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Heat isn't the only problem coral is facing either. More CO2 in the ocean means higher acidity levels. Agricultural and other land runoff also damages coral. Basically they are getting hit from all sides by humanity.

Even though the ocean is immense, enough carbon dioxide can have a major impact. In the past 200 years alone, ocean water has become 30 percent more acidic—faster than any known change in ocean chemistry in the last 50 million years...
At its core, the issue of ocean acidification is simple chemistry. There are two important things to remember about what happens when carbon dioxide dissolves in seawater. First, the pH of seawater water gets lower as it becomes more acidic. Second, this process binds up carbonate ions and makes them less abundant—ions that corals, oysters, mussels, and many other shelled organisms need to build shells and skeletons.

Well documented by 25 years of AIMS research on the Reef, the increased sediment and nutrient loads to coastal waters:

      * smother coral reef organisms due to the settling of suspended sediment
      * reduce light availability for coral and seagrass photosynthesis due to increased turbidity
      * favour the growth of macroalgae at the expense of corals due to high nutrient availability.

More recent work on contaminants such as agricultural pesticides has demonstrated that several reef foundation species are highly sensitive to acute exposure of herbicides. The potential build-up of contaminants can weaken the health and resilience of corals and other organisms, making them more susceptible to disease outbreaks or climate impacts.

Bleaching isn't a continuous thing, but kind of fluctuates. Take a look here
http://www.aims.gov.au/docs/re...

Each one seems to be getting worse than the previous, so we shouldn't be patting ourselves on the back that this one is over.

Thank you Mr Coward. But while water quality does impact the health of the GBR in a few specific areas, it does not cause bleaching.

This is what AIMS has to say about recent bleaching events:

In 2016, record oceans temperatures have led to record widespread coral bleaching on Australian coral reefs. This bleaching is part of the ongoing third global bleaching event, declared by the National Oceanic and Atmospheric Administration (NOAA) in 2015.

Between February and May, the Great Barrier Reef experienced record warm sea surface temperatures. Extensive field surveys and aerial surveys found bleaching was the most widespread and severe in the Far Northern management area, between Cape York and Port Douglas. Here, bleaching intensity was ‘Severe’ (more than 60% community bleaching). Bleaching intensity decreased along a southerly gradient. While most reefs exhibited some degree of bleaching, this bleaching varied in intensity (from less than 10% to over 90% community bleaching) and was patchy throughout most of the management area.

The impact from this bleaching event, the most widespread and severe ever recorded on the Great Barrier Reef, is still unfolding. Based on in-water monitoring surveys, overall coral mortality is (as of June 2016) at 22% for the entire Great Barrier Reef. Coral mortality is highest in the northern section. Post-bleaching reef monitoring surveys towards the end of the year will provide further clarity on the full extent of coral mortality.

Thank you Mr Coward. But while water quality does impact the health of the GBR in a few specific areas, it does not cause bleaching.

This is what AIMS has to say about recent bleaching events:

In 2016, record oceans temperatures have led to record widespread coral bleaching on Australian coral reefs. This bleaching is part of the ongoing third global bleaching event, declared by the National Oceanic and Atmospheric Administration (NOAA) in 2015.

Between February and May, the Great Barrier Reef experienced record warm sea surface temperatures. Extensive field surveys and aerial surveys found bleaching was the most widespread and severe in the Far Northern management area, between Cape York and Port Douglas. Here, bleaching intensity was ‘Severe’ (more than 60% community bleaching). Bleaching intensity decreased along a southerly gradient. While most reefs exhibited some degree of bleaching, this bleaching varied in intensity (from less than 10% to over 90% community bleaching) and was patchy throughout most of the management area.

The impact from this bleaching event, the most widespread and severe ever recorded on the Great Barrier Reef, is still unfolding. Based on in-water monitoring surveys, overall coral mortality is (as of June 2016) at 22% for the entire Great Barrier Reef. Coral mortality is highest in the northern section. Post-bleaching reef monitoring surveys towards the end of the year will provide further clarity on the full extent of coral mortality.

The Great Barrier Reef has been monitored by AIMS since 1980. The first mass bleaching event occurred in (then) record warm year 1998 when 50 per cent of the reefs suffered bleaching. The next in 2002 where 60 per cent of reefs were affected. In both events, about five per cent of the Great Barrier Reef's coral reefs were severely damaged. (compared to 22% now)

The impact from this most recent bleaching event, the most widespread and severe ever recorded on the Great Barrier Reef, is still unfolding.

There's no ice in Queensland, the prevailing ocean currents go south and are replenished by clean water from the coal sea. However fertilizer runoff has been the barrier reef's #1 enemy for decades. We don't get red-tides so much but the runoff triggers the regular crown of thorns plagues whose larvae eat the algae, then as adults eat the coral. The plagues can and do occur naturally, usually after floods from cyclones. The fertilizer both amplifies and increases the frequency of the plagues to the point were the reef does not have enough time between plagues to fully recover.

The reef's in the Caribbean and mediterranean were already heavily damaged when Jack Cousteau was swimming around taking notes in the 60's. Since then Science has discovered that a healthy reef actually has the majority of its biomass stored in large fish such as sharks, a severely degraded reef has the majority of its biomass stored in small fast growing invertebrates and weeds. The only reason the filthy Ganges river has not destroyed the Seychelles and other pristine reefs nearby is that it's mouth is clogged with thousands of acres of mangroves that act as a natural (and extremely efficient) water filter.

Nearly all marine biologists will tell you the answer to the serious problem of collapsing fisheries is to set aside marine parks in specific locations that would cover approximately 5% of the world's coastline and some specific deep sea ridges, virtually everyone else will say there's "plenty of fish in the sea".

Since I don't actually have all day to reply, here is a quick selection of 'reputable' links and a few recent (05) peer-reviewed journal article abstracts concerning global warming.

I wasn't implying that you should take MY word for it...just that I have experience in this topic and that my (informed) opinion is that GW is underway. Denying global warming is about as futile as denying evolution (I'm also a paleontologist). As I mentioned in the previous post, however, the causes of global warming are still up in the air (although I personally suspect that greenhouse gas emissions play a role in accelerating warming). Of course Fairbanks (Nature 342/89) demonstrated that there was a two meter per century rise in sea level around 14000 years ago, so rapid change can occur even without human influence.

Here are a few references:

Fairbanks, R.G., 1989, A 17,000-year glacio-eustatic sea level record; influence of glacial melting rates on the Younger Dryas event and deep-ocean circulation: Nature, v. 342, no. 6250, p. 637-642.

http://earthobservatory.nasa.gov/Library/Aerosols/
http://www.aims.gov.au/pages/research/coral-bleach ing/scr2000/scr-00gcrmn-report.html
http://www4.nas.edu/onpi/webextra.nsf/44bf87db3095 63a0852566f2006d63bb/e4dcc6e935831fc885256a8400588 146?OpenDocument
http://climatechange.gc.ca/english/default.asp
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From: Analysis of mean, maximum, and minimum temperature in Athens from 1897 to 2001 with emphasis on the last decade, trends, warm events, and cold events, Extreme climatic events

The 105-year (1897-2001) surface air temperature record of the National Observatory of Athens (NOA) has been analyzed to determine indications of significant deviations from long-term average features in the city of Athens. The analysis of the whole record reveals a tendency towards warmer years, with significantly warmer summer and spring periods and slightly warmer winters (an increase of 1.23 and 0.34 degrees C has been observed in the mean summer and mean winter temperature, respectively). The tendency is more pronounced for the summer and spring maximum temperature, but marginal for the minimum temperature of the cold season. On a monthly basis, a statistically significant (at the 95th confidence level) warming trend has been observed in the average maximum temperature of May and June. The trend analysis for the last decade of the record (1992-2001) revealed a significant increase for both warm and cold seasons, yet maximum and minimum temperature. Extreme temperatures (high/low temperatures above/below a certain threshold value) and extreme events (prolonged extreme temperatures) have also been studied. The number of hot days as well as the frequency of occurrence and duration of warm events have significantly increased during the last decade, while a negative trend is observed in the frequency of low temperatures and the duration of cold events especially after 1960.
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From: Recent trends from Canadian permafrost thermal monitoring network sites, Permafrost and Periglacial Processes, vol.16, no.1, pp.19-30, Mar 2005

The Geological Survey of Canada (GSC), in collaboration with other government partners, has been developing and maintaining a network of active-layer and permafrost thermal monitoring sites which contribute to the Canadian Permafrost Monitoring Network and the Global Terrestrial Network for Permafrost. Recent results from the thermal monitoring sites maintained by the GSC and other federal government agencies are presented. These results indicate that the response of permafrost temperature to rec

The referenced article gives few details, but I'm willing to bet that the WetPC beats the SeaPC hands down (literally).

Don't know if it comes with matching trunks
or not, but you can always check out the WetPC
from AIMS, the Australian Institute of Marine Science.

-Justin

Don't know if it comes with matching trunks
or not, but you can always check out the WetPC
from AIMS, the Australian Institute of Marine Science.

-Justin