Hawai‘i will be under increasing risk of flooding and other damaging storm impacts as climate change shifts the historical pattern of hurricane tracks and raises the ocean level to make the islands more vulnerable, according to a study led by researchers at the Department of Ocean and Resources Engineering (ORE) .
A team of researchers, led by professor Kwok Fai Cheung and lead author Ning Li, mapped future hurricane flooding from storm surge and waves on top of the projected sea level rise. While the study didn’t find a significant increase in the number of cyclones, the data did show that hurricanes that historically pass to the south of the islands will instead approach closer to Hawai‘i with more landfalls.
The maps show substantial hurricane flooding across large sections of O‘ahu’s South Shore, including parts of Waikiki, Kaka‘ako, Honolulu Harbor and downtown, and Daniel K. Inouye International Airport. “Most of the flooding in Waikiki does not come directly from the ocean, but via the Ala Wai Canal,” Cheung said.
Historically, tropical cyclones traveling from the Eastern Pacific to the Central Pacific weaken and move to the south when approaching the Hawaiian Islands due to a high- pressure system to the northeast, strong wind shear and relatively cool waters. But this study indicates those conditions are unlikely to be prevalent toward the end of the century.
“Nowadays they all seem to be moving closer to the islands,” said Cheung, who has lived in Hawai‘i for 25 years. “In the last few years, we’ve had several major storm events approaching the Hawaiian Islands from the east, so we already feel a change in the pattern.”
Cheung said Hawaii may have gotten a glimpse of the future in 2015, when powerful El Niño conditions warmed ocean waters around the islands and helped to fuel 15 cyclones in the Central Pacific — roughly triple the basin’s average. The study joins a growing body of scientific evidence suggesting that climate change will bring greater impacts from hurricanes in the coming decades.