Why allergy season will last even longer this year

Allergy season has made its unwelcome entrance earlier than usual this year.

Now, experts warn this trend may be the new normal as pollen activity has ramped up in recent years — thanks to climate change.

A study published in Nature Communications found that pollen allergy season could start up to 40 days earlier and last 19 days longer by the year 2100, with the annual pollen count jumping anywhere from 40% to 200% above baseline.

Researchers at the University of Michigan developed a predictive model to analyze the impact climate change would have on 15 of the most common pollen types.

They explained that rising global temperatures are to blame for the expected increased intensity of seasonal allergies as trees, weeds and grasses awaken to spring earlier and more intensely.

Annual pollen emissions are forecasted to increase by 40% with temperature and weather changes alone, but could jump to up to 250% if carbon dioxide and other emissions produced by the combustion of coal, gasoline and natural gas are allowed to increase at their current rates.

“Pollen-induced respiratory allergies are getting worse with climate change,” said the study’s first author, Yingxiao Zhang, a University of Michigan graduate student and research assistant who studies climate and space sciences in the College of Engineering.

In a statement for the school’s website, Zhang added, “Our findings can be a starting point for further investigations into the consequence of climate change on pollen and corresponding health effects.”

Previous research has also shown that pollen seasons have grown longer and more potent in recent years and are expected to continue on that path.

Historically, pollen season in the US would kick off around St. Patrick’s Day in mid-March. Allergists now estimate that the date has since moved up to Valentine’s Day, around the second week of February.

A recent report from the National Oceanic and Atmospheric Administration noted that much of the country experienced record or near-record warm temperatures last month as the average rose 2.7 degrees above the 20th-century standard.

Take New York City, which experienced a noticeably mild winter this year. The Big Apple didn’t experience its first snow of the season until February when just under a half-inch of snow coated Central Park. The flurries marked the latest “measurable” snowfall NYC has experienced since 1869, when the city first began keeping weather records, Fox Weather meteorologist Mathieu Blue previously told The Post.

Warmer winters and earlier springs will be difficult for the 30% of adults and 40% of children who suffer from allergies in the US, and especially difficult for the 25 million Americans with asthma, according to the Allergy and Asthma Foundation of America.

Environmental allergy symptoms vary ranging from watery eyes and sneezing to difficulty breathing and, in extreme cases, full-blown anaphylaxis.