You’re Not Imagining It: Your Allergies Are Getting Worse
The fresh scents and joy of spring flowers can be a source of torture for many, for whom their arrival is signaled by sneezing, sore throat and itchy eyes. And they’re all just on the horizon.
Dangerous allergy seasons have been on the rise over the past decades due to climate change. More carbon in the air is lengthening allergy season and exacerbating allergies. That’s bad news for the nearly one-quarter of American adults and one-fifth of the nation’s children who suffer from seasonal allergies—and it’s especially extreme in some areas of the country.
In a new report from the nonprofit Climate Central, researchers studied temperature data from 203 US cities from 1990 to 2018, finding that more carbon dioxide in the atmosphere is increasing the duration of seasonal allergies. Winters are getting warmer, and spring is coming more quickly; According to the EPA, the last frost of the year in the spring is occurring earlier than at any time since 1895.
The report found that 85% of US cities had longer spring and summer weather – meaning plants are leafing and blooming earlier, extending the pollen season by an average of 20 days across the US.
For example, it’s extending the seasonality of ragweed, a weed that’s part of the daisy family and the biggest culprit of fall allergies; One plant produces one billion pollen grains, which can spread hundreds of miles from the source. In parts of the Midwest, ragweed season now begins as early as August and runs through October—about three weeks longer than before.
Reno, Nevada has the longest pollen season: 99 days longer in 2018 than in 1990. Louise Ziska, one of the researchers and an associate professor in environmental health sciences at Columbia University, points out that high-elevation places like Reno now have hotter days than ever before, so pollen is living longer.
Not only is the season heating up, but the intensity of allergies is also on the rise. More carbon dioxide allows plants to flourish through photosynthesis, so they produce more energy to grow and increase in numbers – and produce more pollen as a result. Over the same time period, pollen concentrations have increased by 21%.
And pollen isn’t the only trigger. Many people are also sensitive to various fungi that spread from July through the fall. Growing on rotting logs and fallen leaves, the spores of the fungus are released into the air and cause allergies similar to pollen. In warm and wet conditions—including areas with increased tropical storm activity—more spores are produced and they are able to travel faster.
For example, a city like Dallas, which ranked second in the Worst US Cities for Allergies 2023 report, has all the triggers seasonal allergies. It has pollen-producing trees in spring, and grasses and molds in summer, all of which are widely spread due to the warm and humid weather. In the fall, there is ragweed, which can last for months. And in winter: “cedar fever,” a nickname for pollen from mountain pine trees, which are indigenous to Texas and have the largest pollen counts in the state.
These heightened allergies mean sufferers feel all the familiar symptoms including sneezing and itching. But the health effects may be more pronounced for people with asthma or respiratory problems, which can lead to increased pollen and mold. Who himself has severe asthma. “When I’m outside, especially in the spring,” he says, “I always have to carry my inhaler with me to make sure I don’t go into a full-blown asthma attack.”
This trend could get worse if carbon levels remain high in the future. Another study modeling future pollen production predicted it could double by the end of this century, and that the season could start up to 40 days earlier.