Opinion: How to mitigate climate change’s impact on allergies

July 26, 2023—Heat stroke and heat exhaustion aren’t the only heat-related illnesses on the rise amid extreme heat caused by climate change. Seasonal allergies and asthma are also getting worse as temperatures climb, according to several experts from Harvard T.H. Chan School of Public Health’s Department of Environmental Health.

Kari Nadeau, department chair and John Rock Professor of Climate and Population Studies; incoming doctoral student Leah Martin; and Jinia Sarkar, SM ’24, wrote in a July 23 opinion article in The Messenger that the excess of carbon dioxide in the Earth’s atmosphere—a result of burning fossil fuels, and a driver of extreme heat—leads allergenic plants to produce more pollen for longer. From 1990 to 2018, pollen season lengthened by 20 days, and pollen concentrations increased by 21%. More pollen can exacerbate allergies among the roughly quarter of American adults who suffer from them, as well as trigger more asthma attacks, the co-authors noted. Black Americans and other racial minorities face even steeper risks, driven by historical racial segregation and bias that makes them more likely to be hospitalized or die from asthma and to live in communities with greater air pollution.

While there are measures individuals can take to manage their symptoms during longer allergy seasons, system-level solutions to climate change and its health impacts are what’s truly needed, according to the co-authors. These solutions include transitioning to clean energy; ensuring that health care is accessible for all, particularly for populations disproportionately impacted by climate change; and improving air quality and addressing other factors that exacerbate allergies and asthma, such as traffic emissions.

Read the opinion piece in The Messenger: Sneezing, Coughing, Runny Nose: Unexpected Symptoms of Extreme Heat