New research shows that ragweed -- exposed to elevated levels of CO2 -- grows faster than most other plants. Good for ragweed, but not so great for allergy sufferers.
Sue Sweeny/Wikimedia Commons
Almost to the minute of autumn turning this year, my allergies kicked it into high gear. I really shouldn't complain. Portland actually ranked last place out 100 for "The Most Challenging Places to Live with Fall Allergies," according to Asthma and Allergy Foundation of America.
Yet, with my extra sensitivity to the season, two recent news items caught my eye.
University of Virginia biologist Manuel Lerdau has been studying the relationship between ragweed and carbon dioxide. The bottom line: climate change seems to be great for ragweed. As we emit more and more carbon dioxide, ragweed will thrive. And as temperatures warm it could mean longer allergy seasons.
The Daily Progress reports even more than most plants, ragweed loves it some C02:
“Exposed to elevated levels of CO2, ragweed grows faster than most other plants in the eastern U.S., said Manuel Lerdau, a University of Virginia biologist. Also, it appears that CO2 helps ragweed produce chemicals that ward off insects that normally eat the troublemaking weeds, Lerdau said. "We are just going to have more ragweed. It's just going to do better and better in a higher-CO2 world," he said.”
In Conservation Magazine, Rob Dunn looked at research showing that shrinking biodiversity in urban areas may be tied to increase in allergies and other health problems. In his essay, Dunn notes that notions like 'nature-deficit disorder,' or that there's good kind of bacteria, are older ideas to bring about the idea that sometimes 'dirt' can be healthy.
The 2012 study Dunn writes about was led by Ilkka Hanski at the University of Helsinki. Researchers looked at “allergies of adolescents living in houses surrounded by biodiversity to those of adolescents surrounded by simplicity—the modern landscape of cement and grass.” Here’s what Hanski found:
“In retrospect, it seems unlikely that Hanski and his colleagues would find a strong relationship between plant biodiversity, microbes, and allergies… Yet, when Hanski and his colleagues looked at their data, they found a remarkably clear pattern. Higher native-plant diversity appeared to be associated with altered microbial composition on the participants' skin, which led in turn to lower risk of allergies.”
As you sniffle and rub those itchy eyes, you might take a look around. See where the ragweed is getting it’s CO2 fix. And check out how many different kinds of species are in your daily life.
-- Toni Tabora-Roberts
