Climate change is making your seasonal allergies worse. Sigh.

3 min readMar 16, 2021


No, you haven’t been imagining things — allergy season IS actually growing longer and more intense every year. Ominous new research identifies climate change as the primary culprit for this phenomenon and forewarns tough times ahead for the millions of Americans living with hay fever and asthma. [1, 2]

Warmer weather patterns are leading to longer pollen seasons

Findings recently published in Proceedings of the National Academy of Sciences (PNAS) show that pollen seasons in North America have lengthened by 20 days on average since 1990, with pollen concentrations increasing by 21% during the same thirty-year timespan. [3]

Human activity is responsible

This watershed study is the first to definitively demonstrate correlation between human-based climate change and the shifting pollen growing season. Warmer spring temperatures due to increasing carbon concentrations in the earth’s atmosphere are causing the plants, trees and grasses that produce allergenic pollen to begin to do so earlier in the year and for elongated growing seasons. Warmer weather also leads to higher carbon dioxide accumulations in ragweed and other pollen producing plants during the fall, enabling them to yield ever larger pollen quantities.

What does more pollen mean for allergy sufferers?

Because it is a reaction to pollen that triggers the inflammatory immune system response common to seasonal allergies such as allergic rhinitis and which can increase the risk and severity of asthma attacks, longer, more concentrated pollen seasons will undoubtedly spell greater misery for allergy sufferers. In fact, since by some estimates as many as 75% of sufferers are also allergic to common household irritants such as pet dander, dust mites and mold and experience symptoms year round — so-called “perennial rhinitis” — climate change is quickly turning a “seasonal” issue into an “everyday” issue. [4] The researchers of the groundbreaking pollen study warn that the problem can be anticipated to only get worse : “… pollen concentrations are strongly linked to both medication purchases and emergency hospital visits, as well as susceptibility to viral infections through […] weakening immune responses […] we hypothesize that climate-driven changes […] would have important implications for […] allergy and asthma prevalence and associated medical costs” [5]

What can we do about it?

Alongside societal-scaled efforts towards decarbonizing our economy through weaning ourselves from fossil fuels and electrification of our energy usage via adoption of renewable energy sources, there’s plenty we can do as individuals to help mitigate climate change. We can work towards reducing our carbon footprints with everyday, ongoing efforts such as limiting our consumption of methane-producing animals and eating more plant based foods; choosing to bike or use public transportation for most travel and choosing an electric vehicle if we must drive. We can practice sustainability by using more glass and less plastic and by recycling much of what we consume, from paper to electronics. We should engage with and support policy makers on the local and national levels who put forth initiatives to tackle climate change now — while there’s still time to avoid its worst effects.

As sufferers of allergies and asthma, we also should take steps to reduce exposure to the impacts of climate disruption particular to our individual symptomatic triggers. For instance, we should check local pollution levels daily via the CDC’s Air Quality Index. And be sure to visit your immunologist/allergist in order to properly diagnose your condition and to receive a personalized treatment regiment.

Want to learn more? At Cleared we are committed to a #holistic view of climate change — and its solutions. Our telemedicine and our team of allergists are always here to help.

  1. Summary Health Statistics Tables for U.S. Adults: National Health Interview Survey, 2018, tables A-2b, A-2c
  2. Summary Health Statistics Tables for U.S. Children: National Health Interview Survey, 2018, tables C-1b, C-1c
  3. Anderegg et al., “Anthropogenic Climate Change Is Worsening North American Pollen Seasons.”
  5. Anderegg et al., “Anthropogenic Climate Change Is Worsening North American Pollen Seasons.”