Global warming = super-allergies? U.S.Dept of Ag thinks so.

Wednesday’s Wall Street Journal reports on scientific studies suggesting strongly that the increase of carbon dioxide in the atmosphere results in hardier, larger, and more potent allergens from allergy-inducing vegetation. For the 35 million people in the U.S. that suffer nasal allergies, none of this is good news.

Giant Ragweed

Dr. Lewis Ziska of the U.S. Department of Agriculture, interviewed for the article, has conducted studies that have revealed that most likely due to the warmer temperatures and 20% higher concentration of carbon dioxide in urban areas, the same pollen-producing plants produce five times the pollen of otherwise identical plants grown in rural areas. Dr. Ziska’s studies under controlled circumstances bore these more general studies out: cultivating ragweed under varying controlled amounts of carbon dioxide concentrations produced increasingly larger and more prolific pollen as the carbon dioxide concentration was increased. His field studies found that urban ragweed plants in Baltimore produced humongous ragweed plants, 190% larger than the rural ragweed plants 40 miles outside the city, and the pollen production followed size closely.

Among the changes occurring:

  • Peak season for allergens from vegetation has been arriving 10-15 days earlier over the past 30 years, a trend expected to continue. (source: August ’07 report from the International Panel on Climate Change)
    • Pollen season in Europe for birch, a major hay fever producer, has arrived 5 days earlier per decade over the past 30 years
  • Ragweed, which was next to completely absent in Europe 10 years ago, is now prevalent in Hungary, France, Italy, the Netherlands, and Scandinavia.
  • In 2004, asthma affected more than 6% of the U.S. population, compared to 3% in 1980 (source: U.S. Centers for Disease Control and Prevention in Atlanta (CDC))
  • Childhood asthma jumped to 9% of children in 2005, versus 3.6% in 1980 (source: CDC)
    • Inner city youth asthma linked to higher city/urban carbon dioxide concentrations which produce increased plant pollen, fungal growth, and opportunistic weeds (source: 2004 Harvard Medical School Study)
    • Pre-school asthma rates grew 160% between 1980 and 1994, more than double the general U.S. population’s asthma rate of increase (source: Ibid.)

What’s bad news for allergy sufferers is bad news for me.

But count me on a team with growing ranks. Anecdotal evidence of the increased potency these allergens carry I’ve found during the past two weeks: pollen counts have been in the thousands, extraordinarily high, and I have both one relative and one co-worker who, now in their thirties and never having suffered nasal allergies before, have been “taken down” by the recent pollen onslaught, and definitively so: fearing illness both visited the doctor, and both were told, to their amazement, “it’s allergies. Deal.”

So misery loves company, but let’s hope we all have the wherewithal to do something about it.



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Filed under Environment, Health, Personal

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