If you suffer from seasonal ragweed allergies, you may have noticed that your allergy symptoms are lasting longer each year, especially if you live within the northern climates of the U.S. and into Canada. According to a new study, your imagination is not the culprit, but a change in climate that’s extending your season of misery. The findings of the study were recently published in the online issue of the Proceedings of the National Academy of Sciences.
The new research suggests that ragweed season has grown longer by more than two weeks for people who reside in areas of the northern U.S., while for those who live in certain areas of Canada, the suffering season has been extended by almost a full month. According to the study background information, ragweed pollen sensitivity is very common among U.S. allergy sufferers, with at least one in ten Americans being affected. In fact, about 27 percent of Americans who suffer from allergies are sensitive to ragweed.
Lewis Ziska, a plant physiologist with the U.S. Department of Agriculture’s crop system and global change laboratory, and his colleagues set out to discover why there has been a continuous increase in allergic disease occuring within the U.S. over the past three decades. Experts have theorized that the increase is due to an extended exposure to allergens linked to longer pollen seasons caused by global climate changes.
The research team analyzed data from both the U.S. and Canada regarding ragweed and daily temperatures. Their findings showed that between 1995 and 2009, the number of days in the ragweed pollen season increased in eight of the 10 latitudes examined, including all seven of those analyzed that were north of 40 degrees latitude. The length of the season increased as the location moved further north, with the exception of the Oklahoma City area.
Results of the study showed that in Canada, Winnipeg had 25 days longer of misery for allergy sufferers, and in Saskatoon, it was 27 days longer. Northernmost areas of the U.S. examined included Minneapolis, Minnesota and Fargo, North Dakota found to have a 13-day extension of ragweed season, while LaCrosse, Wisconsin had an additional 13 days, and Madison, Wisconsin had an additional 12 days, followed closely by Papillion, Nebraska having 11 additional days. Southernmost areas studied showed an actual 3-day decrease in the allergy season for Rogers, Arkansas, and a 4-day decrease in Georgetown, Texas, while Oklahoma City had only a 1-day decrease.
Regarding the outcome of the analysis, Ziska acknowledged, “This study is a confirmation of what the Intergovernmental Panel on Climate Change has been projecting. We’ve gone from a theoretical projection of changes in the timing of ragweed season, to boots on the ground starting to see it happen.” He then warned, “This is a caution light. Pollen seasons may be getting longer, and climate change may have health implications as well.”