Even to the untrained eye, it鈥檚 easy to see that the Great Barrier Reef is in more than a little hot water.
As I board my charter flight from Cairns bound for the remote scientific research station on Lizard Island, I mentally prepare myself for devastating scenes.
Climbing steeply, we bank sharply to the right 鈥� and soon the tropical green of Queensland鈥檚 northern coast is replaced by a startlingly bright turquoise sea.
Advertisement
It doesn鈥檛 take long for my fears to be realised. I look down at an opalescent sea awash with white. Reefs that were once among the world鈥檚 most unspoiled now languish under a baking sky, every one seemingly bleached.
My pilot turns and gives me a thumbs down, shaking his head sombrely.
Worst on record
This is the worst bleaching event the Great Barrier Reef has ever seen, according to , director at the ARC Centre of Excellence for Coral Reef Studies in Townsville, Queensland.
Bleaching happens when corals become stressed and expel algae called zooxanthellae living inside them. These colourful algae provide up to 90 per cent of the energy needs of corals through photosynthesis. Corals can survive bleaching, but will die if they stay in that condition for long enough.
This year鈥檚 bleaching has been linked to the strongest El Ni帽o event on record and climate change, both of which are driving up ocean temperatures here.
鈥淥ne of the impacts of El Ni帽o here in Australia is a weaker monsoon,鈥� says , manager of climate-change prediction services at the Australian Bureau of Meteorology. 鈥淔or the reef, that means less cloud and more sunny days.鈥�
This puts more heat stress on corals, leading to bleaching, which has been getting progressively worse.
鈥淚t鈥檚 already very clear that what we are seeing here is much greater than back in 2002, which in turn was greater than 1998,鈥� says Hughes.
He lays the blame firmly at the door of climate change. 鈥淭he baseline of sea temperature is going up decade by decade due to global warming. When an El Ni帽o event comes along, it adds an extra spike to that rising baseline. We鈥檝e always had those spikes, but before global warming they didn鈥檛 cause the damage that they do now.鈥�
Bad signs
This is my first visit to the reef, and it鈥檚 not looking good鈥� at all.
Home to of fish, 411 types of hard coral and a third of the world鈥檚 soft coral, the reef is the largest living structure on the planet.
Its sheer magnitude makes the reality of surveying it neither quick nor simple: it covers an area bigger than the UK, the Netherlands and Switzerland combined.
Hughes first focused his aerial surveys on the reef鈥檚 northernmost section, which was the hardest-hit area. He concluded recently that 95 per cent of it had been 鈥渟everely bleached鈥�.
鈥淚t was the saddest research trip of my life,鈥� says Hughes, who is yet to find a southern boundary to the bleaching.
鈥淚nitially I thought we鈥檇 only have to survey the most northern part,鈥� he says. 鈥淚t鈥檚 clear though that this bleaching is much more extensive than we thought.鈥�
In 2002, just 18 per cent of reefs in the Great Barrier Reef 鈥� 120 in total 鈥� were severely bleached. This year, well over 500 reefs have been affected so far. 鈥淭his is much more severe than anything we have seen before,鈥� says Hughes.
It could be another six to eight weeks before we get a full picture of how much coral has been lost.
Researchers are keen to find out how multiple bleaching events are affecting the corals.
It takes around 10 years for faster-growing corals to recover from bad bleaching, says of the University of Queensland in Brisbane. 鈥淲e could be getting close to a scenario where the return time for bleaching is actually shorter than the recovery period, and that would be a recipe for ever-declining coral cover.鈥�
Among the corals
On Lizard Island, the research station lies a stone鈥檚 throw from the shortest landing strip I鈥檝e ever seen. I鈥檓 picked up in a classic 1990s white land cruiser and 10 minutes later, after bumping along a short sandy track, I arrive at the research station, which provides accommodation, dive boats, laboratories, a full aquarium and scuba equipment.
鈥淭he amount of coral being affected by this year鈥檚 bleaching is mind-boggling,鈥� says Lyle Vail, one of the station directors. 鈥淵ou see corals that you鈥檙e familiar with, have swum with and that you know individually, and now they are dying.鈥�
And he says that with soft corals, which lack the skeleton of hard corals, only bare rock is left once they鈥檙e gone. 鈥淵ou鈥檇 never even know they were there. It鈥檚 devastating,鈥� he says.
I dive alongside a team of documentary film-makers, among once-pristine coral that鈥檚 now dying before our eyes. A single word is enough to describe our emotions as we head back to base: heartbreak.
It鈥檚 hard to imagine how the reef 鈥� held up as a bastion for those around the world 鈥� can fully bounce back. The hope for many of the scientists is that this event will at least communicate to a global audience the reality of climate change and the effects it鈥檚 having on the natural world.
鈥淐oral cover on the Great Barrier Reef could look very different 10 years from now,鈥� says Hoegh-Guldberg. He highlights that 50 per cent of its coral cover has been lost in the past 30 years and predicts a further decline of 20 per cent if we continue on this path.
鈥淚f we don鈥檛 take aggressive action on climate change over the next decade, it will essentially mean the end of coral-dominated paradises like the Great Barrier Reef and intact coral reefs across the world,鈥� he says.
Read more: Coral comeback: Reefs have secret weapon against climate change; Mission implausible: Extreme schemes to save the reefs
