Ten Years Ago, Alarm Bells Would Have Rung. Today, Yawn.

Face it, we're becoming acclimated to environmental collapse.  "It's happening, so what?"  Especially when we learn of it in some distant, as in out of earshot, range.

A case in point, the Great Barrier Reef.   This heralded Wonder of the World has now lost fully half its legendary coral cover.   The culprits - acidified ocean waters, storms and swarms of coral-eating starfish.

At present rates of decline, the coral cover will halve again within a decade, though scientists said the reef could recover if the crown-of-thorns starfish can be brought under control and, longer term, global carbon dioxide emissions are reduced.

...Coral reefs are an important part of the marine ecosystem as sources of food and as protection for young fish. They are under threat around the world from the effects of bleaching, due to rising ocean temperatures, and increasing acidification of the oceans, which reduces the corals' ability to build their calcium carbonate structures.

The Great Barrier Reef is the most iconic coral reef in the world, listed as a Unesco world heritage site and the source of $A5bn (£3.2bn) a year to the Australian economy through tourism. The observations of its decline are based on more than 2,000 surveys of 214 reefs between 1985 and 2012.
  
...Two-thirds of the coral loss has occurred since 1998 and the rate of decline has increased in recent years, averaging around 1.45% a year since 2006. "If the trend continued, coral cover could halve again by 2022," said Peter Doherty, a research fellow at the institute.

David Curnick, marine and freshwater programme co-ordinator at the Zoological Society of London, said many of the most endangered coral species around the world were also under severe pressure from the aquarium trade.

"Corals are notoriously hard to propagate in captivity and therefore the trade is still heavily dependent on harvesting from the wild."

He said the results of the Great Barrier Reef survey were not surprising and the challenge for conservationists was to limit the localised threats to give reefs a chance to recover and develop resilience against the effects of climate change. "This is challenging but entirely achievable and there are many community-led projects around the world demonstrating this."

Corals can recover if given the chance. But this is slow – in the absence of cyclones, Cots [starfish] and bleaching, the Great Barrier Reef can regrow at a rate of 2.85% a year, the scientists wrote. Removing the Cots problem alone would allow coral cover to increase at 0.89% a year.

Reducing Cots means improving water quality around the rivers at the northern end of the reef to reduce agricultural run-off – high levels of nutrients flowing off the land feed and allow high survival of Cots larvae. Another option is some form of biological control of populations – Gunn said there were promising results from research on naturally occurring pathogens that could keep Cots in check, but it was not ready to be applied in the field.

He said the future of the Reef lay partly in human hands. "We can achieve better water quality, we can tackle the challenge of crown-of-thorns, and we can continue to work to ensure the resilience of the reef to climate change is enhanced. However, its future also lies with the global response to reducing carbon dioxide emissions. The coral decline revealed by this study – shocking as it is – has happened before the most severe impacts of ocean warming and acidification associated with climate change have kicked in, so we undoubtedly have more challenges ahead."

How will Australia respond?   Agricultural runoff is feeding the exploding populations of starfish, a problem being experienced in other parts of the world also.   And, as for carbon emissions, Australia is on the verge of a massive increase in its coal exports to China that critics warn all but ensures our grandkids will face warming of 6C or more.   If the threat to the Great Barrier Reef isn't a wake-up call to the Australian government, and there's no sign that it is, then don't expect the rest of the world to fret much about it and what it means either.