We are livin’ in a land down under
Where women glow and men plunder
Can’t you, can’t you hear the thunder?
Then I run then I take cover

— Men At Work – Land Down Under


For the last several years, Australia has been suffering through the unhealthy reality and pubic health consequences of global warming and climate change. Deadly heatwaves, massive wildfires, and paradoxical floods on what is naturally an exceedingly dry continent (where the vast majority of its citizens live in coastal areas); loss of human lives and wildlife; and the bleaching and death of vast expanses (93%) of the Great Barrier Reef have descended, seemingly all at once, on the “Land Down Under.”

The forecast for Australia looks even more grim as extreme weather events and sea level rise continue to impact its citizens while the government elected to serve them sticks its collective head further into the sand. A few weeks ago there was an extreme weather event in Melbourne that took the city, its residents, and medical and public health officials by surprise. Reed Alexander and James Griffiths describe a frightening storm that unleashed respiratory suffering… and panic:

An unusual combination of weather conditions leading to a freak illness known as thunderstorm asthma has left four people dead in Australia.

Thousands of people were rushed to hospital Monday with breathing problems in the southern Australian state of Victoria as emergency services struggled to cope.

Three were still in a critical condition Thursday…

During a four hour period Monday, Ambulance Victoria received more than 1,900 calls, or one call every four to five seconds. An extra 60 ambulances were deployed, as well as police and firefighters.


A large percentage of these calls came from people with no prior history of asthma. Michelle Innis picks up the story:

…They flooded the city’s emergency rooms, swamped ambulance call lines and joined lines around pharmacies during six hours on Nov. 21. All were struggling for breath. About 8,500 people went to hospitals. Eight have died, and one remains in intensive care more than a week after a thunderstorm surged across Melbourne, carrying pollen that strong winds and rain broke into tiny fragments.

So many people became ill so quickly that some of the state’s crisis medical teams were stretched beyond their limits. Firefighters and police officers stepped in where paramedics were overloaded. Triage centers at 10 hospitals struggled with admissions across Melbourne, Australia’s second-largest city, with a population of 4.4 million in the greater metropolitan area and suburbs.

“This was a health emergency of an unprecedented scale,” said Jill Hennessy, the minister for health and ambulance services in Victoria State, announcing a statewide inquiry…


Thunderstorm asthma has happened before:

The world’s first recorded thunderstorm asthma event occurred in Melbourne in 1987, when hospitals reported a five-fold increase in asthma cases. Similar events have happened in the United States, Canada, Britain and Italy. The last major event in Melbourne was in November 2010.


Researchers at Cal Tech explain the meteorological mechanism of action of thunderstorm asthma:

Thunderstorms have often been linked to epidemics of asthma, especially during the grass flowering season; however, the precise mechanisms explaining this phenomenon are unknown. Evidence of high respirable allergen loadings in the air associated with specific meteorologic events combined with an analysis of pollen physiology suggests that rupture of airborne pollen can occur. Strong downdrafts and dry, cold outflows distinguish thunderstorm rain from frontal rain. The weather system of a mature thunderstorm likely entrains grass pollen into the cloud base, where pollen rupture would be enhanced, then transports the respirable-sized fragments of pollen debris to ground level where outflows distribute them ahead of the rain. The conditions occurring at the onset of a thunderstorm might expose susceptible people to a rapid increase in concentrations of pollen allergens in the air that can readily deposit in the lower airways and initiate asthmatic reactions.


Or, stated another way:

Thunderstorm asthma occurs when a storm hits during a period of unusually high rye grass pollen, said Robin Ould, chief executive of the Asthma Foundation of Australia.

“When you have a perfect storm coming together (of) a very high pollen day, high humidity, and a thunderstorm, the grains of rye grass absorb water with the humidity and they break up into thousands of pieces,” Ould said.

“Normally with rye grass the pollen would be trapped by nose hairs. When it breaks up it goes straight to the lungs.”
The pollen irritates the lungs’ bronchial tubes, causing them to become inflamed and filled with mucus and making it hard for people to breathe.

Pollen levels peak in late spring. When this combines with strong winds, rain and high temperatures, as it did in Victoria this week, it can lead to incidents of thunderstorm asthma.


Pediatricians and other primary care providers, pulmonologists, and allergy/asthma/immunology specialists understand that changing weather events — a warm front pushing through, a cold front descending, a line of storms barreling down — provoke health symptoms, especially those involving the respiratory tract, among vulnerable populations, including infants and children, the elderly, and those with asthma, COPD, and other chronic respiratory conditions. Rachael Rettner says fungal spores may be partly responsible:

It’s also thought that gusty winds in thunderstorms help to spread pollen particles and other allergy-inducing substances. A 2008 study that looked at emergency room visits in Atlanta over a 10-year period found that there were 3 percent more visits for asthma on days following thunderstorms. The link between asthma visits and thunderstorms was strongest when the wind gusts during the storm were intermediate to high, the study found.


What we also know is that global warming plays a principle role not only in causing extreme weather events like more powerful thunderstorms, but also by extending the growing season of plants, thus increasing the pollen they produce and exacerbating allergic diseases. In the U.S., for example, ragweed season has been extended by 2-4 weeks, according to the Allergy & Asthma Network. Rising global temperatures also increases ground level ozone levels which, as we’ve discovered previously on The PediaBlog, wreaks havoc on human lung function. Australian doctor Marion Carey tells the Sydney Morning Herald that “we need to do more to understand the impact of climate change on our health”:

With climate change we can expect to see more hot days, heavy rainfall events and severe meteorological events. In fact, our health services are already having to adapt to the health impacts of more and longer heatwaves. Increasing atmospheric carbon dioxide and temperatures are also associated with faster plant growth with more pollen produced by each plant, increases in the amount of allergenic proteins in the pollen, along with earlier and longer pollen seasons.

Last year, the World Allergy Organisation warned climate change was causing changes that can put our respiratory health at risk – more severe and prolonged heat waves, variability in temperature, increased air pollution, forest fires, droughts, and floods. “These changes in climate and air quality have a measurable impact not only on the morbidity but also the mortality of patients with asthma and other respiratory diseases … global warming is expected to affect the start, duration, and intensity of the pollen season on the one hand, and the rate of asthma exacerbations.”