The climate crisis is extending the misery for hay fever sufferers, with new research showing the pollen season in North America is now 20 days longer on average than in 1990. The study, published in the Proceedings of the National Academy of Sciences, also found that pollen levels have become more intense over the same period.
Researchers analysed data from 60 pollen-collecting stations across the United States and Canada. They found that the season has lengthened significantly, with rising global temperatures playing a key role. Climate modelling suggests that at least half of the extra days of pollen activity can be attributed to climate change.
'We are getting warmer winters, warmer springs and earlier springs and that is driving a lot of this,' said William Anderegg, co-author of the study and a scientist at the University of Utah. 'This is a really clear example that climate change is already here, in essence it's here in every breath we take. The health impacts are with us and likely to get worse.'
The pollen grains, which trigger seasonal allergies in many people, cause symptoms such as sneezing, itchy eyes and runny noses, and can worsen conditions like asthma. The authors note that pollen seasons are probably lengthening elsewhere, though monitoring is limited. They call for public health measures such as warnings on high-pollen days and improved air filtration in buildings.
Kristie Ebi, an epidemiologist at the University of Washington not involved in the research, said the study was the first to attribute the growing pollen season to climate change. 'As the climate continues to change, without additional adaptation … the numbers of cases of asthma and allergies due to aeroallergens would be expected to increase,' she said. Aaron Bernstein of Harvard School of Public Health added: 'The future is now. We are seeing the health harms of climate change more clearly each year.'
