Fourth Global Mass Coral Bleaching Event | 20 Apr 2024

Source: DTE

Coral Reef Watch (CRW) of the United States and the International Coral Reef Initiative (ICRI) have confirmed the fourth global mass coral bleaching event in 2023-2024.

This is the second such event in the last 10 years and comes at a time when global oceans have also recorded unprecedented heat in 2023 and 2024.
The El Nino conditions in the equatorial Pacific Ocean added onto the general trend of warming over land and oceans.
- During El Niño events, warm ocean currents from the central and eastern Pacific Ocean move towards the western Pacific, causing sea surface temperatures to rise in many regions.
Among long-term patterns, ocean heating and mass coral bleaching are closely tied to the occurrence of El Nino events.
- This warming effect of El Niño contributes to ocean heating, which stresses coral reefs.
The various factors responsible for coral bleaching are increasing sea surface temperatures, extensive marine heatwaves, ocean acidification and pollution.
When sea surface temperatures and ocean heat in general rise, the algae on the hard corals die off. This makes the corals white.
This process is known as ‘coral bleaching’. Once bleached, the corals can become vulnerable to diseases and eventually die.