Coral reef bleaching has become a large issue in recent years. Notably, 2023 to 2025 saw the worst amount of coral reef bleaching in recorded history.
From 2023 to 2025 heat stress impacted around 84.4% of the world’s coral reefs. With that the average coral cover (amount of coral reef existent) dropped from 39.8% to 30%. This signifies that there has been a spike in ocean temperature and acidity as well that causes coral reef bleaching. This year the ocean heat content, globally, reached a record high which was 0.49 degrees celsius above what it was from 1981 to 2010. The causes for a rise in ocean temperature are things such as greenhouse gasses, which are types of gasses that trap heat in the atmosphere, like carbon dioxide. They are emitted from human activities like burning fossil fuels (coal or petroleum) and deforestation. Ocean acidification has breached planetary boundaries, meaning essentially Earth’s life support is at risk. This signals a shift in ocean chemistry as a whole.
Coral reefs are a crucial part of the ocean. They provide shelter and food for many different ocean animals such as butterflyfish which eat coral, fusiliers, hawkfish and many other types of fish. Sea birds and other large predators, like sharks, need coral reefs as well. They find prey that hide in the coral. Coral reef bleaching leads to devastation for ocean biomes. It kills corals and destroys habitats for a quarter of all marine life. Without coral reefs the ocean will lose its biodiversity and disrupt the food chain for predators.
This has become a bigger issue than ever before. Many different ocean lifeforms are seeing rapid decline. This effect heavily threatens fisheries and global stability.
