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 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. Pollen season in general will start up to 40 days earlier in the spring and last up to 19 days longer than today under that scenario.
As atmospheric scientists, we study how the atmosphere and climate affect trees and plants. While most studies focus on pollen overall, we zoomed in on more than a dozen different types of grasses and trees and how their pollen will affect regions across the U.S. in different ways. For example, species like oak and cypress will give the Northeast the biggest increase, but allergens will be on the rise just about everywhere, with consequences for human health and the economy.
If your head is pounding at just the thought of it, we also have some good news, at least for knowing in advance when pollen waves are coming. We’re working on using the model from this study to develop more accurate local pollen forecasts.
Why Pollen Is Increasing
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 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. But temperature is only part of the equation. We found that the bigger driver of the future pollen increase will be rising carbon dioxide emissions.
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. We found that carbon dioxide levels may have a much larger impact on pollen increases than temperature in the future.