Climate change has made seasonal allergies increasingly common in the US and around the world.
Pollen levels are expected to increase 200% by the end of the century.
Allergy season is also getting longer each year, so more people are having symptoms.
More than 25 million Americans suffer itchy eyes, runny noses, and other allergy symptoms triggered by seasonal pollen, according to the Centers for Disease Control and Prevention.
That number has been on the rise in recent decades, driven by increasing pollen counts and longer warm seasons, Clifford Bassett, an allergy and infectious disease doctor, told Insider.
Bassett, an assistant professor of medicine at NYU Langone, said pollen counts have risen by approximately 20% in the past three decades, according to a study published in 2021. Allergy season has lengthened by as many as 20 days a year, meaning there is a larger window where people might experience symptoms.
People with asthma may also experience more severe symptoms as environmental irritants increase, and more of them will require medication to manage their health, Morgan McFall-Johnson previously reported for Insider.
Whether your allergy woes are mild or serious, it's worth noting that pollen counts are projected to increase 200% by the end of the century, according to a study published in Nature in March. The authors predicted that people with preexisting allergies or respiratory issues may find that their symptoms become more severe, and more people will develop seasonal allergies in the coming decades.
Plants are producing more pollen because of carbon emissions
Carbon dioxide is known as a "greenhouse gas." Not only do carbon emissions contribute to the warming of the planet, but they also have been linked to plant growth.
Plants use carbon dioxide to undergo photosynthesis and produce sugars that drive their growth. Between balmy temperatures and increased CO2 levels, plants have been churning out more pollen than they used to, according to a 2016 report published by Environmental Health Perspective.
The main source of carbon emissions — the extraction and burning of fossil fuels — also contributes to overall air pollution. Bassett told Insider that various pollutants can interact with airborne pollen, potentially worsening the severity of allergy symptoms.
During the COVID-19 pandemic, scientists in at least 31 countries have monitored how pollen might affect viral transmission. In a study published in March, they confirmed that high-pollen days correlated with subsequent spikes in COVID-19 infection rates.
Longer allergy seasons can have serious consequences for people at risk
Decades of global warming have allowed for an earlier start to allergy season, Bassett told Insider.
Normally, different types of trees produce pollen at different times of year. But a longer allergy season also means various species of plants are producing pollen around the same time, which could "multiply the misery" for people with allergies, according to the recent Nature study.
Higher temperatures also cause various plants to make more pollen, and a longer growing season means greater suffering for at risk groups with allergies.
Asthma, which can be triggered by pollen and pollutants, is more prevalent among racial minorities and families living below the poverty line. Discriminatory housing policies have historically relegated minorities to poorly-ventilated buildings in areas with high levels of pollution, increasing their risk of respiratory issues, especially during longer allergy seasons, according to Climate Central.
Read the original article on Insider