Why Climate Change Is Making Hay Fever Worse and Lasting Longer: Causes, Impacts, and How to Cope

Climate change is extending pollen seasons and worsening hay fever symptoms for millions of people, according to a major review of scientific evidence published in recent years.

A new report by 65 scientists from around the world, published in the journal Lancet Public Health, found that climate change has “prolonged the pollen season” across Europe and other regions. The study examined three common trees—birch, alder, and olive—and determined that pollination now begins one to two weeks earlier than it did between 1991 and 2000.

Professor Joacim Rocklov of the University of Heidelberg, one of the study’s authors, explained that the changes are visible in both northern and southern Europe, with flowering seasons starting earlier and lasting longer due to rising temperatures.

Warmer, dry conditions are also creating ideal environments for pollen to spread through the air, leading to what some experts have described as “pollen bombs”—periods when pollen concentrations spike dramatically, intensifying symptoms for allergy sufferers.