Greenhouse Gas and Poison Ivy: Rash Actions Can Become Irritating

|| Science Article |

It appears that we have more than global warming to think of as the amount of greenhouse gases in the atmosphere continues to increase. A recent study showed that the increasing levels of carbon dioxide, a major greenhouse gas, is causing members of the Toxicodendron family of trees, shrubs, and vines to become more toxic. The infamous poison ivy (Toxicodendron radicans) that causes extremely painful skin rashes belongs to this plant genus.   

The research was undertaken by a team from the Marine Biological Laboratory at Woods Hole, Massachusetts. In their setup, the researchers pumped high levels of carbon dioxide (CO2) into three circular areas in a pine forest located in North Carolina. The amount pumped roughly approximated what the CO2 level might be like by 2050. For six years, the team monitored plant growth within the three areas and discovered that aside from growing more abundantly, poison ivy simply became more poisonous.

Previous research has already established that vines were more inclined to grow very fast as a response to an increase in atmospheric CO2, and that different vine species are already increasing all over the planet. This is because vines use the extra CO2 as a building block for more leaves, unlike trees which absorb it to expand their woody parts such as trunks and branches. And, since leaves are the vital plant components in photosynthesis, more leaves to trap sunlight and absorb CO2 mean more growth for the plant. In the case of the poison ivy, this results to a cycle of flourishing. As the poison ivy and most of its ilk from the Toxicodendron family are considered an abomination by campers, hikers, and gardeners, this is far from a good thing. 

But that’s not even the bad part. Poison ivy produces a fatty toxin called urushiol in its leaves. Urushiol already cause agonizing (read: much more than merely painful) skin rashes, but increased levels of CO2 appear to further intensify its potency.

The Marine Biological Laboratory study led by Jacqueline Mohan showed that an increase in amount of the greenhouse gas induced the poison ivy to create a more excruciating version of urishiol. Urishiol is made up of different types of fats. Some of these cause mild irritations, others cause agony. The research team extracted urushiol from the plant leaves and found that the poison ivy pumped with large doses of CO2 produced 150 percent more of the agonizing varieties and 60 percent less of the mild kinds. The team was not certain what caused this  response but proposed that the abundance of carbon dioxide may have triggered chemical reactions that favor the production of the nastier type of urushiol.

Says Jacqueline Mohan, “It'll be more dangerous to go in the forest. . .I have colleagues who are so allergic that their dermatologists tell them they have to change professions."  Aside from poison ivy, other poisonous members of the Toxicodendron (Latin for “poison tree”) family might already be spreading at an alarming rate. Toxicodendrons occur all over the world.