The climate crisis is multiplying the miseries faced by people with allergies, with new research finding that the pollen season in North America is now, on average, 20 days longer than it was three decades ago.
Rising global temperatures are helping to prolong the time period, usually in the spring, when pollen is released by plants, trees and grasses, according to the study, published in Proceedings of the National Academy of Sciences.
In an analysis of 60 pollen collection stations in the United States and Canada, the pollen season is now 20 days longer on average than in 1990. The season is also becoming more intense, with significantly greater amounts of pollen being detected .
This increase is strongly associated with global warming, with researchers using climate modeling to show that climate change is responsible for at least half of the additional days of pollen activity. There is also evidence that the increasing concentration of carbon dioxide in the atmosphere may be helping to drive the increase.
“We are getting warmer winters, warmer springs and earlier springs and this is causing a lot of that,” said William Anderegg, co-author of the study and a scientist at the University of Utah, who was personally interested in the topic because of his own fever. seasonal hay. “This is a very clear example that climate change is already here, in essence it is here with every breath we breathe. The health impacts are with us and can get worse. “
Small grains of pollen, expelled to propagate plants, can trigger seasonal allergies in some people, causing sneezing, itchy eyes and a runny nose. The pollen season can also worsen other conditions, such as asthma, and these diseases have been linked to poor school performance and indirect economic impacts.
Anderegg said the pollen season is likely to be increasing in other parts of the world as well, although some regions are limited by the availability of water. “We don’t really know how far it will go from here, we don’t have a lot of pollen monitoring compared to other types of air pollution,” he said, adding that a public health response could include warnings on high pollen days and air filters. for buildings.
The study is the first to be able to attribute the pollen’s growing season to climate change, according to Kristie Ebi, an epidemiologist at the University of Washington who was not involved in the research. “As the climate continues to change, without additional adaptation to prepare and manage the impacts … the number of asthma and allergy cases due to aeroallergens is expected to increase,” she said.
Aaron Bernstein, an academic at Harvard School of Public Health and a doctor at Boston Children’s Hospital, said he is seeing more and more children suffering from allergies and asthma.
“The future is now,” he said. “We are seeing health damage from climate change more clearly each year. The worsening of the allergy season is one of the many reasons for important climate action now, not only to prevent immense damage, but to promote a healthier and more just life, and sustainable world. “