Ruined homes and other structures are among the most obvious signs of bushfires, and because there are insurance and rebuilding costs attached to them they’re often front of mind when it comes to the hard-dollar estimates of a fire’s cost.
Not as obvious are the accumulated health costs created by a bushfire’s visible signature: smoke.
The intensity and wide distribution of smoke from wildfire plumes was an added feature of the last Australian fire season, during which more than eight million hectares – much of it eucalyptus forest – was burnt out in about six months.
Now, a team led by the University of Tasmania’s Fay Johnston has examined the wildfire-smoke-related health costs for the most recent 20 fire seasons and put the figure for the 2019-20 bushfires at $1.95 billion.
This is substantially above the next highest – $566 million in 2002-03 – and more than nine times the $211 million median annual wildfire costs for 2000-01 to 2018-19.
The 2019-20 estimate is supercharged by an estimated 429 smoke-related premature deaths, 3230 hospital admissions for cardiovascular and respiratory disorders and 1523 emergency attendances for asthma.
“During the 2019–20 fire season, the most densely populated regions of Australia, especially those along the eastern seaboard, were affected by extreme air pollution for periods ranging from weeks to months,” the researchers write in a paper in the journal Nature Sustainability.
“Fire smoke is a complex and dynamic mix composed of particulate matter and a range of gases, such as nitrogen dioxide, carbon monoxide, volatile organic compounds and poly-cyclic aromatic hydrocarbons.”
The authors note that wildfire smoke is known to cause a substantial health burden given the well-established associations between particulate matter less than 2.5 microns in diameter (PM2.5) and admissions to hospital and premature mortality, particularly for cardiovascular and respiratory conditions.
Their estimates are based on a limited range of outcomes for which the air pollution and health risk effect estimates have been well established. The analysis did not include many other well-established health outcomes of population exposure to smoke, including increases in symptoms, medication use, primary health care attendances and ambulance callouts, reduced productivity or the mental health burden, or premature mortality associated with the contribution of the wildfire smoke to increased annual average air pollution.
For these reasons, they write, “the health and economic assessments we present are likely to underestimate the true burden”.
That is a point picked up by a number of experts asked to comment on the findings.
“The actual costs will be much higher as the future health events which are not known were not included in this study,” says Brian Oliver, who leads the Respiratory Molecular Pathogenesis Group at the University of Technology Sydney and the Woolcock Institute.
“As a country what this means for us is that if we have more bushfire events of the magnitude which was experienced in 2019-20 the health and economic costs will affect everyone in Australia, through either higher taxes or direct health effects.”
Paul Read, from the Monash Sustainability Institute, says the paper is a critical step in clarifying an important issue with wide-ranging implications, but “it’s not the full story and I dare say hardly the full cost”.
“Past studies suggest you can roughly double the amount of tangible costs to include social and economic multipliers, but even these don’t take into account the long-term costs to families and children as governments borrow against their future to clean up, and borrow against their future to avoid tackling climate change,” he says.
“Once these are included, plus species extinctions, the true costs are immeasurable.”