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The Big Sneeze: Climate change will make pollen season more unpleasant


FILE – Floodwaters surround a bur oak tree southwest of Columbia, Mo., Wednesday, June 5, 2019. A study published Tuesday, March 15, 2022 in the journal Nature Communications details how warmer temperatures and the extra carbon dioxide in the air will make the pollen season even more troublesome than it is right now. (Kate Seaman/Missourian via AP, file)


Climate change has already lengthened allergy season and increased pollen counts, but you haven’t sneezed anything yet.

University of Michigan climatologists looked at 15 different plant pollens in the United States and used computer simulations to calculate how likely the allergy season will get worse by the year 2100. That’s enough for people with allergies have even more red eyes.

As the world heats up, allergy season will start weeks earlier and end days later – and it will be worse while it lasts, with pollen levels potentially tripling in some places, according to a new study published Tuesday in the journal Nature Communications.

Warmer weather allows plants to start flowering earlier and keeps them flowering later. Meanwhile, the extra carbon dioxide in the air from burning fuels such as coal, gasoline and natural gas helps plants produce more pollen, the study co-author said. , Allison Steiner, climatologist at the University of Michigan.

It is already happening. A study done a year ago by different researchers found that from 1990 to 2018, pollen has increased and allergy season is starting earlier, largely due to climate change.

Allergists say that pollen season in the United States used to start around St. Patrick’s Day and now often starts around Valentine’s Day.

The new study revealed that the allergy season would lengthen even further and the total amount of pollen would skyrocket. The duration and amount depends on the particular pollen, location and amount of greenhouse gas emissions released into the air.

With moderate reductions in greenhouse gas emissions from coal, oil and natural gas, the pollen season would start 20 days earlier by the end of the century. In the most extreme and increasingly unlikely warming scenario, the pollen season in much of America will start 40 days earlier than when it has typically started in recent decades.

Already about 30% of the world and 40% of American children suffer from pollen allergies, which hurt the economy through lost workdays and medical costs, said Yingxiao Zhang, a climate researcher at the University. of Michigan, lead author of the new study.

Allergies are particularly difficult for the 25 million Americans with asthma. That could make the problem worse for them, said Amir Sapkota, a professor of environmental health at the University of Maryland, who was not part of the research.

As allergy suffering increases in the United States, the Southeast will be hardest hit, Steiner said.

The start of the alder pollen season will shift more dramatically, a problem in the Pacific Northwest. Cypress pollen — which is particularly bad in Texas — will see one of the biggest increases.

Ragweed and grasses – common pollen allergies – will also have longer seasons and higher pollen counts in the future, Zhang said.

The University of Michigan team’s projected projections would represent about twice as many pollen problems as have occurred since 1990, said University of Utah biologist and climatologist Bill Anderegg.

“Overall, this is an incredibly important study,” said Anderegg, who was not involved in the new research. “This tells us that historical trends of longer and more severe pollen seasons are likely to continue, driven by climate change, and this will absolutely have significant health consequences of allergies and asthma among Americans.”


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Follow Seth Borenstein on Twitter at @borenbears.


The Associated Press Health and Science Department is supported by the Howard Hughes Medical Institute Department of Science Education. The AP is solely responsible for all content.