The global coral bleaching event, ongoing since 2023 and declared by the International Coral Reef Initiative (ICRI) in April 2025, presents a complex paradox concerning the ocean's capacity to absorb carbon dioxide. Research suggests that the decline of coral reefs, driven by rising ocean temperatures and acidification, may lead to an increased oceanic absorption of atmospheric CO2.
Lester Kwiatkowski from Sorbonne University, along with Alban Planchat and Laurent Bopp, presented research at the EGU General Assembly in Vienna in April 2025. Their models indicate that reduced coral calcification, a process that releases CO2 into seawater, could result in a greater net uptake of carbon by the ocean.
The current global coral bleaching event, the most severe on record, has impacted approximately 84% of the world's reefs between January 2023 and May 2025. This situation underscores the intricate relationship between marine ecosystems and climate change, highlighting the urgent need for measures to protect coral reefs while simultaneously addressing the broader issue of climate change mitigation.