Is your hay fever getting worse? It could be climate change

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Did your hay fever start earlier this spring? The coughing, the sneezing, those terrible itching eyes? You are not alone, and it might get worse in coming years as climate change extends the season, experts say.

About 15 per cent of Australians have hay fever, with those between 25 and 44 years old most likely to suffer during spring. Hay fever is an allergic response when substances including pollen from grasses and trees, dust mites or mould come into contact with the nose and eyes.

University of Macquarie professor Paul Breggs says climate change could impact pollen patterns.Credit: Steven Siewert

Plants are producing their pollen earlier and in higher amounts. This is because of several factors, including their locations, the species and increases in temperature and carbon dioxide emissions, research from the University of Michigan shows.

Plants rely on carbon dioxide to fuel photosynthesis, so they may grow larger and produce more pollen with increased gases in the atmosphere.

Macquarie University’s Professor Paul Beggs said plants and animals had developed unique relationships over many years, but changes in pollen patterns were occurring very rapidly and could impact that delicate dance. Meanwhile, plants that relied on wind to spread their seeds were likely to be affected by the weather patterns.

“[Increased emissions] will have an impact on all types of plants and a whole range of animals as well,” Beggs said.

The University of Michigan research shows that parts of the United States could have a 200 per cent increase in pollen this century, with the season starting up to 40 days earlier in the spring and lasting up to 19 days longer if current global warming trends continue.

Australia’s experience could be somewhat similar, although longitudinal data was lacking, Beggs added.

Data from the Australian Institute published in 2020 found that summer was, on average, one month longer than it was 100 years ago, while winter was more than three weeks shorter. For example, in Port Macquarie in New South Wales, summers have increased by 48 days.

Dr Brett Summerall, the chief botanist with Sydney’s Botanic Gardens and Centennial Parklands, said regions with colder winters and a sudden swing to spring might have flowers blooming faster over the coming years, and this could lead to earlier hay fever symptoms.

Summerall pointed to the mild winter Australia had experienced and said this could be behind several plants flowering early. Among the early bloomers are Sydney’s purple jacaranda trees.

Changes in temperatures are also causing plants and animals to spread to new areas, with those favouring tropical climates now found further south.

While Victoria has better monitoring of potential thunderstorm asthma events, thought to be triggered by a mix of high levels of grass pollen and a certain type of thunderstorm, the rest of the country lags.

Beggs said Australia poorly measured pollen in that it relied on someone manually collecting and analysing samples – a method that was developed in the 1950s.

A new trial was hoping to change that, he said.

Other countries collect pollen data automatically, drawing on newer technology, which then feeds the pollen count and future predictions into daily forecasting.

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