The Maui Wildfires Can Be Traced to a Few Familiar Culprits

On the night of August 8th, one of the deadliest wildfires in U.S. history broke out near the Maui town of Lahaina, rapidly engulfing thousands of homes and killing over 100 people, a number expected to rise. Crews are still in the process of locating victims and assessing the full scope of the damage.

How could a lush tropical island be threatened by a disaster that commonly plagues drought-stricken regions? Scientists believe the Maui wildfires can be traced to several environmental factors: native flora’s lack of fire resiliency, the warming climate, and changes to the island’s ecology that occurred during western colonization, among others. Today, the percentage of land in Hawaii burned by wildfires every year is on par with that of the continental Western U.S., around 0.5 percent. But the specific ways in which the changing climate has primed Hawaii for fire, and the challenges faced by local officials on the islands, are unique.

One fundamental difference is that wildfire is historically rare on the islands, says Abby Frazier, a professor at Clark University who researches Hawaii’s ecosystems. “There isn’t the natural historical fire regime in Hawaii that exists in other parts of the world,” said Frazier. Species in Western U.S. forests like the thick-barked ponderosa pine or manzanita plants, whose seeds are released in extreme heat, are well-adapted to wildfires of moderate intensity. Those fires keep the ecosystem healthy, making prescribed burns a viable tool for land managers to help prevent extreme fires. In Hawaii, though, the plants and animals haven’t evolved to withstand the flames. Planned burns aren’t an option—and moderate intensity fires wipe out the native flora and fauna.

“Our native ecology is devastated by fire,” Elizabeth Pickett, co-executive director of Hawaii Wildfire Management Organization, told the Verge. “It doesn’t regenerate. We lose it permanently. We lose the seed bank; the soil is burnt. With each fire that we have, our fire risk actually grows, and we lose our native ecology.” Instead, what comes back are invasive, fire-prone species like non-native grasses, which Pickett, Frazier, and other researchers believe are fueling Hawaiian fires.

Today, enormous sections of Maui, Oahu, and other Hawaiian islands are covered by non-native grass, which Frazier describes as “giant areas that are primed for fire.” Many of these open spaces were once pineapple and sugarcane plantations, a product of 19th century colonization. When the plantations shut down, the land sprouted grass—it now covers over a quarter of the land in Hawaii, and abuts homes and other infrastructure. The grass burns, and when conditions are dry, all it takes is wind and a spark to set off a catastrophic blaze.

In 2018 and 2019, the Hawaii Wildfire Management Organization published a risk assessment document for the state. Lahaina was among a few areas designated as “highest concern” for fire, due to the abundance of non-native grasses and above-ground power lines near the town.

When the fires started on August 8, western Maui was being battered by high winds from Hurricane Dora, which was 500 miles away. Large tropical storms often blow past Hawaii in August, and it’s hard to determine whether climate change is to blame for individual extreme weather events. Still, scientists have warned that the warming oceans and atmosphere will increase the severity of tropical storms. Hawaiian officials believe that downed power lines from Hawaiian electric, knocked over by the 60- to 80-mile per hour gusts, generated the initial spark.

The island was also experiencing flash drought conditions, which occur when a quick onset of hot weather sucks moisture from plants and the soil. Research suggests these dry snaps are becoming more common as average global temperatures rise. The warm, dry spell that preceded the fires on Maui was the latest in a recent history of climate change-driven drought on the Hawaiian islands.

Hawaii’s governor, Josh Green, acknowledged the role the changing climate likely played in Lahaina during a live streamed address on Facebook. “That level of destruction in a fire hurricane—something new to us in this age of global warming—was the ultimate reason so many people perished,” he said.

For Frazier, the fact that wildfires are not native to the ecosystem is a surprising source of optimism. Most of the fires on the islands are human-caused, and the main fuel is an invasive plant that could be contained—which means they have a clear path towards reducing wildfire risk. “We don’t have control over when a hurricane passes by, but the fuels part, these grasses, we actually do have some control over,” she said.

Hawaii may be famous for its tropical rainforests and waterfalls, but Frazier hopes the Maui wildfire helps the wider population develop a more nuanced understanding of the islands’ ecology, and of the challenges facing its natural resources. “It will take resources and action if we’re going to protect these beautiful ecosystems,” said Frazier.