After a study last month revealed that the Great Barrier Reef was suffering a coral bleaching event for the second consecutive year, scientists have completed an aerial survey of the reef offering more evidence of the environmental catastrophe that is currently taking place.
Before this year there had been three major bleaching events identified in the modern history of the reef - 1998, 2002 and 2016. Researchers last month identified the signs of another bleaching event taking place this year, but it wasn't until the visual surveys were completed that the situation could be definitively confirmed.
The same scientists who undertook observations in 2016 recently completed an aerial survey of the reef covering more than 8,000 km (5,000 mi), examining 800 individual coral reefs. The survey identified new patches of bleaching across the middle third of the reef, an area previously undamaged in the 2016 event.
The back-to-back bleaching events, and the increased spread south of the damage now leaves only the southern third of the reef untouched, and while bleached coral doesn't necessarily mean the coral is dead, the dual impact of these losses decreases the reef's natural ability to repair itself.
"It takes at least a decade for a full recovery of even the fastest growing corals, so mass bleaching events 12 months apart offers zero prospect of recovery for reefs that were damaged in 2016," explained Dr James Kerry, who was part of the recent aerial surveys.
In tandem with this new bleaching event, a 100-km (62-mi) corridor of the reef was recently damaged by Tropical Cyclone Debbie in late March. Despite the cyclone potentially offering a cooling effect that could have mitigated the ongoing bleaching, the researchers noted that the damage caused by the violent weather pattern rendered any positive effects negligible.
"Clearly the reef is struggling with multiple impacts," explains Professor Terry Hughes, who undertook the recent surveys with Dr James Kerry. "Without a doubt the most pressing of these is global warming. As temperatures continue to rise the corals will experience more and more of these events: 1° C (1.8° F) of warming so far has already caused four events in the past 19 years."
The scientists noted that this year's mass bleaching seems to be occurring without the assistance of El Nino weather patterns, which highlights the impact of global warming and general sea temperature rises as the primary culprit.
Source: ARC Centre of Excellence for Coral Reef Studies
Furthermore, bleaching of the exposed coral, left out to dry by receding sea levels doesn't really offer any indication of the overall reef health. Unexposed coral is likely fine. But this should be checked. Can't do it from the air, though. They'll have to get down there and start investigating personally.
Finally, citing climate change as some type of culprit for the warming of the shallow reef water is really tiresome. The specific heat capacities of water and air basically ensure that there's no physical mechanism by which the air can heat the water (this is not a static system the can eventually reach equilibrium). The upper xx meters of the ocean is heated by direct sunlight not by conductive heat transfer from air to water. Nor is it heated by the long wave infrared back radiation postulated from CO2. Infrared radiation will heat the top few millimeters of the ocean at best (probably more like the top few microns) which will quickly evaporate. It's actually quite a complex interchange, which is poorly understood and not even a part of the GCMs (AFAIK).
So, again, per a recent comment I made, this is all pretty easy stuff that doesn't require a genius level intellect to think through. The more I read about this stuff, the more I question the whole climate change narrative. When something is blamed for everything, it sounds more like a political tool than actual science.
rip
Once a reef dies... the fish move on. See Jacque Cousteau's film in which he revisits reefs that once flourished and were dead upon his return. Yes there are a few fish that hang around but overall it's like a lush forest turned desert. Corals are fickle... they are barometer's in the same manor amphibians are to changes, problems, pollution, be them man made or natural.
In short, of the reefs die, it makes a huge impact on the food chain in the ocean. Combine that with natural and a high human consumption rates... well... to add up where this is going, it's kindergarten math.
There have been recent studies which confirm this.
So while bleaching is often blamed on CO2, greenhouse warming, and "acidification", there are other less esoteric causes which are right in front of us which have largely been ignored, especially in the press.
In fact, shallower seas are indeed being found along most of the GBR, and the sea level has become lowest precisely in those areas where the bleaching is strongest.
https://wattsupwiththat.com/2017/04/05/falling-sea-level-the-critical-factor-in-2016-great-barrier-reef-bleaching/
The data clearly support this.