Since the first major bleaching event in 1996, Hawaiian corals have been subject to increasing heat stress and more prevalent bleaching events. New research from oceanographers at the University of Hawai‘i at Mānoa used high-resolution modeling that includes small-scale processes to examine projected heat stress on coral reefs over the 21st century. Comparing this heat stress to previous estimates of the rate at which corals may adapt to changing conditions, the authors found that Hawaiian corals have the possibility of adapting to future heat stress, even under a high emissions scenario. Their results were published recently in Scientific Reports .
“Our research shows that Hawaiian corals may be exposed to unprecedented human-induced heat stress in the coming decades,” said Kate Feloy, lead author of the study, who conducted this work as part of her doctoral research in the Department of Oceanography in the UH Mānoa School of Ocean and Earth Science and Technology (SOEST). “However, our results also provide some surprising hope that Hawaiian corals may be able to adapt to increasing temperatures.”
Feloy and co-authors used high-resolution ocean simulations, run under three different climate emissions scenarios. The modeling approach accounts for small-scale processes and can reveal important spatial patterns in local warming. This is the first time this type of high-resolution climate projections have been used to assess future heat stress around the Main Hawaiian Islands.
Coral reefs have high cultural and economic value and are a critical source of food and coastal protection in Hawai‘i. In order to prepare for a changing climate, it is important to understand how temperatures on Hawaiian reefs are projected to change in the future.
This study provides projected heat stress not just for the region as a whole but examines differences across and between individual islands. The team’s results show that not all coastal locations are projected to experience human-induced climate change at the same rate. They found that corals around Hawaiʻi Island are projected to experience higher heat stress than the other Main Hawaiian Islands.
“The differences in warming are caused by complex ocean dynamics on small spatial scales in the waters around Hawaiʻi,” Feloy shared. “These dynamics change the spatial patterns of human-induced coastal warming. Because of the spatial differences in projected heat stress, the rate at which corals will need to adapt in order to keep pace with increasing temperatures varies around the islands.”
“Our study provides important spatial information that may be useful for local marine management,” said Feloy. “However, it is important to note that this study investigates only temperature and there are many other stressors that also impact Hawaiian corals.”
Human-induced climate change is also leading to overlapping environmental stressors such as episodes of extremely high temperature and acidity and low oxygen concentrations in the water. The research team is also exploring how these overlapping stressors will evolve in the future and how they will affect the marine ecosystem.
Other studies show that corals exposed to variable background temperatures are more resilient to heat stress. Feloy and colleagues are currently investigating how the tides contribute to natural temperature variability around Hawaiian corals.
Scientific Reports
Computational simulation/modeling
Regional dynamics drive differences in future heat stress and reveal where Hawaiian corals are most likely to persist
20-Jul-2026
The authors declare no competing interests.