2026 may be the year when coral reefs around the world finally collapse as human–caused climate change continues to warm the oceans.
Over the last 10 years, an estimated 30 to 50 per cent of the world’s coral reefs have already been destroyed.
Now, an expert warns that the world may be teetering on the edge of an irreversible ‘tipping point’ for the planet’s coral population.
Dr Samantha Garrard, a marine ecosystem expert from Plymouth Marine Laboratory, says that the losses over the next 12 months could be ‘catastrophic’.
She warned that the fate of the world’s coral reefs may depend on a cycle of warm and cool waters in the Pacific Ocean, known as the El Niño–Southern Oscillation.
We have just emerged from a ‘devastating’ El Niño cycle, during which warm waters pushed 84 per cent of the world’s reefs into a ‘bleaching–level’ of heat exposure.
With another El Niño cycle expected in 2026, climate scientists are now concerned that coral reefs may not recover from the next blow.
‘The question is whether this will be the year a global tipping point is reached for warm–water coral – a point beyond which their fate is sealed, and even the most resilient species can no longer recover,’ Dr Garrard wrote on The Conversation.
An expert has warned that 2026 could be the year that the world’s coral reefs irreversibly collapse due to humanity’s effect on the environment. Pictured: Turtles swim over bleached coral in the Southern Great Barrier Reef
Coral reefs cover just one per cent of the ocean surface and yet support around a quarter of all marine species.
However, these incredible habitats are also uniquely sensitive to the impacts of human–caused climate change.
When coral becomes too warm, it undergoes a process called bleaching.
The stress of excess heating causes the coral to expel the colourful algae that live inside its tissue, turning it white.
If the hot temperatures last too long, coral can die in huge mass bleaching events, which the reef might never recover from.
Human emissions of greenhouse gases have raised global ocean temperatures to record highs, which makes extreme ocean heatwaves significantly more intense and frequent.
The warmer average temperature also makes coral more sensitive to the influence of the El Niño–Southern Oscillation.
During an El Niño, ocean surface temperatures in the Pacific Ocean rise by at least 0.5°C (0.9°F) above average for months at a time, causing warmer weather all over the world.
Human–caused climate change has increased average ocean temperatures, made ocean heatwaves more likely, and intensified the impact of the El Niño–Southern Oscillation. Now, an expert says this could spell the end for Earth’s coral. Pictured: Elkhorn coral in Key Largo, Florida, killed by a summer heatwave
In the past, warm El Niño years would be followed by years of cooler weather during the so–called La Niña phase of the Pacific Ocean cycle.
Dr Garrard explains that this would give reefs a few years to ‘breathe’ and recover from the stress.
However, research has shown that climate change is making warm El Niños more intense and more frequent, while the transition periods are getting shorter and warmer.
Dr Garrard says: ‘With another El Niño expected in 2026, only a short time after the last one, many reefs will not have had sufficient time to recover.
‘This next phase could trigger widespread coral reef collapse.’
The concern is now that 2026 will be a ‘tipping point’ for the world’s coral reefs, meaning that they would have passed a level of disruption where ecosystem change becomes sudden and hard to reverse.
Last year the second Global Tipping Points report, written by 160 scientists from 23 countries, warned that coral reefs had already passed their thermal tipping point.
The researchers warned that, at temperatures 1.2°C (2.16°F) above the pre–industrial average, repeated mass bleaching events become unavoidable.
In the last decade, the world has already lost between 30 and 50 per cent of all coral reefs as mass bleaching events become more common. Pictured: Dead reef in Western Australia’s Kimberley region following a mass bleaching event
Climate change is making warm El Niños more intense and more frequent, while the transition periods are getting shorter and warmer. This means coral reefs, like the Great Barrier Reef (pictured), do not have enough time to recover
With global warming now at 1.4°C (2.52°F), this tipping point has now been passed, and there is a 99 per cent chance that any coral reefs of meaningful scale will be lost.
Many reefs around the world, including two vital reefs in Florida, have already passed the point of no return and are now on an unavoidable decline toward extinction.
Dr Garrard says: ‘Reaching a simultaneous global tipping point for all corals in 2026 is an unlikely worst–case scenario. But at a local level, many warm–water coral reefs are clearly set to fare badly.’
However, she added that it might not be too late to save at least some of the world’s coral.
Some coral populations, such as those in the Gulf of Aqaba near Egypt and those in Madagascar, have proven to be especially heat resilient.
Likewise, reefs in deeper water offshore might be able to survive for longer thanks to a blanket of cool, dense water.
But if urgent action is not taken to remove some of the pressure facing coral reefs, even these hardy populations are likely doomed.
‘To help these biodiversity powerhouses survive the 21st century, we must do three things: aggressively cut carbon emissions to cool the water, reduce local stressors like pollution or overfishing, and incorporate selective breeding of heat–tolerant corals into restoration plans to improve resilience to heatwaves,’ Dr Garrard concluded.
WHAT IS THE EL NINO PHENOMENON IN THE PACIFIC OCEAN?
El Niño and La Niña are the warm and cool phases (respectively) of a recurring climate phenomenon across the tropical Pacific – the El Niño-Southern Oscillation, or ‘ENSO’ for short.
The pattern can shift back and forth irregularly every two to seven years, and each phase triggers predictable disruptions of temperature, winds and precipitation.
These changes disrupt air movement and affect global climate.
ENSO has three phases it can be:
- El Niño: A warming of the ocean surface, or above-average sea surface temperatures (SST), in the central and eastern tropical Pacific Ocean. Over Indonesia, rainfall becomes reduced while rainfall increases over the tropical Pacific Ocean. The low-level surface winds, which normally blow from east to west along the equator, instead weaken or, in some cases, start blowing the other direction from west to east.
- La Niña: A cooling of the ocean surface, or below-average sea surface temperatures (SST), in the central and eastern tropical Pacific Ocean. Over Indonesia, rainfall tends to increase while rainfall decreases over the central tropical Pacific Ocean. The normal easterly winds along the equator become even stronger.
- Neutral: Neither El Niño or La Niña. Often tropical Pacific SSTs are generally close to average.
Maps showing the most commonly experienced impacts related to El Niño (‘warm episode,’ top) and La Niña (‘cold episode,’ bottom) during the period December to February, when both phenomena tend to be at their strongest
Source: Climate.gov
