Earth day: you're not imagining it - your allergies are getting worse!

Dr Yvonne Boose of BreezoMeter explains why climate change is bad for our health and our allergies

This Earth Day, we wanted to give proper attention to a very important issue impacting our wonderful planet - climate change. There’s many things that climate change affects in our everyday life, but did you know it also has a direct impact on our seasonal allergies? To understand the relationship between climate change and pollen production in more detail, we spoke to BreezoMeter’s environmental expert, Dr Yvonne Boose.

The science behind pollen allergy

Many of us associate seasonal allergies with the blooming of beautiful flowers at springtime each year. However, allergic pollen is actually created by a wide range of plant species - many of which don’t even flower. These plants are grouped according to three main categories: Grass, Weed & Trees. It’s important to realize that not all plants within these categories produce allergic pollen, and that different allergy sufferers will probably be sensitive to different types of pollen.

Pollination is essentially nature’s way of ensuring plant offspring for the next generation: The pollen grains contain the DNA required to produce a new plant.

The impact of a changing climate on pollen production

Our changing climate affects pollen levels and our seasonal allergies in a number of ways: The level of pollen in the air, the timing of allergy seasons, and how we experience seasonal allergy-linked symptoms. 

Carbon dioxide (CO2) is both a greenhouse gas & “plant food”

CO2 is very important for understanding the connection between pollen production and climate change: It operates both as the main greenhouse gas in Earth’s atmosphere, contributing to rising temperatures of the planet and is an essential ingredient for plant growth. Essentially, CO2 provides the source of carbon plants need to make sugars during photosynthesis. 

When plants are exposed to both warmer temperatures and higher levels of CO2, they grow more rapidly and produce more pollen than they might otherwise have done.

A new study conducted by the Proceedings of National Academy of Sciences (PNAS) examined pollen concentrations over the last three decades in North America, and discovered that pollen concentrations in North America have increased by 21% during this time. The largest increases were seen in Texas and the MidWest. According to this study, these pollen increases have been driven by rising temperatures and increased CO2 concentrations.

Rising temperatures mean longer allergy seasons

By way of impacting growing seasons, researchers also believe that warmer temperatures and higher atmospheric carbon dioxide levels function to alter the timing of flowering seasons and when pollen gets produced. 

For example, it’s been observed that pollen seasons are now starting earlier and ending longer in the Northern hemisphere. One study found that between 1995-2011, warmer temperatures in the US caused the pollen season to be 11 to 27 days longer on average. 

The impact of climate change on season start and end times has the knock-on effect of making pollen seasons more difficult to predict using traditional observational and time-based methods, which is why attention is now turning to methods that are driven more by big data and complex algorithmic modeling.

Same plants, different places: ragweed invades Europe

As climate change impacts our ecosystem more broadly, plants can begin to grow in new habitats that they might not traditionally have been found in. The correct term for this phenomena is “dispersal”. Relocation to a new site is considered an adaptive function to ensure plant survival, but climate change is also driving plant migration here.

Ragweed - which is a common pollen allergen - is a perfect example of this “dispersal” in action; although this plant was native to North America, it has already spread across much of Europe. It is predicted that ragweed pollen concentrations in Europe will be 4 times higher than they are now by 2050 - partly due to climate change.

“Thunderstorm Asthma” and the impact of extreme weather 

Record-breaking heat waves, sudden freezes, shock flooding & larger wildfires - we’re all becoming familiar with these kinds of headlines as climate change contributes to the likelihood of extreme weather events.

For seasonal allergy, extreme weather events make previously rare phenomena like ‘thunderstorm asthma’ more likely. Thunderstorm asthma occurs when there is a lot of pollen in the air, and certain weather conditions happen at once - hot, dry, windy & stormy.

When this mix of conditions occurs, pollen grains can burst into smaller pieces, making it easier for particles to be blown around and inhaled - risking severe respiratory symptoms. In November 2016, Melbourne experienced a record-breaking thunderstorm asthma event - resulting in a surge of hospital admissions. Researchers concluded that increased levels of pollen in the air were climate-change linked, highlighting the reality that reliable pollen monitoring was fast-becoming an urgent public health issue for Australians.

The bottom line: climate change increases our risk of seasonal allergy symptoms 

The World Allergy Organization states that as many as 10-30% of adults and 40% of children around the globe already suffer from seasonal allergy, and research points to an increased risk of allergic reaction over the last few decades. Ultimately, longer pollen seasons and higher concentrations of pollen in the air risks higher levels of exposure to pollen which can trigger allergy symptoms among sufferers.

It’s more important than ever to be aware of the air we breathe and to understand the impact of a changing climate on our health. 

About Dr. Yvonne Boose - I am a full-time atmospheric scientist at BreezoMeter, and feel privileged to share my knowledge about air quality with a wider audience on a regular basis. I strongly believe that science is for the many, not the few. The more we all understand the impact of the environment on our health, the more we can take action to manage harmful exposure and make healthier decisions. I’d like to thank Fluo Labs for allowing me to contribute this piece! Read more of my content here.