Re: @Alan Brown:
I'm sorry, mate, you need to start paying proper attention. Parrotting a subset of meme sheets then sneering at fantasy-people-in-your-head doesn't cut it.
For a jaw-dropping example, you state you are completely unaware of all the apocalyptic pronouncements re, yes, corals being unable to form their homes. Due to ocean acidification due to rising atmospheric CO2. You're unaware of this?, that's fine (if...utterly bizarre if you've paid any attention at all to the topic)(implying that you haven't but just ran to your meme sheets to find out what to say), but it's a very good idea not to hop in and insist that because you know nothing about it, that everyone else is stupid and narrow-minded and an arrogant foolish pawn of socialmeeja.
Now, you are attempting to panic about bleaching. But then demonstrate that you know nothing about it other than what you've found to copy-paste.
You're clearly unaware of the absolute debacle of AIMS, JCU etc trying to beat up drama about the catastrophic apocalyptic bleaching of Australia's Great Barrier Reef, for example. Which brought to light spectacular incompetence (their survey methodology) but also extensive deliberate lying. Hint: most times anyone checked their surveyed bleached areas, they were found to be unbleached, but that they looked bleached from the air if travelling overhead in an aeroplane (which is how they do the surveys). Hint: the same bleaching was found in 1930 when scientists first looked in-large -- ~45yrs before AGW started (they blamed farmers). Hint: and again the next time they looked in the mid-1960s -- decade before AGW (big global cooling at the time, actually) and this time they blamed crown-of-thorns starfish. Latterly, they've jumped on the AGW bandwagon (AND the farmers again) because there's a LOT more money in it. To create the drama, they've had to hide a whole lot of data. (If you had ever looked at AGW "science", you would immediately recognise that trick -- pioneered by the CRU and used to great effect.) And also they had to lie about the new data. They acknowledged this in a Senate investigation, btw -- do feel free to look into it. Might be time to start doing some genuine reading rather than confining yourself to approved religious propaganda.
Amusingly, when the UN bodies paid attention to their screaming and drama, and announced they were going to pull the reef's UN Heritage status and impose penalties etc because it was being destroyed, the "scientists" (AIMS, JCU, etc) flipped 180° and admitted they'd been bullshitting. This got drilled into in the Senate.
Can bleaching occur? Yes. Absolutely. It happens a lot. Always has. It requires a very very specific and very transient/unstable combination of atmospheric conditions (completely stationary, for a start), wave conditions, and drought onshore. Basically, if onshore has a drought, then an uncommon and transient combination of offshore conditions can bleach surface coral. And they start regenerating immediately the winds start again, and very quickly if the rains come, on land. The biggest problem researchers have in practice with bleaching is finding enough of it that's heat-created to justify nontrivial work on it. Try talking to them -- I have. One of them described the necessary atmospheric conditions as "almost lensing", btw, to give you an idea of how unusual.
Is bleaching unusual in the greater scheme of things? The 340,000+ square kilometres greater scheme of things? Well, Captain Cook reported seeing large areas bleached in the 1700s (not a lot of AGW back then). And it's been a consistent theme amongst people living on those coasts ever since -- every so often, chunks get bleached. I personally first heard a tourist complaining about seeing bleaching in the early 70s. Pre-AGW, to be clear. So, no, it's not unusual across a region nearly 3 times bigger than England. It's just a normal thing.
Now, even by AIMS' own data, their big bleaching drama coupla years ago was a debacle, as their maps quietly showed that the previous year's "catastrophic" bleaching had completely recovered the following year, which itself showed "catastrophic" bleaching but all in different areas. The 2 areas together would mean that, according to you, the vast majority of the Great Barrier Reef was dead.
So what _actually_ happened? In real life? Well, AIMS had to cough up actual data to the Senate. They'd been publicly and internationally banging the drama drum about the catastrophic loss of reef over the last decade, and that it didn't have long to live unless Urgent Crisis Action!. But upon the _actual_ data being extracted from them, it was discovered that :
* the Northern region hadn't changed,
* the Central region had more than doubled,
* the Southern region had tripled.
All during a period of --according to Gavin and Phil via GISS & HadCruT-- soaring global warming.
Now, really, anyone sane would have absolutely expected it to be fine re temperatures, because that reef has happily survived the Mediaeval Warm Period (hotter than 2100's worst case per IPCC) ~a thousand years ago, the Roman Warm Period (much hotter than today) ~2 thousand years ago, and the wotchamacallit Warm Period (Mesopotamian, it's on the tip of my tongue) which was profoundly hotter than 2100's worst-case prediction: anyone banging the drama drum re temperature carnage is clearly an idiot.
The most "at-risk" reef in the world as "temperature soars", is actually growing. Growing quite a bit.
The Great Barrier Reef is clearly a denialist.
I'm a trained researcher, btw, read research for fun, and I discovered in 2004 to my extreme shock and complete inversion of beliefs-up-to-that-point that the entire body of AGW rests on fraudulent foundations. I've not yet found any honest work supporting it. Please don't parrot religious memes at me and expect to be taken seriously -- do some work. Here's a simple exercise to get you started: a renewable "proof" hosing down a "false" theory -- took me around 30secs to discover it fraudulent. See how you go.