Allergy season in the U.S. is getting worse due to the consequences of climate change. This emerging pattern was revealed in a new Climate Central report titled “Seasonal Allergies: Pollen and Mold,” which was carried out for the climate research nonprofit by researchers from the Columbia University Irving Medical Centre, the University of Nebraska Medical Centre, and Emory University.
How can climate change influence allergy season?
Angiosperms, such as ragweeds, reproduce through the dispersion of pollen, a fine powdery substance, in a process called pollination. Pollen is an airborne allergen causing the allergies commonly referred to as “hay fever.” According to the US Centers for Disease Control and Prevention, about a quarter of adults in the United States suffer from seasonal allergies.
Plants’ biological rhythms, including their blooming season, are influenced by temperature, which, in turn, is affected by climate change. A 2022 study by researchers from the University of Cambridge and Johannes Gutenberg University published in 2022 by the Royal Society found that in the UK, the community-wide mean first flowering day is coming earlier by a month compared to the mid-80s. The rising temperatures resulting from anthropogenic global warming have been leading to the allergy season starting earlier and getting longer.
The research
Scientists have abundantly investigated the relationship between health and climate change as a whole. The effect of climate change on allergies specifically has been the subject of a growing body of literature. A 2021 study titled “Anthropogenic climate change is worsening North American pollen seasons,” published by the Proceedings of the National Academy of Sciences (PNAS), found that in the US, compared to 1990, pollen season lasts longer and starts earlier while nationwide pollen amounts rose.
“The strong link between warmer weather and pollen seasons provides a crystal-clear example of how climate change is already affecting people’s health across the US. Climate change is already here in every spring breath we take and increasing human misery,” says William Anderegg, the study’s first author in a statement. “The biggest question is—are we up to the challenge of tackling it?” Lewis Ziska, senior author of the study, reiterated that “we still hear about climate change impacts as something in the future, but this study shows that it is already occurring, and there will be health consequences, especially for allergy sufferers.”
Climate Central analyzed temperature data for 203 cities dating back to 1970 to look into how the length and severity of allergy season are being impacted by climate change and warmer temperatures in the United States. The scientists observed that the freeze-free season is expanding across the United States, offering plants more than two weeks longer on average to grow, blossom, and discharge pollen.
85 per cent of the US cities looked at in the study experienced a lengthening of their freeze-free seasons over the research period. The time between the last and the first freeze grew by at least a month in 31 cities. This season in Reno, Nevada, was extended by 99 days, one of the most considerable extensions in the nation.
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