Coral reefs are vital to the Earth’s ecosystem. Although they cover less than 1% of the ocean floor, they are home to about a quarter of all known marine species, according to US space agency Nasa. But in the last decade, rising temperatures have put coral reef health at risk.
Now, a new study has shown that coral reefs in one part of the Pacific Ocean might have adjusted to higher ocean temperatures, indicating a sort of climate resistance.
Coral reefs have been consistently under threat of disappearance as global temperatures are increasing. A 2018 report by the IPCC (Intergovernmental Panel on Climate Change) concluded that at 2ºC (3.6°F) or more, 99% of all coral reefs could be lost. In 2022, a study published in Nature Scientific Reports offered a glimmer of hope, showing that “within limits, it seems, some corals can acclimate to a warmer world," according to National Geographic.
Now, a new study, led by researchers from Newcastle University, has focused on the Pacific Island nation of Palau. The findings of this study indicate a groundbreaking increase in temperature tolerance among coral reefs. Resistance to higher temperatures would lead to a decrease in future bleaching, an impact of climate change, thus saving the coral reefs, according to a press statement by Newcastle University.
“Our study indicates the presence of an ecological resilience to climate change, yet also highlights the need to fulfil Paris Agreement commitments to effectively preserve coral reefs,” Liam Lachs, the study's lead author, said in the statement.
The results reiterate that the severity of coral bleaching is linked to carbon emissions reductions. High-frequency bleaching can be reduced at some reefs where emissions are low-to-middle. However, some bleaching impacts are inevitable in places where people depend on fossil fuels.
“We quantified a natural increase in coral thermal tolerance over decadal time scales which can be directly compared to the rate of ocean warming. While our work offers a glimmer of hope, it also emphasises the need for continued action on reducing carbon emissions to mitigate climate change and secure a future for these vital ecosystems,” Lachs explained in the statement.
The results provide a glimmer of hope that coral reefs can build resilience with increasing temperatures. “This study shows the potential for some coral reefs to become more resilient to future climate change-fuelled heat waves,” Professor Simon Donner, who collaborated with the lead author, said in the statement. However, Donner acknowledged that this resilience can also come at a cost, such as a reduction in reef diversity and growth.
Donner also emphasised that without significant cuts in greenhouse gas emissions, the reefs in the Pacific won’t be able to provide resources that people in the area have depended on for centuries.