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Pollen season is getting longer and more intense with climate change – here’s what allergy sufferers can expect in the future

Pollen season is getting longer and more intense with climate change – here’s what allergy sufferers can expect in the future

6 maps showing differences in how types of plant pollen seasons will change. Ambrosia, better known as ragweed, has the greatest increase.

Brace yourselves, allergy suffers – new research shows pollen season is going to get a lot longer and more intense with climate change.

Our latest study reveals that the U.S. will face significant challenges. You can get as high as 200% in your profitsIf the world continues to produce high levels of carbon dioxide from power plants, vehicles, and other sources, there will be a significant increase in total pollen by the end of this century. The pollen season will begin 40 days earlier in spring and last as long as 19 days longer under this scenario.

As Atmospheric ScientistsWe study the effects of climate and atmosphere on trees and plants. Although most studies are focused on pollen, we zoomed in to more than just the pollen. Dutzend different kinds of grasses, treesHow their pollen will impact different regions in the U.S. The Northeast will see the greatest increase in species like oak and Cypress, but allergens everywhere will be increasing, with negative consequences for human health as well as the economy.

6 maps showing differences in how types of plant pollen seasons will change. Ambrosia, better known as ragweed, has the greatest increase.
The maps to left show the average length of the pollen season in days for three types: platanus (or plane trees), such as sycamores and betula (or birch); and ambrosia (or ragweed). The right maps show the expected changes in total days at the end of this century if carbon dioxide emissions keep rising at a high pace.
Zhang and Steiner 2022

We have good news for you, at least to know when the next pollen wave is coming. We’re working on using the model from this study to develop more accurate local pollen forecasts.

Why pollen is on the rise

Let’s start with the basics. Pollen – the dust-like grains produced by grasses and plants – contains the male genetic material for a plant’s reproduction.

How the plant grows will affect how much pollen is produced. Rising temperatures will cause a rise in plant growth in many parts of the world, which in turn will impact pollen production. Temperature is only part. We found that The largest driver of the future increase in pollen isThere will be an increase of carbon dioxide emissions.

Higher temperatures will prolong the growing season and give plants more time for pollen production and reproduction. Carbon dioxide, in turn, fuels photosynthesis so plants can grow larger and produce greater amounts of pollen. We found that carbon dioxide levels could have a greater impact on pollen production than temperature.

Dust-like pollen falls from pine cones

A Norway Spruce cone in Virginia releases pollen.
Famartin/Wikimedia, CC BY ND

Regions will have different pollen changes

We looked at 15 different types of pollen and did not treat all pollen the exact same way as previous studies.

Typically, pollination begins with leafy deciduous tree in spring and late winter. Alder, birch, and oak are the most common deciduous trees that can cause allergies. However, there are other options, such as mulberry. The summer brings out grasses, then ragweed in the late summer. Evergreen trees in the Southeast like mountain cedar or juniper (all part of the cypress family), start in January. In Texas, “cedar fever” is the equivalent of hay fever.

We found that the Northeast has pollen seasons for many allergenic trees. There is more overlapAs temperatures and carbon dioxide emitteds rise, so does the cost of living. It used to be that oak trees would first release pollen, then birch would then pollinate. We see more overlap in their pollen seasons.

How pollen season spreads over the U.S. in one year. Yingxiao Zhang, and Allison Steiner.

Due to higher temperatures in the northern regions, pollen seasons will generally change more in the north than the south.

The future is bright for the Southeast, which includes Florida, Georgia, and South Carolina. Because of the early alder pollen season, peak pollen season in the Pacific Northwest will likely occur a month earlier than usual.

There is a silver lining: We can improve pollen forecasting

Most pollen forecasts provide a broad estimate right now. Part of the problem is that there aren’t many Stations for observationFor pollen counts. Many are managed by allergy clinics and there are less that 100 stations across the country. Michigan, where we live, doesn’t have any.

It’s a very labor-intensive process to actually measure different types of pollen. Current forecasts are therefore subject to uncertainty. These forecasts are likely to be based in part in what a station has observed in past years and the weather forecast.

A person's hands jostle a pine branch to collect pollen
The labor-intensive process of sampling pollen for regional forecasts is possible.
HelenaAnna/Wikimedia, CC BY ND

If our model is integrated into a forecasting framework it could provide more targeted forecasts for pollen across the country.

Satellite data and ground surveys can help us estimate the location of trees. We also know how temperature influences when pollen comes out – what we call the phenology of the pollen. We can use meteorological factors such as wind, relative humidity, precipitation, to determine how much pollen is in the air. Atmospheric models can show how pollen moves around and how it blows around to create a real time forecast.

All of that information allows us to look at where pollen might be in space and time, so people dealing with allergies will know what’s coming in their area.

We’re currently talking with a National Oceanic and Atmospheric AdministrationLab about how to incorporate that information into an air quality forecasting tool.

Dozens of round, spiky pollen grains attached to a plant
Colorized and magnified ragweed pollen grains
Bob Sacha/Corbis Documentary via Getty Images

Long-term projections of pollen are still in flux. For example, scientists don’t fully understand why plants produce more pollen in some years than others. There’s not a good way to include that in models. It’s also not fully clear how plants will respond if carbon dioxide levels go through the roof. It’s also difficult to capture residential trees and ragweed. Although there are not many ragweed surveys in the United States that show where these plants are found, this can be improved.

Already, pollen levels are on the rise

A study from 2021 showed that the Overall pollen seasonWas already about North America: 20 days longerPollen concentrations were about 21% higher in 1990 than they were in 1990.

Future increases in pollen levels will have a far greater impact than just a few sniffles or headaches. Seasonal allergies can affect About 30% of the population is affluent.They have economic impact on the economy. Health costsTo Days off.

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