Every spring many allergy they appear in the same sequence, but the symptoms seem to worsen for many, and climate change is likely to blame.

“Allergy seasons are getting longer and more intense,” says Kenneth Mendes, CEO of the US Asthma and Allergy Foundation. Plants produce more pollen over a longer period of time, and it’s not just that warmer temperatures lengthen the growing season for plants. Carbon dioxide itself contributes to the production of pollen.

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

This concentration of pollen appears to cause seasonal allergies in people who have not previously had symptoms. Allergies have skyrocketed in recent years, with 7.7% of American adults suffering from allergic rhinitis in 2018, but by 2021, that number has risen to about 25%.

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

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

Some people suffer from allergies without even knowing it.

To complicate matters, not all of those who develop antibodies each time they come into contact with a small amount of pollen show symptoms. May explains that with seasonal allergies, “it takes a certain amount of time or exposure” to cause symptoms. 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 body reacts when it “perceives that there is surplus quantity,” Mendes notes.

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

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

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

Seasonal allergies are associated with asthma, which can lead to hospitalization and make people more vulnerable to certain viruses, including the coronavirus. “There are also serious social consequences that we don’t think much about,” including lower productivity and poor student performance in school, Andereg said. Allergy intensity is obviously not among the most devastating impacts of climate change, but pollen season is a reminder that even the smallest climate impacts are not necessarily simple.

Source: Atlantic.