“Climate change creates longer ragweed season”
Ragweed season has begun in the New York/New Jersey metropolitan area with the first sighting by Dr. Bielory, a National Allergy Bureau certified pollen counting station. Three out 4 Americans who have allergies are allergic to ragweed pollen. The earlier sighting appears to be consistent with Dr. Bielory’s report. that climate change may be affecting pollen release and earlier development of allergies.
A changing climate means allergy-causing ragweed pollen has a longer season that extends further north than it did just 16 years ago and in New Jersey appears to increasing in duration of exposure with earlier pollination and longer release days. As part of an ongoing study by Dr. Leonard Bielory and the researchers at Rutgers University and the U.S. Department of Agriculture, funded in part by the U.S. Environmental Protection Agency. According to the study published n the Proceedings of the National Academy of Sciences, allergy experts found that ragweed pollen season lasted as much as 27 days longer in 2009 than it did in 1995 with increasing range northward resulting in a more dramatic the change in the length of pollen season. Allergies associated with ragweed pollen (to which 3 out of 4 Americans who are allergic have ragweed allergies – also known as hay fever) costs about $21 billion a year in the United States. At one time this was hypothesized and modeled as a possibility – “but it is a reality” according to Leonard Bielory, M.D. who is leading the investigation for the U.S. EPA – “this is affecting patients now!” Ragweed is not the only pollen season affected as the study will be evaluating the impact on tree and grass pollen seasons that occur n the early and late spring.
As global average temperatures have warmed, the first frost has been delayed, especially at higher latitudes, which has meant a longer season for ragweed. Because warming is greater at these high latitudes, the length of the season has been more pronounced.
From the report the ragweed season actually shrank by 4 days between 1995 and 2009 in Texas while further north it was noted to be 11 days longer in Nebraska; 16 days longer in Minnesota; and 27 days Saskatchewan in Canada. In New Jersey, the season appears to have increased over the past 20 years, but not as prolonged as the differences noted in Canada. This appears to eventually impact on the diagnosis of allergies that could coincide with the flu season. Primary care physicians may under-diagnose and undertreat allergies since they would not be familiar with such a change in the allergy season and thus may require the assistance of an allergist to confirm the diagnosis to maximize the treatment for their patients.
"Allergies that have been minor in the past are going to increase and become more of a clinical problem that may also impact patients with asthma!” Bielory said.