Changing weather patterns create longer seasons and more pollen
The past decade was the hottest ever recorded, with 2019 as the second warmest year on record. This warming is expected to continue for the foreseeable future as carbon dioxide emissions and other greenhouse gases are continually released into the atmosphere, largely from the burning of fossil fuels.
As global temperatures rise and weather patterns change, increased levels and duration of airborne pollen and pollution occur. This prolongs allergy suffering for more than 50 million Americans each year.
According to Dr. Lewis Ziska, Associate Professor at Columbia University Mailman School of Public Health, there are three key factors happening now that contribute to worsening allergies:
- Climate change is extending the frost-free season, giving trees and plants more time to grow, flower, and pollinate. (Primary allergens come from trees in the spring, weeds and grasses in the summer, and ragweed in the fall.)
- Warmer temperatures generate higher amounts of pollen from these plants. (In a study by the Asthma and Allergy Foundation of America (AAFA), spring arriving 30 days earlier resulted in a 54.8% increase in ragweed pollen production.)
- Plants need carbon dioxide to thrive, and as carbon dioxide levels rise in our atmosphere, initial evidence suggests that it may change the structure of pollen in plants like ragweed and certain trees, making them more allergenic.
Pollen counts are increasing over time
In a study conducted by the American College of Allergy, Asthma and Immunology (ACAAI), pollen counts are expected to more than double by the year 2040.
As a result, allergies have become much more pervasive among Americans over the past few decades. In 1970, 1 in 10 Americans suffered from allergic rhinitis caused by pollen and mold spores. By 2000, 3 in 10 did, and the trend continues today.
Climate change is making more people allergic
The overall impact of worsening allergy cases has become expensive and damaging. Some key facts from the Asthma and Allergy Foundation of America (AAFA):