Reports suggest that climate change and warming temperatures have made seasonal allergies worse over the past several decades. Since an estimated 81 million people in the United States (US) suffer from spring allergies, from pollen on trees to weeds and grasses, this changing environment effect raises significant health concerns, according to The New York Times.
Due to climate change, temperatures are rising, affecting plant growth and extending the spring allergy season by 20 days. Climate experts predict that pollen levels will be higher this year than the historical average across 39 states, according to bbc.com. The Asthma and Allergy Foundation of America (AAFA) released its 2025 report regarding the places most affected by pollen in the US. The report highlights that climate change is the driving factor of worsening allergy seasons, particularly in the southern and eastern areas where allergy seasons can last all year. For example, November was the warmest month on record in Louisiana. Since warmer weather signals plants to bloom, pollen seasons are starting earlier and lasting longer, according to aafa.org. Ultimately, as the planet continues to warm, plants across North America will produce more pollen in higher concentrations, according to The New York Times.
In addition to rising temperatures, carbon dioxide (CO2) levels are increasing in the atmosphere due to various human activities and other factors. Many plants associated with spring allergies thrive on CO2, reflecting worsening allergy trends. To test this theory, researchers conducted an experiment where they grew plants under elevated CO2 levels to stimulate potential effects of the rising CO2 levels on plants. They found elevated CO2 levels increased the amount of grass pollen in plants by 50 percent. Future projections show airborne grass pollen could increase as much as 200 percent. These findings suggest that climate change will have a significant impact on human health if greenhouse gas emissions continue to rise, according to journals.plos.org.
Mr. Lewis Ziska, a professor of environmental health sciences at Columbia University’s Mailman School of Public Health, wrote Greenhouse Planet, where he outlined how increased CO2 levels affect plants and everyone who relies on them. Mr. Ziska also ran an experiment where he grew plants at increased CO2 levels, according to cup.columbia.edu. Mr. Ziska spoke about what occurred during his experiment, according to bbc.com.
“Every time we cranked up the carbon dioxide, the ragweed plants responded,” Mr. Ziska said, according to bbc.com. “They grew more. They produced more pollen. And there was some evidence that they were producing a more allergenic form of the pollen, one that could induce your immune system to respond even to a greater extent than had been in the past.”
Those who live in the New York City (NYC) area experience a longer spring allergy season than usual, and the peak pollination period arrives sooner. For a majority of the Tri-State area, peak pollination occurs from early to the middle of May. This period can vary depending on how early temperatures warm. Because of the climbing temperatures, this year, climate experts anticipate a 180 day allergy season in the Northeast, extending 20 days longer than is usual for this area, according to cbsnews.com.
Climate experts note how seasonal allergies are technically due to an overactive immune system, when the immune system detects and reacts against foreign substances in the body, like pollen or ragweed, according to health.harvard.edu. The body then attacks itself as if they were a dangerous threat. There are a variety of possible symptoms for seasonal allergies such as nasal congestion, eye allergies known as seasonal allergic conjunctivitis (SAC), and skin irritation. Experts also identify these symptoms as hay fever, , according to lung.org.
Overall, allergies can have serious impact on one’s quality of life, especially for those who suffer from a chronic lung disease like asthma or Chronic Obstructive Pulmonary Disease (COPD). For these individuals, a mild case of hay fever can put them at risk for severe health issues. Additionally, extreme temperatures can increase the risk of heart disease and respiratory health complications. It can also impact mental health, including anxiety, depression and agitation, according to lung.org. Ms. Melanie Carver, Chief Mission Officer for AAFA, commented on the effects climate change has on human health.
“Increased pollen exposure can make it difficult to manage and control allergies and asthma, causing more missed work and school days, emergency room visits, and hospital stays,” Ms. Carver said, according to aafa.org. “In the short-term, adopting allergy management strategies can reduce the negative impacts of pollen allergies. Long-term, we should be looking at policy change to reduce the impact of climate change.”
Featured Image by Lilia Newman ’27
