Don’t Blame Pollen for your Worsening Allergies—Blame Climate Change!

One weekend, I took a walk around my neighborhood in search of fresh air. I had just left my driveway when I noticed hazy dust raining down on me. Was it misting? No, my hair was dry. As the chalky powder hit my skin, I came to an astonishing conclusion–the mysterious dust was actually pollen. 

Within the last decades, pollen concentrations have steadily risen, and (as you might guess) the main culprit is climate change. As surface temperatures increase, pollen seasons lengthen and intensify, posing serious health concerns.

Climate Change’s Role

Now, you might be thinking: Does this actually affect me? Put simply–yes, this is relevant to you. A recent study published in the Proceedings of the National Academy of Sciences (PNAS) examined the correlation between climate change and North American pollen, specifically how long pollen seasons last and how much pollen is being produced. 

Alarmingly, the scientists–using long-term pollen data from 60 North American cities–found about a 20% increase in the annual pollen count and around a 20-day earlier start for pollen seasons between 1990 and 2018.

These results were then applied to model selection analysis to identify which climate factor best explains four crucial pollen metrics—annual count, spring count, start date, and season length. In simpler terms, imagine the scientists wanted to win four separate car races while only using one race car. They would weigh the strengths and weaknesses of each car and then use that data to make a selection. In this case, the scientists used the Akaike Information Criterion, a program that calculates how well a model fits its dataset compared to other model options. The scientists found that mean annual temperature best predicts the four pollen metrics. 

So, how does this relate to climate change? To answer that, the scientists applied mean annual temperature and pollen data to 22 Earth system models. As the name suggests, Earth system models are simulations that scientists use to understand the expanse of climate change alongside biological, chemical, and geological factors. They found that climate change contributes strongly (45-84%) to earlier pollen seasons and slightly (6.5%) to annual pollen concentrations.

Of course, if these alarming statistics ring warning bells, remain calm; climate change’s effects are happening at unequal rates in North America. I spoke to one of the authors of the PNAS study–Dr. Lewis Ziska, an associate professor of Environmental Health Sciences at the Mailman School of Public Health at Columbia University–about this phenomenon. Regarding “the change in pollen, we’re seeing bigger effects with temperature, but the relative rate of increase in temperature is greater for these northern climates,” he said. He went on to clarify that humid environments already have a prominent greenhouse gas–water. So, when you add carbon dioxide, it will only increase the heat slightly, whereas carbon dioxide will induce more serious heating in the arid North. But how does this affect pollen? As the study indicates, elevated temperatures correlate with a worsening pollen season.

Impact on Allergies

So depending on where you live in the United States, whether in the frigid northern regions or the warmer coastal cities, there is one unanimous idea: Climate change is affecting your health. For allergy sufferers, this news is particularly frightening. A 2021 data brief from the National Center for Health Statistics (NCHS) shows that 21.1% of surveyed men and 29.9% of women have seasonal allergies. And, even if you aren’t diagnosed with seasonal allergies, someone you know may have them. 

What’s next?

If you have severe reactions to seasonal allergies (or they leave you feeling groggy for longer), allergy immunology research could help. Scientists are developing a method of giving patients small doses of allergens–either orally or through injection–to slowly build up resistance to their allergy. According to a study in the Frontiers of Allergy, around 70% of patients have experienced positive results for up to three years after the treatment stops. However, a small number of patients with food allergies developed anaphylaxis–a severe, potentially life-threatening, allergic reaction–after their first dose. Ongoing research is attempting to unlock the mechanisms behind allergen desensitization and negative reactions to treatments.

As Dr. Ziska explained, “I’ve been doing this for 30 years, so the attitudes and the feedback that I’ve gotten from folks about climate change is very, very different than when I first started.” From hoax claims to ignorance, we have grown into generations willing to take on the burden of climate change and fight for a better future, one free of looming allergy seasons.