---
title: "El Niño Event Sparks Warning for Great Barrier Reef"
url: https://newscentral.site/el-nino-event-sparks-warning-for-great-barrier-reef/
language: en
publisher: "News Central Site"
section: "Science"
published: 2026-10-08T13:00:00.000Z
updated: 2026-10-08T17:42:09.079Z
id: 84725a25-4aa3-4bdf-bfe0-1f9e291e9788
source: "New Scientist https://www.newscientist.com/article/2592422-record-el-nino-threatens-great-barrier-reef-with-ecological-shift/?utm_campaign=RSS|NSNS&utm_content=home&utm_medium=RSS&utm_source=NSNS"
attribution: "Link to https://newscentral.site/el-nino-event-sparks-warning-for-great-barrier-reef/ and name News Central Site when you quote or summarize this story."
---

# El Niño Event Sparks Warning for Great Barrier Reef

Scientists warn that a potentially record-breaking El Niño event in the Pacific Ocean may lead to large areas of the Great Barrier Reef dominated by seaweed instead of coral due to rising water temperatures.

A potentially record-breaking El Niño event in the Pacific Ocean has sparked warnings from scientists about a major ecological shift that could see large areas of the Great Barrier Reef dominated by seaweed instead of coral.

The phenomenon occurs when warmer ocean waters accumulate in the eastern and central Pacific during an El Niño event, disrupting the usual patterns of monsoon troughs and low-pressure zones that bring cooling clouds and rain to the region.

This has been a hallmark of past severe coral-bleaching events on the Great Barrier Reef, including the devastating mortality experienced in 2024.

Coral bleaching occurs when water temperatures become too high for corals to tolerate, causing them to eject the algae that live within their tissues and provide them with food. This leaves corals vulnerable to starvation and death unless waters cool quickly.

Ocean temperatures have risen so much that coral bleaching is now occurring even during neutral and La Niña periods, which normally bring cooler weather to the reef, says marine biologist David Schoeman at the University of the Sunshine Coast.

The frequency of severe heat events has increased in recent years, with six major warming episodes occurring over the past decade alone.

As a result, even when there is some recovery between these extreme weather events, coral reefs are still struggling to bounce back from the damage caused by the frequent and intense warm-ups. The more often this happens, the greater the impact on coral health and the harder it becomes for them to recover.

Some areas of the Great Barrier Reef could be pushed beyond a point of no return if another large-scale warming event occurs in the coming months. This would mean that these sections of the reef might transition from being dominated by coral to becoming an algal-dominated system, marking a fundamental shift in the ecosystem's dynamics.

Reverting back to a coral-dominated state once algae takes over is not a simple matter of returning to normal temperatures. It requires significant changes to the environment and could be extremely difficult to achieve.

Record global ocean temperatures are combining with the current El Niño event to create an unprecedented level of heat stress for the Great Barrier Reef, according to experts at the Australian Institute of Marine Science.

The Great Barrier Reef's coral cover has been declining steadily since 1998, when about 8% of the reefs experienced severe bleaching. By 2016, this rate had increased to around 35%, but the damage was largely confined to the reef's northern regions.

However, a significant shift occurred in 2024, with widespread bleaching and mortality affecting not just the far north, but the entire reef system. Approximately 60% of corals across potentially 40% of the reef were affected by bleaching, resulting in severe damage in many areas.

Even remote locations like the Swains Reefs, which are situated 150 kilometers offshore and surrounded by normally cool deep waters, experienced significant coral death. In these areas, between 70 and 90% of corals perished, shattering previous assumptions about their resilience to bleaching events.

The recent breakdown in a natural cooling process that usually protects the reefs has exacerbated the situation, leading experts to warn of an expanding "spatial footprint of severe heat stress and bleaching. As a result, organisations are preparing for extensive surveys to quantify the extent of the damage caused by the current El Niño event.

Organisations are now focusing on assessing the damage caused by the current El Niño event, which is expected to have a significant impact on marine ecosystems worldwide.

Research into marine cloud brightening, a potential tool for mitigating the effects of climate change, has hit a snag. While this method shows promise in artificially brightening clouds and reducing sunlight, it won't be available for deployment until 2028. Scientists are working on implementing this technology to protect vulnerable areas like the Great Barrier Reef.

Studies have shown that marine cloud brightening can increase the number of droplets in clouds by up to several hundred percent, and human aerosol interventions can significantly impact ecosystems. However, research also suggests that large reductions in sulphur dioxide emissions from shipping have increased the risk of coral bleaching, despite reducing air pollution. This highlights the complexity of managing marine ecosystems.

Daniel Harrison, a researcher at Southern Cross University in Australia, is leading efforts to consult with communities and implement marine cloud brightening in the Great Barrier Reef region. According to Harrison, his team's experiments have shown that clouds can be artificially brightened, but he acknowledges that further work is needed before this technology can be deployed on a large scale.

The Great Barrier Reef faces an unprecedented threat from a record El Niño event that could push it beyond a tipping point of ecological collapse. To mitigate this disaster, researchers have proposed a multi-faceted approach combining marine cloud brightening with the introduction of heat-tolerant corals and controlling crown-of-thorns starfish populations.

Modelling suggests that this strategy has potential to be particularly effective when implemented together, allowing scientists to buy time" for the reef while efforts to reduce emissions are ramped up. This is not a substitute for addressing climate change through renewable energy and emissions reduction, but rather a temporary measure to stabilize the ecosystem until more sustainable solutions can be achieved.

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Source: [New Scientist](https://www.newscientist.com/article/2592422-record-el-nino-threatens-great-barrier-reef-with-ecological-shift/?utm_campaign=RSS|NSNS&utm_content=home&utm_medium=RSS&utm_source=NSNS)  
Published by News Central Site: https://newscentral.site/el-nino-event-sparks-warning-for-great-barrier-reef/