Coral reefs are creeping away from the tropics in response to warming oceans, but the pace is too slow to beat the heat and escape impacts of climate change, according to a breakthrough study published June 6 in Science Advances . The study, authored by researchers at University of Hawaiʻi at Mānoa's Hawaiʻi Institute of Marine Biology (HIMB) Marine Ecological Theory Lab, also offers a hopeful alternative: immediate actions to reduce greenhouse gas emissions can significantly improve the future outlook for coral reefs globally.
"As the ocean warms, species tend to move poleward," said lead author Noam Vogt-Vincent, a National Oceanic and Atmospheric Association (NOAA) climate and global change postdoctoral fellow at HIMB's Marine Ecological Theory Lab and lead author of the study. "We know from the fossil record that coral reefs have previously expanded their ranges in response to past climate change, but we didn't know whether this was a matter of decades or millennia."
Supercomputer simulation models
To predict changes in coral reef distributions, the team turned to sophisticated simulation models run on Koa, UH's high-performance computing cluster. The team designed a global model that included roughly 50,000 coral reef sites, incorporating processes essential to coral reef health, such as how corals grow, disperse, evolve and adapt to heat stress. They tested three future emissions scenarios: low warming (~2℃ by 2100), moderate warming (~3℃) and high warming (>4℃).
"By modeling coral reefs globally and incorporating evolution and connectivity, this study provides an unprecedented long-term view of how these complex ecosystems will respond to climate change," said HIMB Assistant Research Professor and Vogt-Vincent's postdoctoral advisor Lisa McManus.
"We discovered that it takes centuries for tropical-type coral reefs to expand significantly beyond their current distribution," Vogt-Vincent said. "Unfortunately, while we've confirmed that coral reef range expansion will indeed eventually occur, the biggest coral losses are expected in the next 60 years, meaning these new, higher-latitude reefs won't form fast enough to save most tropical coral species."
Places such as northern Florida, southern Australia and southern Japan might eventually see new reefs, but not soon enough to help corals survive the 21st century.
Hope remains for coral reefs
The study showed that significant cuts in greenhouse gas emissions, including those outlined in the Paris Climate Agreement, could dramatically reduce coral loss. Instead of losing up to 86% of coral reefs, losses could be limited to around a third.
"Our study suggests that reductions in greenhouse gas emissions will not just improve coral reef futures this century, but for hundreds to thousands of years into the future," Vogt-Vincent said. "Our actions over the next few decades will therefore have incredibly long-lasting consequences for coral reefs globally."
HIMB's Marine Ecological Theory Lab will continue to use supercomputer power to better understand the threats and possible solutions for coral reefs around the world.
This research was funded by NOAA through University Corporation for Atmospheric Research's Cooperative Programs for the Advancement of Earth System Science. The project was led by Vogt-Vincent under the supervision of McManus, with contributions from James Pringle (University of New Hampshire) and Chris Cornwall (Victoria University of Wellington).
For the entire story, visit the HIMB website .
The post Urgent action needed to protect corals fleeing warming seas first appeared on University of Hawaiʻi System News .
