioxide—the levels of which have increased in our atmosphere by over 20 percent since 1960—may be feeding an increase in poison ivy. Jacqueline Mohan, an assistant professor at the University of Georgia’s Odum School of Ecology, has been tracking poison ivy since 1998. “Tree seedlings grew 8 to 12 percent more, with more C02,” Mohan says. “Poison ivy grew 149 percent more. Poison ivy is getting bigger, faster and nastier.” Mohan observes, “Vines are particularly adapted to take advantage of higher CO2 in the atmosphere,” as they “can increase their rate of photosynthesis to make more green leafy tissue.” By contrast, trees have to devote more energy “to creating woody, non-photosynthetic support tissues such as trunks and branches, which do not lead to further increases in photosynthesis.” You may also be delighted that pests like ticks and bark beetles are on the rise from warmer temperatures. Check out this earlier blog posting.