Climate change is making allergies worse

By | May 6, 2023

Every spring many allergies They appear with the same consistency, but the symptoms for many seem to be getting worse, and climate change is probably to blame.

“Allergy seasons are getting longer and more intense,” says Kenneth Mendez, executive director of the Asthma and Allergy Foundation USA. Plants produce more pollen over a longer period of time, and the problem isn’t just that warmer temperatures lengthen the plant’s growing season. Carbon dioxide itself favors the production of pollen.

Compared to thirty years ago, North American pollen season now starts twenty days earlier, lasts eight days longer, and pollen production is up 21%; according to research published in the journal PNAS.

This concentration of pollen seems to trigger seasonal allergies in people who previously had no symptoms. Allergies have skyrocketed in recent years: In 2018, 7.7% of American adults had allergic rhinitis, but by 2021, that number had risen to around 25%.

The next few years are expected to be even warmer, with spring releasing more pollen into the air. The appearance of seasonal allergies depends to a large extent on two factors: genetic predisposition and the environment.. Some people are naturally predisposed to allergies, and climate change isn’t changing that, says Kathleen May, president of the American College of Allergy, Asthma, and Immunology. The environment, however, is changing. The correlation between temperature, carbon dioxide levels and pollen is very well documented. Scientists have known for decades that plants thrive in a warm greenhouse with high levels of carbon dioxide, with some species producing more pollen than other conditions.

An allergy occurs when a person’s immune system mistakenly treats a harmless agent as dangerous and begins to produce antibodies (IgE). When IgE detects a certain amount of allergen, it launches an attack on the “invader”, releasing chemicals that cause itching, sneezing, congestion. and other classic symptoms of an allergic reaction.

Some people are allergic without knowing it

Things are complicated by the fact that symptoms don’t manifest in everyone who develops antibodies every time they come into contact with a bit of pollen. With seasonal allergies, “it takes a certain amount of time or exposure” to trigger symptoms, May explains. In other words, some people who think they don’t have allergies actually do, they just haven’t been exposed to enough pollen to develop symptoms. The organism reacts when it “perceives that there is excessive amount,” says Méndez.

With pollen-filled air for long periods of time, climate change increases the chances of exceeding this threshold for the occurrence of an allergic reaction. “Some of the people who otherwise wouldn’t have symptoms will now start to develop symptoms,” May explains. And people who already have allergies are “definitely going to get worse.”

As the planet continues to warm, allergy sufferers will increase significantly, though exactly by how much is unclear. In Europe, forecast models indicate that the number of people allergic to the Ambrosia psilostachya plant will more than double, from 33 million to 77 million, by 2041 due to climate change.

We are not prepared for the effects of climate change on allergies. Over time, temperatures could become so high that pollen production lasts all year, as is already happening in the warmer parts of the US, notes William Andereg, a professor of biology at the University of Utah and lead author of a related study. The effects could be particularly severe in cities, where daytime temperatures can be up to seven degrees higher than in rural areas.

Seasonal allergies are linked to asthma, which can lead to hospitalization and make people more vulnerable to certain viruses, including the coronavirus. “There are also big societal impacts that we don’t think much about,” including reduced work productivity and poor student performance in school, Andereg noted. Obviously, the intensity of allergies is not among the most devastating effects of climate change, but pollen season is a reminder that even the smallest climate impacts are not necessarily simple.

Source: The Atlantic

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