Allergy Season Getting Longer


Allison L. Steiner, a professor of atmospheric science at the University of Michigan, and Yingxiao Zhang, a doctoral student, write on The Conversation magazine that pollen season is getting longer and more intense because of climate change.

Our latest study finds that the U.S. will face up to a 200 percent increase in total pollen this century if the world continues producing carbon-dioxide emissions from vehicles, power plants, and other sources at a high rate. Under that scenario, the spring pollen season will generally start up to 40 days earlier and last up to 19 days longer than it does today.

The higher temperature will extend the growing season, giving plants more time to emit pollen and reproduce. Carbon dioxide, meanwhile, fuels photosynthesis, so plants may grow larger and produce more pollen.

– Yingxiao Zhang and Allison L. Steiner on The Conversation

The authors explain that to understand allergy, we should understand how pollen are produced in the first place.

Pollen—the dustlike grains produced by grasses and plants—contains the male genetic material for a plant’s reproduction.

How much pollen is produced depends on how the plant grows. Rising global temperatures will boost plant growth in many areas, and that, in turn, will affect pollen production (longer season). But temperature is only part of the equation. We found that the bigger driver of the pollen increase will be rising carbon-dioxide emissions.

The duo warn “Increased pollen levels will have a much broader impact than a few sniffles and headaches. Seasonal allergies affect about 30 percent of the U.S. population, and they have economic impacts, including health-care costs and missed working days. In the coming years, those impacts will only intensify.”

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