Official death count of 2023 Hawaii wildfires doesn’t capture true toll, study suggests

In August 2023, the deadliest fires the U.S. had seen in a century tore through Lāhainā, Maui, devastating the town and taking the lives of between 100 and 102 people, according to an official death count at the time — and, as the planet warms and the climate changes, scientists expect wildfires to grow in number.

Now, two years after those tragic Lāhainā wildfires, researchers have taken a closer look at the true mortality rate associated with the disaster by examining “excess deaths” in the region. This is a measure of the number of deaths that exceeded what’s called the “baseline,” or the number of deaths to be expected in a given region from any cause, not just wildfires.

The team found that all-cause mortality increased by 67% during the month of the fires. This is a big deal because it suggests the true toll of the fire is much larger than what was captured in official counts. The study’s authors think the rise was largely due to indirect deaths not caused by the blaze itself, but rather factors like chronic health conditions being exacerbated or someone facing a disruption in their ability to access medical care.

The authors say their findings put a finer point on the need to find better emergency preparedness, access to medical care and ecological solutions to prevent future tragedies in communities as global warming, primarily driven by human activities like burning coal, continues to increase the severity of natural disasters. This is particularly true for Hawaii, where new developments and tourism demands on the land may have made it more vulnerable to wildfires.

“Native Hawaiians, for the centuries preceding colonization, had ways of stewarding the land so that there were built in mechanisms to mitigate climate crises and effects from potential wildfires,” Michelle Nakatsuka, co-author of the study and medical student at NYU Grossman School of Medicine, told Space.com.

Her paper corroborates other recent research, which suggests the public health impact of the Maui fires are greater than what our health-tracking systems are able to initially catch. A separate study published in August in JAMA, for example, linked the Maui fires to lingering respiratory problems and mental health problems like depression. As natural disasters become more common, studying not just the direct mortality rate but a medical system’s ability to absorb an increased burden of non-fatal health effects becomes imperative.

Why ‘indirect’ death numbers from wildfire are harder to find

Indirect deaths are typically missing from official death counts of disasters including wildfires, because they refer to people dying from causes not as easily attributed to the disaster itself, which mean getting caught in the fire or dying later at a hospital from wounds.

JAMA research on last winter’s Los Angeles fires, for example, found that while there were 30 direct fatalities reported from the fires, more than 400 more deaths may be linked back to the disaster due to factors like poor air quality and disruptions in health care. Smoke from wildfires, for example, may be especially harmful for people with pre-existing conditions that affect the lungs. Heat waves, which have been named the deadliest form of natural disaster in the U.S., also affect people unevenly. Similar to the groups most at risk when the need to evacuate other disasters arise, people with lower mobility, older adults, very young children and people with certain existing health conditions are the most vulnerable to high temperatures.

Looking beyond direct deaths and instead at measures such as excess mortality may provide a more layered view on how wildfires or other natural disasters affect a particular community.

“What this shows really is that the impact of wildfires extends beyond the official deaths that are reported,” Nakatsuka said. “And there’s more insight that can be gained, I think, by looking at both direct and indirect deaths as can be captured by all-cause excess mortality.”

Local solutions for a global climate problems

One problem potentially plaguing Maui and the Hawaiian islands’ responses to natural disasters is a turn away from older, pre-colonial systems that may naturally be better suited to help prevent the spread of fires, according to Nakatsuka and the others of the Frontiers paper. These systems have to do with the layout of the land.

“They had a lot of what’s called ‘green breaks,’ so ways to keep the land wet and resilient,” Nakatsuka explained. This includes fish ponds (loko i’a) and other wetlands Nakatsuka said would help break up fires, should they occur.

Water diversion and the way the resource is also a factor, according to Nakatsuka. While the process looks different today, and much is diverted to more modern structures like shopping malls, water diversion in places such as Maui used to be laid out naturally flowing from the mountains to the ocean in land division called ahupuaʻa.

“It was basically these sort of pie slices that ran from the mountain to the ocean,” Nakatsuka said. “And so in each slice of land, you sort of had everything a community would need to keep themselves alive.”

What’s more, removing invasive, more flammable grasses from the Hawaiian islands may also be an important step.

“Invasive grasses have been found to be actually more flammable than a lot of endemic species,” Nakatsuka said. “Especially given their square square footage, you would expect them to be a lot less flammable than they actually are.”

Importantly, looking for local-level ways to improve resilience to disaster involves bringing local leaders to the table. Indigenous solutions are not only not only culturally relevant, Nakatsuka said, but “in addition, very scientifically sound.

“I think by really allowing indigenous people to participate in policy decisions, we set ourselves up to protect our communities better,” she said.

“These are the people who have been stewarding the land well for centuries before colonization happened, and know how to keep the people and the land healthy.”

A study about these results was published this month in the journal Frontiers in Climate.