Assessing Current and Future Ocean Acidification and Climate Vulnerabilities Along the Hawaiian Archipelago

Oceans are Warming

Acknowledgements

This work, “Assessing Current and Future Ocean Acidification and Climate Vulnerabilities Along the Hawaiian Archipelago,” was supported by the NOAA Ocean Acidification Program under grant NOAA-OAR-OAP-2020-2006333.

Principal Investigators

  • Dr. Christopher L. Sabine, University of Hawaiʻi at Mānoa
  • Dr. Kirsten L.L. Oleson, University of Hawaiʻi at Mānoa

Project Teams & Roles

Dynamically Downscaled Regional Projections of Ocean Acidification in the MHI
  • Lucia Hošeková — [Role]
  • Tobias Friedrich — [Role]
  • Brian Powell — [Role]
  • Christopher Sabine — [Role]
  • Guangpeng Liu — [Role]
  • Jacob Gunnarson — [Role]
  • Malte Stuecker — [Role]
Ecosystem Modeling with Atlantis & Spatial Vulnerability Assessment across MHI
  • Lansing Perng — [Role]
  • Mariska Weijerman — [Role]
  • Kirsten Leong — [Role]
  • Lucia Hošeková — [Role]
  • Elizabeth Fulton — Atlantis Developer
The Economic Impact of Climate Change on Coral Reefs in the MHI
  • Ashley Lowe Mackenzie — [Role]
  • Anders Dugstad — [Role]
  • Lansing Perng — [Role]
  • Carlo Fezzi — [Role]

About Our Project

Coral reefs form the backbone of Hawai'i's nearshore ecosystems, supporting high biodiversity and delivering substantial ecological and economic benefits. Although they cover just 0.2% of the seafloor globally, Hawaiian coral reefs account for approximately 85% of all coral reefs in the United States. These ecosystems support about a quarter of all marine species and provide essential services, including fishery habitat, coastal protection, recreation, and tourism. In the Main Hawaiian Islands (MHI), coral reefs generate roughly $800 million per year in value from fishing, recreation, and other activities.

Climate change poses growing threats to Hawai'i's coral reefs. Two primary drivers of risk are rising ocean temperatures and ocean acidification (OA). Warming ocean waters can disrupt the symbiosis between corals and their algae, leading to coral bleaching events. Prolonged or severe bleaching can result in widespread coral mortality. Simultaneously, increased concentrations of atmospheric carbon dioxide (CO₂) are absorbed by the ocean, increasing the concentration of hydrogen ions by about 30% since pre-industrial times and lowering the saturation state of aragonite, a mineral essential for coral skeletons. These changes make it more difficult for corals to grow and maintain their structures and can lead to cascading effects throughout the reef ecosystem and food web.

Assessing reef vulnerability and quantifying ecosystem degradation require spatially explicit analyses that capture both ecological dynamics and community-level impacts. However, much of our understanding comes from global models that fail to capture the fine-scale variability and local oceanographic conditions essential for Hawai‘i, limiting the scientific foundation for effective management and policy decisions.

Our study addresses this gap through integrated modeling. We combine high-resolution projections of OA and temperature with spatially explicit ecosystem modeling that tracks coral, fish, and fishery changes under three climate scenarios. These ecological projections are linked to recreational reef use values, providing an integrated perspective on climate-driven impacts to both marine ecosystems and dependent communities.

Overview Video