Climate change blamed for pollen proliferation

Climate change has already made allergy season longer and pollen counts higher, and what’s coming is even more to sneeze at.

Climate scientists at the University of Michigan looked at 15 different plant pollens in the United States and used computer simulations to calculate how much worse allergy season will likely get by the year 2100. It is enough to make allergy sufferers even more red-eyed.

As the world warms, allergy season will start weeks earlier and end many days later, and it will be worse while it lasts, with pollen levels that could as much as triple in some places, according to a new study Tuesday in the journal Nature Communications.

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

It is already happening. A study a year ago from different researchers found that from 1990 to 2018, pollen has increased and allergy season is starting earlier, with much of it because of climate change.

Allergists say that pollen season in the U.S. used to start around St. Patrick’s Day, but now often starts around Valentine’s Day.

The new study found that allergy season would stretch even longer and the total amount of pollen would skyrocket. How long and how much depends on the particular pollen, the location and how much greenhouse gas emissions are put in the air.

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

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

Allergies are especially difficult for the 25 million Americans with asthma. This could make the problem much worse for them, said Amir Sapkota, a University of Maryland environmental health professor, who wasn’t part of the research.