“There’s no disputing climate change is the number one threat to the Great Barrier Reef. Without a worldwide effort the planet will lose its coral reefs” says Prof Hughes. Hughes is convinced that reoccurring bleaching episodes are the result of climate change that has “been happening for the last 20 years or so, and the Government hasn’t done enough about it”.

Last year, Prof. Hughes and a team of marine scientists made headlines around the world after revealing 90% of the Great Barrier Reef was impacted by coral bleaching.

“It broke my heart to see so many corals dying on northern reefs on the Great Barrier Reef in 2016…With rising temperatures due to global warming, it’s only a matter of time before we see more of these events. A fourth event after only one year is a major blow to the Reef” he adds.

One year on from the last study and unprecedented back-to-back bleaching is sending Terry back out to the Reef. For the next seven days he will carry out aerial surveys to find out to what extent global temperature rises are impacting the Reef.

Prof. Hughes tells the Ecologist, “the message is we have a narrow window of opportunity to save the Great Barrier Reef – but business as usual in greenhouse emissions will be incredibly damaging to it. We’ve already seen three events probably four. The sooner we start to curb greenhouse emissions – Australia as well as every other country – the better for coral reefs not just the Barrier Reef”.

Whilst some commentators believe the Great Barrier Reef is dead, those dedicating their life to researching the Reef are a little more optimistic. Despite four catastrophic bleaching periods, there’s hope a narrow window of opportunity maybe found.

Research shows heat is main cause of bleaching

Hughes, lead author on the most recent paper, Global warming and recurrent mass bleaching of corals, maps the effects of increasing temperature across previous events in 1998, 2002 and 2016. In overlaying three maps from the three years, the research shows how the distinct geographies of the three events is caused by heat exposure.

Last year was incredibly hot in the north and that’s where all the bleaching was; the south was cooled down by a cyclone [Winston] in the nick of time and that saved the bottom half of the Great Barrier Reef from bleaching last year according to Prof.Hughes.

Bleaching – caused by increases in ocean temperatures from global warming – forces corals to eject zooxanthellae algae. Corals need the algae to help photosynthesize and reproduce. Without photosynthesizing the corals turn white, and eventually die. The Reef’s corals are in danger after three and now possibly a fourth bleaching outbreak has created what Professor Hughes sees as a “cumulative footprint off all three events. If you superimpose them the data indicates that more than 90% of the Barrier Reef has now bleached at least once over those three events”.

Prof. Hughes and his team also found that despite politicians throwing money at water quality improvement measures, poor water quality isn’t the major cause of bleaching.

“It’s clear that water quality nearest to the land is muddier than the middle and outer Reefs with their pristine waters a familiar sight in glossy tourism magazines, but building resistance or improving water quality won’t alter the bleaching”.

What’s needed to improve the Barrier Reef is a global intervention. At a local level “it’s not possible to build local resistant to climate change through local management. That’s not to say managing water and fishing is not a good idea as it does affect the reef’s capacity to bounce back” says Hughes.  

Who are the ‘Reefers’ behind the headlines?

Marine scientists are affectional known as ‘reefers’, and one of the biggest fish in the field is distinguished Professor, Terry Hughes FAA.

The most cited individual coral reef scientist in the world, he started working on Caribbean coral reefs in the 1970s. Since gaining his PhD from John Hopkins University, his work continues to reward him with an abundance of accolades. He’s been praised as everything from a “reef sentinel”, to the seminal researcher in the field of coral reef ecology. Growing up in Ireland, Terry studied at Trinity College Dublin, gained his PhD in the USA, and took a postgraduate job at the University of California, Santa Barbara, before moving to Townsville, in northern Australia during the late 1980s.

Hughes is supported by a team of marine scientists who are all based at the Centre for Excellence, including Senior Research Fellow, Dr Andrew Hoey.

Hoey has worked with coral reefs since moving from Sydney to Townsville in 1995. An economics graduate who never worked a day in the field, like every other Australian Andrew has a passion for the outdoors, and moved north to study corals for three years at James Cook University in 1995.

Andrew is also the President of the Australian Coral Reef Society – the oldest organisation in the world concerned with the study and protection of coral reef.

As a Senior Research Fellow at ARCCOE, Andrew’s role in last year’s project was to carry out underwater surveys of bleaching reefs at Lizard Island in the catastrophically damaged northern zone.  

Aerial surveys of the bleaching tell the scientists where the bleaching is occurring but he says to understand the scale, “you really need to get into the water, if you want to document the mortality.”

Hughes and Hoey agree global warming and changes in climate temperatures are responsible for the bleaching. Calling on more to be done by UNESCO and a speeding up of the 2050 Reef Plan will help make the most of the narrow window they have identified to halt the destruction.

Always take the weather with you

Whilst scientists are convinced that climate change is responsible for the bleaching, climate sceptics  think bleaching outbreaks are more likely a combination of natural weather patterns and increased global temperatures. The El Niño, La Niña and ENSO weather patterns circumnavigating the planet that bring warmer weather (El Niño), cooler weather (La Niña) and neutral weather (ENSO).

Prof. Hughes disagrees: “It’s a myth that El Niño contributes to bleaching. In 1998 one of them contributed to a bleaching event on the Barrier Reef. In 2002 the second bleaching event was not an El Niño year; five years later, (2017) we are seeing bleaching and again, it is not an El Niño year”.

Whilst, El Niño gives a slight spike of heat, “the reality is that La Niña years today are now warmer than El Niño years were 20 years, because of global warming” adds Prof. Hughes

Sceptics can no longer say that bleaching isn’t caused by global warming, “It’s us – it’s not El Niño. Blaming the weather is an excuse to say it’s not just us, it’s nature too but in truth it’s anthropogenic global warming”.

Last year was Australia’s fourth recorded hottest year with national temperatures reaching 0.87 °C above average. Ocean temperatures also rose to 0.77°C above average. Sea temperatures on the Great Barrier Reef spiked between February and April the time of corals bleaching.

International pressure could save the Great Barrier Reef.

After almost 40 years working with coral reefs, Prof. Hughes wants UNESCO do more.

UNESCO has until now, held back from listing the Reef as ‘in danger’ because the area has remained relatively pristine.

UNESCO is concerned about whether the attribute of the world heritage area that led to its inscription in 1981 is being maintained. The Outstanding Universal Values – OUV – relate to the northern part of the Barrier Reef, the area that is the most damaged.  

Prof. Hughes explains that before last year bleaching “Australia has argued that the OUV of the world heritage area is still intact, because the northern third is still pristine. That’s where the dugongs (manatee), turtles and corals, were. But, between February and October last year, two thirds of the corals in the northern Great Barrier Reef died. That is a catastrophic loss”.

Without the corals there is no ecosystem, biodiversity or habitat for turtles and dugongs (seacows). Corals are an integral part of the OUV. Without corals there’s no geological structures, no biodiversity, and no aesthetic value – all of which are OUV elements.

Mixed Messages over mines

Convincing UNESCO that mines and coastal development can co-exist with the future security of the Reef is a big task. But, politicians and UNESCO need to be brave enough to face up to the real causes of climate change.  

The Barrier Reef is in Australian waters, and it falls to Federal Minister for the Environment and Energy, Josh Frydenberg, to convince UNESCO the Reef is surviving.

Stewardship of the Barrier Reef is spilt in favour of the Federal Government, with the Queensland Government responsible for a very narrow strip along the coastal edge –  including fisheries, ports and dredging, coastal development and coal mining.

Although much of the responsibility for the Reef’s future survival depends on decisions made over 1,000 miles away in the capital Canberra, both Federal and State governments are united in support for a new Adani mega coal mine to bring economic growth to the area.  

The Professor is forthright in his views on coal, recently Tweeting to Queensland opposition leaders wanting to build a new coal fired power station in north Queensland, “I’m off tomorrow to measure back-to-back bleaching on #GreatBarrierReef. Leave the bloody coal in the ground!”

“Both governments are ‘singing from the same hymn sheets’ when it comes to developing the Adani coal mines, which is a terrible policy failure for the GBR. If the Adani Carmichael mine goes ahead it would make it impossible for Australia to meet its responsibility for the COP21 treaty” warns Prof. Hughes.  

“Australia at least has signed up for the 1.5 degrees centigrade target, which we are currently on a trajectory to miss. Remember these three bleaching events have happened with less than one degree of global average warming. Two degrees will not be comfortable place for corals” he says.

This policy disconnect between Australia’s love of fossil fuels, clean coal, fracking etc.; Queensland’s pledge to have 50% renewable energy, and Australia’s responsibility for stewardship of the world heritage area means advocates need to look in and outside of Australia for support.

Dr Hoey says, “We need to look for a global solution and Australia should be leading the way in discussions of clean coal. Don’t try and badge coal as a clean energy – it’s not a clean energy”.

UNESCO and Australian Government need closer ties.

UNESCO World Heritage Community will meet for its 41st session in Kraków in July, and the annual meeting could provide the narrow window of opportunity needed to save the Reef. But Prof. Hughes is adamant that his role in the future of the Barrier Reef is as a scientist and not a spokesperson or media personality.

“My niche role as a scientist is not to lead the charge on anti-coal or pro-renewable energy or even saving the reef – my role is to get the data and show what is actually happening to the GBR”.

But both Hughes and his colleague Hoey understand that media interviews and publishing papers play a critical role in educating people about the deteriorating health of the Barrier Reef.

Some of the coverage from last year’s bleaching had a tendency to be negative – like a requiem for the Reef. The message that’s getting out via the media is the Barrier Reef is dead and that’s not helpful adds Dr Andrew Hoey.

Terry gets that media reports with negative reporting, disaster discourses or blaming natural weather cycles “are not helpful, [and] the last thing we want to do is write off the Barrier Reef – these bleaching events are incredibly serious”. Instead as Director of the Coral Reef for Excellence, Professor Hughes would like to see more pressure from UNESCO and a fast tracking of the 2050 Reef plan.

More info here:

Integrated Coral Reef Studies,

UNESCO World Heritage Committee will next meet July between 2^nd and 12^th.

Prof. Terry Hughes paper Global warming and recurrent mass bleaching of corals, by 46 co-authors, appears in the journal Nature. http://dx.doi.org/10.1038/nature21707

This Author

Dr. Maxine Newlands is a lecturer in Political Science at James Cook University, and was not paid by the centre for this interview.