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March 5, 2014

Climate Change Effects on Allergy


I am an allergist in a small community and I have been invited to be part of a panel on a TV current events program to discuss the effects of climate change on allergy in the community. I am aware of some data on the earlier start and prolonged nature of seasonal pollens. Is there good evidence of other changes we can expect?


By Dr. Leonard Bielory

In the Northern Hemisphere, the balance of evidence strongly suggests that a significant impact of climate change is already discernible in animal and plant populations, as well as communities and ecosystems. Climate changes include advancement of phenological spring events, such as flowering by 6 days and delay of autumn events by 5 days, compared with the early 1960s; climate changes on aeroallergens with increased pollen production from exposure to increased CO2 concentration; increased pollen to local rises in Temp; increased allergenicity in pollen from trees grown at increased Temp; phenological trends toward earlier pollen seasons are associated with local warming over the latter decades of the 1900s that have demonstrated earlier pollination (0.84 days per year) of trees more than grasses or weeds and globally longer pollination seasons.

Personal research that is about to be released also demonstrates a shift in continental U.S. pollen release. First report of signal noted in PNAS report on Ragweed


  1. Ziska, L., K. Knowlton, C. Rogers, D. Dalan, N. Tierney, M. A. Elder, W. Filley, J. Shropshire, L. B. Ford, C. Hedberg, P. Fleetwood, K. T. Hovanky, T. Kavanaugh, G. Fulford, R. F. Vrtis, J. A. Patz, J. Portnoy, F. Coates, L. Bielory and D. Frenz (2011). Recent warming by latitude associated with increased length of ragweed pollen season in central North America. Proc Natl Acad Sci U S A 108(10): 4248-4251.

Leonary Bielory, MD
Professor of Medicine, Pediatrics and Medicine
University of Medicine and Dentistry of New Jersey
Springfield, New Jersey, USA

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