Poor air quality, health care delays and a surge in suicides have been blamed for hundreds of deaths following large-scale bushfires in Los Angeles and Hawaii.
That's according to three separate reports released this week by the scientific journal JAMA.
The number of suicide and overdose deaths in Hawaii jumped by 46 per cent in August 2023, when fires spread across the island of Maui, according to one report.
Those fires burned more than 2,200 structures and killed more than 100 people directly.
Lung problems and mental health issues also increased following the disaster, according to separate research.
A third paper looking into the Los Angeles wildfires in January found 440 deaths — compared to the official death toll of 30 — could be attributed to the destruction.
Researchers from Boston University's Department of Global Health compared the expected weekly death rate for LA to the actual tally.
They found the additional deaths likely reflected a combination of factors, including "increased exposure to poor air quality" and health care delays.
Weekly deaths 'consistently exceeded' expectations in wake of LA fires
The Palisades fire in California sparked up during heavy winds on January 7, ripping through the affluent LA neighbourhood.
It killed at least 12 people and damaged nearly 8,000 homes, businesses and other structures.
The same day, a second fire started in the eastern suburb of Altadena, killing another 17 and destroying or damaging more than 10,000 buildings.
Other fires ignited across the area in the following days and weeks.
The new study out of Boston University looked at the excess deaths in Los Angeles County from January 5 to February 1.
For each week, they compared the expected deaths and the actual number of deaths in the area.
The weekly deaths "consistently exceeded" the expected amount — with a total 6,371 deaths in that time compared to the expected 5,931.
This meant, they concluded, an excess of 440 people died during the wildfires.
"These additional deaths likely reflect a combination of poor air quality and health care delays and interruptions," the report said.
"The findings … highlight the need for improved mortality surveillance during and after wildfire emergencies."
[research]Co-author Dr Andrew Stokes said researchers had suspected the official death toll after the fires was likely a "severe under-count".
"We used an excess mortality modelling framework to obtain estimates of the wildfires on all-cause mortality," he said.
"[This included] deaths associated with exposure to toxic chemicals in wildfire smoke and deaths associated with health care interruptions and delays.
"These gaps are commonly found in research comparing mortality estimates to official death tolls associated with natural disasters.
"Many deaths from disasters go uncounted, especially when they occur in the weeks and months that follow."
He added future research should investigate additional cause of death data, hospital records and administrative claims to narrow down the specific reasons for extra deaths.
Hawaii fires took a mental and physical toll on residents
In August 2023, a series of wildfires broke out across the island of Maui in Hawaii.
Like the Los Angeles fires, these were sparked by dry conditions and extreme winds.
Four separate fires burned for weeks across the area, killing at least 102 people and destroying thousands of homes.
In the wake of the fire there was also an increase in calls to Hawaii's suicide and crisis helpline, according to research out of New York University.
There were 13 deaths from overdose and suicide in Maui in August 2023, and 59 in non-Maui counties of Hawaii, the highest in a 120-month time period and a 46 per cent increase on all other months.
The jump in numbers was not sustained throughout the following four months.
"Results show that the 2023 Maui wildfires had immediate effects on suicide and overdose deaths in Maui and across the Hawaiian islands broadly," the report said.
"[The statewide rate] suggests that direct exposure to the wildfires may have increased risk of suicide and overdose death among Maui residents who migrated to neighbouring islands during or after the fires.
"Indirect exposure to the wildfires [like] concerns for loved ones may have also increased the risk of death from these causes on neighbouring islands."
Their report noted however that only four months of post-wildfire death data was available, adding their findings were limited by lack of information on exact dates of death and migration data.
The research was supported by the National Institute on Minority Health and Health Disparities.
The second Maui report found there was an increase in economic hardship, food insecurity, and lack of healthcare in the wake of the fires.
[healthcare]Almost a quarter of the 1,043 people surveyed by researchers at the University of Hawaii were experiencing very low food security.
This was more than double the pre-disaster rate.
"Nearly half … reported persistent respiratory symptoms, and living within the fire perimeter was associated with both higher odds of reporting these symptoms and lower measured lung function," the report said.
"Mental health burdens were also substantial, with depressive symptoms exceeding historical pre-wildfire estimates.
"Pre-wildfire mental health prevalence in Maui County indicated baseline depression rates of 30 per cent, low self-esteem prevalence of 13 per cent, and suicidal ideation in less than 1 per cent of the population."
The survey found 4.6 per cent of participants experienced suicidal ideation, 26.1 per cent reported low self-esteem and 49.4 per cent showed "clinically meaningful depressive symptoms".
Their report was backed by the Hawaii Community Foundation, Kaiser Permanente, the State of Hawaii and a grant from the National Institute of Health.
All three reports published by JAMA were peer-reviewed.
'The long tail of disasters' and what it means for Australia
Andrew Gissing, chief executive of Natural Hazards Research Australia, said the reports were important, but not surprising.
"What you're seeing in terms of those excess death statistics, we've seen that here in Australia as well," he told the ABC.
"Post-Black Summer, there's been some similar research done [which found] there were excess fatalities due to wildfire smoke in the hundreds.
"The implication for wildfire management across the world is that as much as we concentrate on the actual fighting of these fires, we need to make sure that we're very much focused on the public health impacts there as well.
"That messaging to stay indoors, to minimise exposure to bushfire smoke [is] obviously really key during these events."
The research about ongoing mental health impacts, he said, could be attributed to the "long tail of disasters".
"We often measure disasters by their direct impact, insurance losses or how many people immediately were injured or killed," he said.
"What we see are these longer tail impacts due to the trauma and the physical impacts of those events."
Dr Sonia Angell, from the Hopkins Bloomberg School of Public Health said the research highlighted the failure of current responses to extreme weather events.
"Each of these studies provides a unique example of how [emergency] health measurements … such as direct fatalities do not sufficiently capture the full health impact of wildfires," she said.
"The work presented here underscores that health effects from wildfires are not discrete nor are they limited to the event."
"Climate health impacts can occur long after an event or be unassociated with extreme events."
The Australasian Fire and Emergency Services Authorities Council (AFAC) said in its latest bushfire outlook there was an "unseasonable bushfire risk" this winter.
The council noted a heightened risk of fire in large parts of Victoria and in southern areas of South Australia.
"[There's] this concept of worsening natural hazard risk that we're facing in Australia," Mr Gissing said.
"That's been driven by climate change increasing the frequency of extremes, but it's also due to our own decisions about where we choose to live and build our homes into the future as well.
"That means we're seeing some people being more frequently exposed [to disasters] than others, particularly in those high-risk areas.
"And with each extreme, we know the compounding trauma of that only makes things worse.'
