Who likes poison ivy? Nobody, right? Actually, Umar Mycka, a horticulturalist at the Philadelphia Zoo, has reason to be growing quite fond of the rash-causing weed. He has started a business removing poison ivy for people who are itching to get rid of it. He is getting plenty of requests, too. A recent study at Duke University shows that rising levels of CO2 in the atmosphere cause the weed to grow more vigorously, and they may eventually cause a more toxic form of poison ivy resin to be formed. Even now, an acute case can require steroids or hospitalization. Most people who contract the rash simply did not look out for poison ivy. Keep an eye on what you are touching and wear appropriate clothing if you’re going to be out in weeds or the woods.