Annapolis, MD - In 2006 Duke University researchers published a six-year study showing that when exposed to increased levels of carbon dioxide, poison ivy can grow double in size. They also found that the oil, urushiol, responsible for causing allergic reactions in humans is made stronger due to the increased carbon dioxide. Researchers also recently started looking into the effects that rising soil temperatures may have on poison ivy. Warmer temperatures and increased amounts of carbon dioxide in the atmosphere are all consequences of our changing planet, which will result in thriving, larger amounts of poison ivy and stronger allergic reactions caused from it.