nature's cry for action on climate change
When Tony Fontes set off from California in 1980 his plan was to travel the world as a back-packing dive instructor. But his first stop was the Whitsundays and that was it. He never left.
“The Great Barrier Reef is the most magic environment on the planet. As a diver you can’t do better. It was, and still is, amazing,” Fontes said.
The newcomer became a keen student of the Reef, soaking up its many nuances. In the summers he noticed that small patches of coral would turn totally white.
“I didn’t really pay much attention to it because in a few weeks they would return to normal,” he said.
That changed forever in 1998. For the first time researchers recorded severe bleaching events on coral reefs in every region of the world. Scientists declared it the first global coral bleaching event. Half the reefs on the Great Barrier Reef were impacted. In the Whitsundays, Fontes felt a growing unease.
“For the first time there was coral that just didn’t come back. It died, was covered in algae, and that was that.
“It was really quite depressing. Coral bleaches and you think ‘yeah it’ll come back’ and then it doesn’t and you realise this is a lot more serious.
“You make a living showing tourists beautiful coral, not dead coral covered in algae.
“Even back then people said it was climate change. You start to think ‘what’s going to happen next summer?’”.
- Tony Fontes
That same year Paul Marshall was at James Cook University.
He and a fellow PhD student heard about the bleaching and headed out onto the Reef to do some research.
“It was one of those life-changing moments,” said Marshall.
“The Great Barrier Reef had always seemed so magnificent and large and unassailable that we thought it was somewhat immune from bleaching.
“I got really focused on gaining a better understanding of what climate change meant for coral reefs,” he said.
In fact in the years ahead Dr Paul Marshall went on to become the founder and Director of the Climate Change Program at the Great Barrier Reef Marine Park Authority.
By 2002, when Australia’s national treasure suffered another mass bleaching event, Paul had started work at GBRMPA. This time he took to the air.
“The bleaching was so widespread and dramatic you could actually survey for bleaching by looking out the window of a plane and picking the white reef,” said Marshall.
“We saw bleaching that spanned two thousand kilometres north to south.
“You get extremely concerned when you see things going wrong at that scale,” Marshall said.
In Australia it has not just been the Great Barrier Reef impacted.
The first mass coral bleaching event ever recorded for Western Australia occurred during the 2010-11 summer.
Reefs from the Montebello and Barrow Islands in the north to Rottnest Island in the south were hit by an underwater heatwave peaking at up to 5°C above long-term averages.
For the first time significant bleaching was recorded at the World Heritage-listed Ningaloo Reef. In one section of Ningaloo, live coral cover crashed from 80% to 6%.
As coral bleaching became an issue of world concern, universities and research institutes strived to learn more.
“Our knowledge of the physiology and biology of coral bleaching has gone forward in leaps and bounds,” said Marshall.
- Dr Paul Marshall
Corals are actually tiny animals called polyps. They live in colonies of hundreds, thousands or even millions of individuals. Hard corals extract chemicals from seawater to create the limestone cups in which they live. Over decades these limestone cups build up to create a reef.
Millions of years ago coral polyps started allowing microscopic algae called zooxanthellae to live inside their cells.
It was a development that enabled corals to thrive. The algae turn sunlight into energy and up to 95% of the nutrients they make are leaked to the coral.
In return, the zooxanthellae have a safe place to live and receive nutrients from the coral’s waste.
However, in certain conditions this mutually beneficial relationship becomes destructive.
When the water is warmer than normal for weeks on end and there is bright sunshine, the algae go into overdrive and can produce toxic levels of oxygen.
As a self-defence mechanism the corals shed the algae. Coral polyps are actually clear, it is the zooxanthellae that give coral its beautiful colour.
Without the zooxanthellae, the coral's bright white skeleton is revealed through its transparent tissue. This is known as bleaching.
If conditions return to normal relatively quickly, corals can regain their zooxanthellae and survive.
But without their zooxanthellae, corals no longer receive enough food. They go into a downward spiral, losing fat and other energy reserves, becoming weak, and susceptible to disease. When bleaching is prolonged, they can die.
When bleaching happens across a whole reef it is known as ‘mass bleaching’ and scientists say global warming caused by burning fossil fuels is behind this disturbing phenomenon.
As Ove Hoegh-Guldberg, Director of the Global Change Institute, wrote in The Conversation: “Climate change has been driving up sea temperatures.
“When natural variability adds to this trend, such as during El Niño, temperatures now exceed the threshold for mass coral bleaching and death.
Hoegh-Guldberg wrote that climate change may be influencing the intensity of El Niños:
The Intergovernmental Panel on Climate Change, the leading international body for the assessment of climate change, states that mass bleaching and coral death “is the most widespread and conspicuous impact of climate change”.
Scientists predict bleaching will become more frequent and severe. Following the first global bleaching event in 1998 it took 12 years before the second global event hit the world’s reefs in 2010.
Then just five years later experts declared the third global coral bleaching event was underway. The National Oceanic and Atmospheric Administration, the U.S. scientific agency which produces global bleaching forecasts, made the announcement in October, 2015.
NOAA said the third global event actually started in mid-2014 in the north Pacific and expanded to the south Pacific and Indian oceans in 2015.
“We may be looking at a 2-to-2½-year-long event. Some areas have already seen bleaching two years in a row.
“Research shows that the frequency of mass bleaching events is increasing because of global warming. The corals are being hit again and again,” Eakin said.
And that’s the biggest concern for Dr Terry Done, formerly the Senior Principal Research Scientist at the Australian Institute of Marine Science.
“Coral communities have a good capacity to bounce back but they need a decade or more between severe impacts.
“If they get clobbered too frequently it’s not just the corals in trouble it’s all the other species which live in, on and among the corals,” Done said.
- Dr Terry Done
There is much at stake. Aside from their natural beauty, coral reefs are extremely valuable ecosystems.
The IPCC reports that coral reefs account for up to 12% of the fish caught in tropical countries, and up to 25% of the fish caught by developing nations.
They protect shorelines from storm surges and cyclones, and more than 100 countries benefit from the tourism and recreational value of their coral reefs.
Scientists believe new medicines are waiting to be discovered from coral reef animals and plants. There is good reason for such optimism. The breakthrough AIDS treatment AZT came from a sea sponge.
While there is now wide acceptance that climate change is causing bleaching that wasn’t the case when Paul Marshall started at GBRMPA.
“It was really hard to talk about bleaching and climate change because politicians don’t want to hear about problems," said Marshall.
“There were some quite clear, if implied, instructions not to talk about climate change. That wasn’t our policy area. We dealt with corals.
“But you can’t really talk about coral bleaching without talking about causes and the biggest cause is climate change.
“So it’s been really interesting to see a shift in the willingness of government staff to talk about the importance of dealing with climate change," Marshall said.
"reducing nutrient and sediment pollution helps corals build resilience to climate change while the world acts to reduce greenhouse gases"
- Dr Paul MarSHALL
One of the turning points was the emergence of a new concept: improving the resilience of the Reef.
“Resilience was a way of understanding that there’s stuff we can do to help the Reef cope with climate change," Marshall said.
“It was a more constructive lens. There were opportunities for action and that gave us a new lease of life in dealing with climate change."
“There was science to back it up. We now know that corals exposed to poor water quality, particularly elevated nutrients, will bleach at a lower temperature.
“These excess nutrients, mostly from agriculture, wash off the land and also cause crown of thorns starfish outbreaks which destroy coral.
“Sediments, made worse by clearing in reef catchments, inhibit the recovery of coral communities.
“So reducing nutrient and sediment pollution helps corals build resilience to climate change while the world acts to reduce greenhouse gases.
“It could be personal action to reduce your own greenhouse gas emissions. It might be having a strong voice in the public and political debate about the need to transition to renewable energy.
“Or if you’re a farmer or fisher or someone who lives on the coast you might be able to reduce pollution flowing to the Reef,” Marshall said.
As for Tony Fontes, he hopes to be a 90-year-old diving on the Reef.
TAKE ACTION: Sign the petitionCut the pollution: keep our coral colourful!
Dear Prime Minister Turnbull;
The Great Barrier Reef is in serious trouble: our corals are starting to turn white. Climate change - driven by the mining and burning of fossil fuel - is warming our oceans and bleaching coral reefs.
If we act now - the coral can recover and the colour will come back.
Commit the Australian government to:
- Turn down the heat: commit now to achieve 100% renewable energy as soon as possible
- Give the Reef a fighting chance: support a legal cap on chemical farm pollution that runs into Reef waters. This pollution makes coral more vulnerable to bleaching and feeds crown of thorns starfish outbreaks.