This year's Earth Day was all about 'restoring our earth' by raising awareness of climate change and the impact it has on our ecosystems, societies and daily lives, so I was delighted to work on this earth day-dedicated piece with the seasonal allergy specialists, Fluolabs!
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 realise 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, but also as 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 modelling.
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’ & 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 together, 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.