Get Ready to Itch and Sneeze

City dwellers who suffer from asthma already are being hit by a "nasty synergy" of hotter temperatures, smog and increasing pollen counts, says Paul Epstein of Harvard's Center for Health and Global Environment. A large percentage of asthmatics are also allergic to pollen. These patients suffer from a double whammy of pollen and smog on days when ground-level ozone levels are high.

Country folk face new challenges, too. Poison ivy, a woodland plant that causes itching and a weepy rash, is becoming more toxic. Researchers at Duke University stumbled across this discovery while conducting an experiment that involved pumping extra carbon dioxide into a plot of pine trees to see whether the forest would soak up and sequester more carbon, mitigating climate change. But they noticed that poison ivy on the forest floor proliferated. Subsequent testing showed that the poison ivy's rash-causing oil, urushiol, was more potent than normal.

Climate change could also spell trouble for people allergic to stinging insects. Alaska, which is warming faster than the rest of the country, could be a test case. In some areas, reports of severe stings from Hymenoptera—the insect order that includes bees, wasps and yellow jackets—are up 600 percent in eight years. Jeffrey Demain, an allergist with the Allergy, Asthma and Immunology Center of Alaska, says yellow jackets and wasps are showing up in places they never lived before.

Skeptics sometimes cite increased crop yields and more-prolific plant growth as reasons to be unconcerned about global warming. But if Ziska and his cohorts are right, the coming global greenhouse will be a sneezier, wheezier and rashier place—and many more people may be whiffing from inhalers.

© 2008