Our worsening seasonal allergies

(Image credit: Illustrated | Gettyimages)

published 27 April 2023

Are your seasonal allergies worse than usual? If your eyes and throat are particularly itchy this year, you're not alone. Research has shown that climate change is making the North American pollen season worse, much to the chagrin of allergy sufferers.

Why is the allergy season worse this year?

Seasonal allergies are usually a result of the body's response to airborne pollutants like pollen and mold which are more prevalent during the blooming season in spring, per The Wall Street Journal. These pollutants come from blooming trees and grasses following the winter. However, this year's mild winter has disrupted the usual seasonal schedule, writes The New York Times. "This winter, since it has been somewhat warm, the trees have been pollinating on the earlier side," Joyce Yu, a pediatric allergist-immunologist, told the Journal.

A 2021 study published in the journal Proceedings of the National Academy of Sciences found that pollen season has increased by approximately 20 days since 1990 and the concentration of pollen in the atmosphere has increased by 21 percent in North America. This pattern is expected to continue because of climate change. By the end of the century, the allergy season could be as much as 40 days longer than in recent decades, according to research published in the journal Nature.

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On top of that, "this time of year, even people who don't have a history of seasonal allergies can be symptomatic," Yu continues. About a quarter of adults and 20 percent of children have officially been diagnosed with seasonal allergies, also known as hay fever, writes the Journal. Symptoms of hay fever include a runny or stuffed nose, itchy eyes, and skin, and sneezing. "Pollen can also trigger an asthma attack, which of course is much more serious for people that suffer from asthma," explained Lauren Casey, a meteorologist with Climate Central, to CNN. Experts warn that the increasing intensity of the allergy season could become a public health emergency in the future.

Trees and other plants use sunlight, rainfall, and temperature to judge when to come out from their dormant positions in the winter and begin blooming, CBS News writes. "They're called 'degree days,' but it's not temperature, it's a heat unit. When that number has been reached, those leaves will push out," explained Val Cervenka of the Minnesota Department of Natural Resources to CBS. "When they get what they need, they'll leaf out and they'll bloom."

Climate change is caused by an increased concentration of greenhouse gases in the atmosphere, which trap and hold heat. Carbon dioxide is one of those gases, and it's released in heavy quantities due to fossil fuel extraction and burning. However, carbon dioxide also serves an important role in pollinating plants by helping them "grow bigger and faster, flower more, and produce more pollen per flower," per the Journal. With more pollen comes worse allergic reactions.

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Devika Rao has worked as a staff writer at The Week since 2022, covering science, the environment, climate and business. She previously worked as a policy associate for a nonprofit organization advocating for environmental action from a business perspective.