"Thunderstorm asthma": Seasonal allergies get aggravated by climate change

Climate change is intensifying seasonal allergies and contributing to rare but dangerous “extreme allergy events,” according to experts. One of the most striking examples is “thunderstorm asthma,” a phenomenon where weather systems break apart pollen particles and spread them in highly concentrated forms, triggering severe asthma attacks. This was tragically illustrated in Australia, when a thunderstorm led to a massive public health crisis back in 2016.

As the storm developed, it sucked vast amounts of pollen into the atmosphere. Once inside the clouds, lightning, rain, and humidity shattered the pollen into microscopic fragments, which were then dispersed back to the ground. According to an article by the BBC these tiny particles were easily inhaled and reached deep into people’s lungs, which led to emergency services getting overwhelmed by the number of cases within 30 minutes.

Ambulances couldn’t reach many patients, hospitals were inundated, and emergency rooms saw an eightfold increase in respiratory cases. Tragically, 10 people died, including a 20-year-old student who collapsed on her lawn.

Paul Beggs, an environmental health scientist at Macquarie University, called the incident “unprecedented” and “catastrophic.” Thunderstorm asthma, while still not fully understood, appears to be triggered by downdrafts that stir up grass pollen and spores, sending them into the storm system. Moisture and electric fields in the clouds cause the pollen to rupture, vastly increasing airborne allergens. The resulting cascade can affect even those without a prior history of asthma.

Melbourne has experienced seven major thunderstorm asthma events since 1984, but the phenomenon is not isolated to Australia. Similar cases have occurred in places like Birmingham, UK, and Atlanta, USA. Although still rare, climate change appears to be increasing their likelihood. Rising global temperatures are extending pollen seasons and intensifying storm activity, creating the conditions for more such incidents.

Beyond extreme events, climate change is also worsening seasonal allergies in general. In the US, pollen levels are forecast to exceed historical averages in 39 states this year, and experts warn that this trend will continue. Plants that rely on wind to spread pollen—such as trees, grasses, and weeds—are the primary culprits of hay fever and respiratory allergies. As their seasons grow longer and more intense due to warmer temperatures, more people are suffering from stronger and more prolonged allergic reactions.

Beggs, who published a paper in 2024 linking climate change to thunderstorm asthma, says he is “reasonably certain” that climate change played a role in Melbourne’s 2016 tragedy. “We know that climate change is leading to greater amounts of pollen in the atmosphere,” he said, also noting that it’s altering the types and timing of pollen exposure.

In short, climate change isn’t just a long-term environmental concern—it’s having real, immediate health consequences by fuelling both the intensity and frequency of allergy-related illnesses.

By Nazrin Sadigova