Hay Fever Misery Is Getting Worse: How Climate Change Is Extending Pollen Season and What You Can Do

Hay fever sufferers across the UK and Europe are experiencing longer and more intense pollen seasons due to climate change, with symptoms now lasting up to two weeks longer than in the 1990s, according to a major review by 65 scientists published in The Lancet Public Health.

The review, which analyzed pollen data from multiple European countries, found that rising global temperatures are causing plants to flower earlier and extend their pollination periods. For three common tree species—birch, alder and olive—the start of pollination has shifted one to two weeks earlier between 2015 and 2024 compared to the baseline period of 1991 to 2000.

Warmer temperatures not only lengthen the pollen season but also increase the intensity of pollen release, leading to more severe hay fever symptoms such as itchy eyes, sneezing and headaches. These changes are already contributing to rising rates of hay fever and reduced quality of life for sufferers, including increased absenteeism from work and school.

In the UK, recent warm and dry weather has created ideal conditions for birch tree pollen—a major hay fever trigger—to spread efficiently through the air. Experts describe these conditions as creating a “pollen bomb,” where high concentrations of pollen grains are released during peak early summer periods, worsening symptoms for millions.

Climate change is also linked to more extreme allergy events, such as thunderstorm asthma. During such storms, pollen grains are sucked into clouds, fragmented by moisture and lightning into smaller particles, and then released back to ground level in concentrated bursts that can trigger severe respiratory reactions in susceptible individuals.

While the prolongation of the pollen season is well-documented, researchers note that further study is needed to determine whether climate change is also increasing the total amount of pollen produced or making individual pollen grains more allergenic. Ongoing monitoring and public health guidance will be essential to help affected populations manage worsening symptoms.