Guest essay by Eric Worrall
The University of Michigan models suggest that increased plant growth due to warmer temperatures will increase pollen allergies.
Pollen season is getting longer and more intense with climate change – here’s what allergy sufferers can expect in the future
Published: March 16, 2022 3.08 a.m. AEDT
Yingxiao Zhang
Ph.D. Atmospheric Science Student, University of MichiganAllison L. Steiner
Professor of Atmospheric Science, University of MichiganBelieve in yourself, allergy sufferers – new research suggests pollen seasons will be longer and more intense with climate change.
Our latest research shows that the US will face up to 200% total pollen counts for this century if the world continues to produce carbon dioxide emissions from vehicles, power plants and other sources at high rates. Pollen season would generally start up to 40 days earlier in spring and last up to 19 days longer than now under that scenario.
Equal ozone scientists, we study how air and climate affect trees and plants. While most studies focus on overall pollen, we zoomed in more than a dozens of different types of grass and trees and how their pollen will affect regions across the United States in different ways. For example, species like oak and cypress will bring the biggest gains to the Northeast, but allergens will increase everywhere, with consequences for human health and the economy.
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How much pollen is produced depends on how the plant grows. Rising global temperatures will spur plant growth in many areas, and that will affect pollen production. But temperature is only one part of the equation. We see that greater impetus for future pollen increases will increase carbon dioxide emissions.
Higher temperatures lengthen the growing season, giving plants more time to pollinate and reproduce. Meanwhile, carbon dioxide provides fuel for photosynthesis, so plants can grow larger and produce more pollen. We found that carbon dioxide levels can have a much larger impact on pollen increases than future temperatures.
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Summary of the study;
Projected climate changes in pollen season length and intensity over the continental United States
Yingxiao Zhang & Allison L. Steiner
Nature Communications episode 13Number of articles: 1234 (2022) Quote this article
abstract
Atmospheric conditions affect anemones pollen dispersal, the timing and magnitude of which will be altered by climate change. As simulated with pollen emission models and future climate data, warmer end-of-century temperatures (4–6 K) shift the onset of spring emissions 10–40 years earlier day and summer/fall grass and grass 5–15 days later and lengthen section length. Phenomenological variation depends on the temperature response of individual taxa, with convergence in some regions and divergence in others. Temperature and precipitation change daily pollen emission maximums from −35 to 40% and increase total annual pollen emissions by 16–40% due to environmental changes and pollen production controlled by temperature. Increase CO in the atmosphere2 could increase pollen production, and doubling production with climate increases end-of-century emissions by as much as 200%. Land cover change alters the distribution of pollen emitters, however the effects are relatively small (<10%) compared to climate or CO2. These simulations indicate that increased pollen intake and longer seasons increase the likelihood of seasonal allergies.
Read more: https://www.nature.com/articles/s41467-022-28764-0
For starters, I’m pretty sure allergies won’t be an issue in the future. Today’s medicine is much better than what was available when I first had my symptoms. I would be surprised if allergies remained an important issue in the next few decades, let alone the end of this century.
But there is an immediate rebuttal to this claim. As an asthmatic who also has a pollen allergy, I personally find the issue to be more complicated than the scientists are suggesting.
There’s a reason older people move to warmer places like Florida or Queensland, even if they have asthma or allergies.
When I moved from cold England to subtropical Australia, my allergies became more manageable.
Why? Although my new home pollen season is longer, it seems to be more widespread.
Pollen booms in cold places like the UK tend to be short-lived but extremely intense. It must be intense, because the growing season is short. Pollination for many plants must take place at the very beginning of the growing season, or else the fruit and seeds may not mature quickly enough to be ready before frost.
In warmer climes, plants will be under less pressure to fight for every precious day of the growing season. The tree flowers most of the year, and fruits such as citrus can continue to grow throughout the winter, usually ripening the following spring.
Overall, my experience has been that moving to a warmer climate has helped control my asthma and hay fever. I encounter my other major trigger, cold air, less often in Australia than in the UK. The reduction in exposure to cold air and the absence of drastic changes in pollen exposure, made it much easier for me to control my asthma and hay fever with medication.
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