Harmful bleaching of the world’s coral has now grown to include 84% of the ocean’s reefs in the most intense event of its kind in recorded history. That’s according to the International Coral Reef Initiative. Warming oceans cause corals to expel the colorful algae living inside of them, putting the coral at risk of death. Healthy corals are essential for seafood production, jobs and coastline protection worldwide. Scientists say it’s essential to reduce greenhouse gases that are the main driver of atmospheric warming. Last year was the warmest on record, and much of that heat is going into oceans.