Climate Change Is Making Allergy Season Worse

New research finds climate change is making allergy season arrive earlier and bring higher pollen loads in North America

A bee (right) collects pollen from the inside of a sunflower (left)
The phenomenon of increasing yearly pollen loads is accelerating. PATRICK PLEUL/DPA/AFP via Getty Images

Human-caused climate change is making allergy season longer and more severe, reports Seth Borenstein for the Associated Press.

In North America, there is now 21 percent more pollen in the air in that begins wafting an average of 20 days earlier each year compared to 1990, according to a new study, published this month in the journal the Proceedings of the National Academy of Sciences.

Per the AP, past studies have arrived at similar conclusions, but the new research is more comprehensive and does the work of tying the phenomenon to climate change.

"A number of smaller-scale studies—usually in greenhouse settings on small plants—had indicated strong links between temperature and pollen," says Bill Anderegg, a biologist and climate scientist at the University of Utah who is the study’s lead author, in a statement. "This study reveals that connection at continental scales and explicitly links pollen trends to human-caused climate change."

The study finds climate change was responsible for roughly half of the observed trend of earlier pollen season start dates and eight percent of the added pollen in the air, John Schwartz of the New York Times reports. Additionally, per the Times, the phenomenon of increasing yearly pollen loads is accelerating.

“This is a crystal-clear example that climate change is here and it’s in every breath we take,” Bill Anderegg, a biologist and climate scientist at the University of Utah who is the study’s lead author, tells the AP.

Anderegg tells the Times that the longer, harsher pollen seasons were most intensely felt in Texas, the Midwest and the Southeast. Pollen seasons were mildest in New England and in states around the Great Lakes. The plants responsible for all the extra pollen were mainly trees, rather than grasses and weeds, Anderegg tells the Times.

For the study, Anderegg and his co-authors used data from 60 pollen monitoring stations between 1990 and 2018. Researchers then compared that data with nearly two dozen climate models to see if there were correlations between intense climate change and the pollen monitoring stations’ measurements.

“Our results indicate that human-caused climate change has already worsened North American pollen seasons,” the authors write.

According to the AP, the study lays the situation out like this: As humans flood Earth’s atmosphere with greenhouse gases, the planet warms and that makes spring start earlier for plants that release pollen. Moreover, the extra carbon dioxide in the atmosphere also stimulates plants to produce and release more pollen.

Speaking with the Times, Anderegg says he and his co-authors “expect this to get worse in the next couple of decades.”

Making allergy season worse might just sound like a boon for tissue companies and antihistamine manufacturers, but allergies have serious public health impacts. According to the Times, for people suffering from asthma, an earlier pollen season may increase their risk of hospitalization. Other studies have shown that when pollen loads are peaking students do less well in school and people may be more likely to catch respiratory viruses.

"Climate change isn't something far away and in the future. It's already here in every spring breath we take and increasing human misery," Anderegg says in the statement. "The biggest question is—are we up to the challenge of tackling it?"