Ove Hoegh-Guldberg and Tyrone Ridgway in an article at The Conversation identify that "The bleaching is currently focused on the pristine reefs north of Cooktown, driven by water temperatures that have persisted at 1.0-1.5℃ above seasonal averages since mid to late January 2016, and calm and still weather conditions over recent weeks."
In a media release by the Great Barrier Reef Marine Park Authority, Chairman Dr Russell Reichelt said the area around Lizard Island, situated 250 kilometres north of Cairns, and sites further north, had fared the worst.
“This is the result of sea surface temperatures climbing as high as 33 degrees Celsius during February,” Dr Reichelt said. “In the far north, the surveys found severe bleaching on inshore reefs, along with moderate bleaching on mid-shelf reefs. Further south in the Marine Park, mid-shelf and outer reefs that were surveyed are generally displaying minor to moderate bleaching, some of which is typical for this time of year. At this stage, coral mortality also remains low and has only been detected on a small number of reefs.”
In a further media release on 20 March the Great Barrier Reef Marine Park Authority announced that it had lifted its response to level three category (meaning severe regional bleaching), the highest level in its coral bleaching response plan. The statement says that the Australian Government’s Reef 2050 plan is focussed on improving the Great Barrier Reef’s health and resilience so it’s better able to withstand threats to its future, specifically citing the need for culling of crown-of-thorns starfish and reduction in land run-off improving water quality.
Yet the biggest challenge the reef faces comes from the greenhouse gases emitted from coal and other fossil fuels, and the mining and extraction of coal and CSG in Queensland. These are contributing to increasing sea surface temperatures and ocean acidification. During El Nino events water temperatures are further affected that can produce marine heatwaves that bleach the corals. If the heat is extensive enough the corals are unable to recover and subsequently die.
In a tweet on 28 March Professor Terry Hughes from James Cook University offered criticism of the official 2050 reef plan: "Australia's 2050 Plan to 'save the Reef' ignores #climatechange, will be funded by offsets from new #coal mines."
Report from Lizard Island
Bleached staghorn and damsel fish. Photo Copyright by J Rummer
Senior Research Fellow, Dr Jodie Rummer from the ARC Centre of Excellence for Coral Reef Studies has just returned from spending more than a month at Lizard Island Research Station in the Northern Great Barrier Reef. She described the the extent of the bleaching as appalling in a media release on 21st March from the Coral Reef Studies COE.
“I witnessed a sight underwater that no marine biologist, and no person with a love and appreciation for the natural world for that matter, wants to see,” she said.
“The bleaching now is not just restricted to the hard corals. There’s also extensive bleaching in the soft corals, and it is also affecting anemones and giant clams.”
Dr Rummer labelled the coral bleaching event as “catastrophic”. While fish were still in abundant numbers, the bleaching and death of corals will have a knock on effect on other species.
“We know that many of these tropical populations of reef fishes cannot tolerate dramatic increases in temperatures for extended periods of time. So it may be just a matter of time before the fish start feeling the heat as well. We’re watching them closely.” Bureau of Meteorology SST forecasts project that temperatures will remain well above average through March to May before cooling a lttle for winter months (although still likely to be above average).
The marine heatwave follows on from cyclones that also have damaged the northern Reef said Dr Rummer.
“This year, the combination of El Niño, climate change, and an extended period of hot summer days when the tide was exceptionally low has caused many of the corals that survived last year’s cyclone to lose their symbiotic algae and start bleaching.” Dr Rummer said.
Aerial survey finds Massive coral bleaching on northern reef
Surveys of the extent of the coral bleaching damage have recently been conducted by Professor Terry Hughes from James Cook University. They paint a bleak devastation for the northern reef up to and including the Torres Strait. Read the story in the Guardian on aerial survey reveals extent of coral bleaching.
You can watch ABC 7.30 Report on the results of the survey which found that 95 per cent of the reefs in the northern section are now severely bleached. This is the more pristine part of the reef, and so could be expected to have more resilience. Even so, Terry Hughes estimated that due to the extreme nature of the bleaching event, up to 50 per cent of the coral is likely to die. "This will change the Great Barrier Reef forever," Professor Hughes told 7.30 Report.
Professor Justin Marshall, a reef scientist from the University of Queensland, was also interviewed for the 7.30 report program. No beating about the bush, "What we're seeing now is unequivocally to do with climate change," he told 7.30 report. "The world has agreed, this is climate change, we're seeing climate change play out across our reefs."
This is the third major coral bleaching event for the Great Barrier Reef, the first was in 1998 and the second in 2002. If coral polyps survive a marine heatwave they can bounce back, but this can take up to 10 years.
Professor Hughes expressed anger at the inaction of succeeding Australian governments that have effectively allowed this destruction to happen to one of the natural wonders of the world.
"The government has not been listening to us for the past 20 years," Hughes said. "It has been inevitable that this bleaching event would happen, and now it has. We need to join the global community in reducing greenhouse gas emissions."
"For me, personally, it was devastating to look out of the chopper window and see reef after reef destroyed by bleaching. But really the emotion is not so much sadness as anger. I'm really angry that the government isn't listening to us, to the evidence we've been providing to them since 1998." Hughes told the 7.30 Report.
On Day 3 of the survey Terry Hughes identified that of 400 reefs scored before lunchtime, only four had no bleaching.
We have known for a few years that Global Warming imperils coral reefs: 2 degrees warming is too hot, and that Coral Reefs and Ocean Biodiversity threatened by Climate Change.
Marine scientists have been calling for strong action for many years. In 2007 50 Australian marine scientists issued a public consensus declaration on Coral Reef Futures.
Professor Ove Hoegh-Guldberg detailed in a side event at COP15 in Copenhagen, "Carbon and coral reef ecosystems are not sustainable at temperatures that increase up to 2 degrees above the pre-industrial or concentrations of CO2 above 450ppm." he told the audience of climate negotiators and others. "Eliminating these habitats will inevitably lead to about 10 to 20% of marine biodiversity going extinct. Thats all those organisms that are highly dependant on coral reefs. And losing coral reefs will have enormous issues for 500 million people living in approximately 90 nations."
Controlled experiments at the Lizard Island research station and research conducted near volcanic vents at Milne Bay reveal coral reefs are in peril in a high CO2 world. We are already experiencing global average temperatures in excess of 1 degrees C in January and February. Another 0.7 degrees warminig is already built in because of the inertia in the climate system.
Minister for the Environment fiddles with water quality and approving coal mines
media release of an increase in funding of $58 million for a suite of measures to build the health and resilience of the iconic Great Barrier Reef. These revolved around reducing erosion losses and improving water quality. Another $4.86m was allocated on 2 March 2016 for five organisations to work with landholders to address the issue of gully erosion in the Great Barrier Reef catchments.
On March 20, 2016 Greg Hunt announced Australian Government "financial and logistical support for new research into coral bleaching events impacting the Great Barrier Reef."
This will focus on 40 sites in the Far Northern section of the Reef that were surveyed in 2012. Repeat surveys at 30 of these sites were undertaken by the Global Change Institute following Tropical Cyclone Ita. The survey at the 40 sites will be conducted in September 2016 with the Australian Government funding the provision of a suitable vessel and associated costs associated with data analysis and interpretation.
Never mind that Queensland has had substantial land clearing that has contributed significant Greenhouse gas emissions as well as significant erosion and sediment loss. In October 2015 Greg Hunt gave approval to the Carmichael Coal Mine and Rail Infrastructure project. Development of this one mine would be a disaster for the Great Barrier Reef both in direct and indirect impacts.
We are well on the way to exceeding 2 degrees of warming unless we start rapid emissions reduction and energy transition. A good place to start would be to stop digging new coal mines or extending existing ones. A study by Ekin and McGlade published January 2015 into fossil fuel resources and the 2 degree limit found that, without any Carbon Capture and Storage, 88 per cent of coal needs to stay in the ground, unburnt.