Most of world’s colourful corals go white in record-breaking bleaching

The world’s rainbow reefs have turned ghostly white, signaling the most intense global coral bleaching event ever recorded. According to the International Coral Reef Initiative (ICRI), a staggering 84 per cent of the world’s reefs have been affected by this ongoing crisis. This figure far surpasses previous events, which impacted between 21 to 68 per cent of coral reefs.

Corals, small marine animals that thrive in colonies with colorful symbiotic algae, have been pushed to the brink as ocean temperatures continue to rise. When the water becomes too warm for too long, the algae release harmful compounds, leading the corals to expel them and leaving behind a bleached white skeleton. This process, known as bleaching, has devastated coral reefs around the globe.

The current bleaching event, the fourth since 1998, began in January 2023 and has unfolded in different regions at varying times over the past two years. Record-breaking ocean temperatures have fueled this crisis, culminating in April 2024 when the event was officially declared a global coral bleaching event.

Scientists are deeply concerned about the prolonged nature of this bleaching event, which has now entered uncharted territory. Britta Schaffelke, a researcher at the Australian Institute of Marine Science, emphasized the urgency of the situation, noting that while reefs have shown resilience in the past, the prolonged duration of this event is unprecedented.

Mark Eakin, a coral scientist, expressed uncertainty about when or if the bleaching event will come to an end. The relentless rise in ocean temperatures has raised fears that the heat stress triggering bleaching may not subside, putting the world’s coral reefs at risk of irreversible damage.

Valeria Pizarro, a researcher at the Perry Institute for Marine Science, highlighted the alarming impact of the bleaching event on common coral species in the Caribbean. Nicola Smith, an assistant professor at Concordia University, underscored the broader implications of coral reef loss on marine ecosystems and human populations that rely on these vital habitats.

Despite the grim outlook, there is hope that coral reefs can recover if immediate action is taken to reduce greenhouse gas emissions and implement conservation measures. The ICRI stressed the importance of limiting global temperature rise to safeguard coral reefs and the billions of people who depend on them for sustenance, economic stability, and protection.

While the road ahead is daunting, researchers like Melanie McField believe that corals can still survive if comprehensive strategies are put into place. Efforts such as selective breeding, coral restoration, pollution reduction, and sustainable fishing practices could help mitigate the impact of coral bleaching and pave the way for reef recovery.

As the world grapples with the devastating effects of climate change on coral reefs, urgent action is needed to preserve these diverse ecosystems and the myriad benefits they provide to marine life and human communities. By prioritizing conservation and emission reduction efforts, there is still hope that the world’s rainbow reefs can regain their vibrant colors and ecological vitality.