The article was about the extraordinarily hot temperatures in the Coral Sea in March this year. Here's the chart that was shown in the article, which I've copied directly from the Bureau of Meteorology:
|Figure 1 | March temperature for the Coral Sea. Source: Bureau of Meteorology.|
The authors of the article. an impressive team led by Andrew King, referred to the recent major bleaching event and wrote:
To find out how climate change is changing the likelihood of coral bleaching, we can look at how warming has affected the likelihood of extremely hot March sea temperature records. To do so, we use climate model simulations with and without human influences included.What they found was that the observed March temperature in the Coral Sea was 175 times more likely with climate change than if there had not been human-caused global warming and only internal variability. The method used is one I've written about before in another context, analysing Fraction Attributable Risk (FAR).
Denier deception from Bob Fernley-Jones
Well, Bob Fernley-Jones didn't like this, so he chose to misrepresent the article. It could be that he didn't understand what he was reading, of course. Who knows what's deliberate deception and what's dumb ignorance when it comes to the denialati at WUWT. Whatever it was, this is what Bob wrote about the article at The Conversation:
Importantly, the study was focussed on revelation of mass bleachings as found by aerial surveys in late March 2016 and was associated with reports of the hottest ever March in the Coral Sea, a tiny part of which is the GBR. Then, in late April with remarkable alacrity and before the 2,300 Km (1,400 miles) x ~3,000 reefs could be surveyed by divers, the five co-authors publically released their study without peer review into the public domain. The aerial surveys could not determine when the bleaching occurred (or how severe) but the author’s study assumed it was in March 2016.Bob is suggesting a few things here, which is suggestive of him wanting to mislead the ignorant at WUWT. Apart from the general tone, here are two specific things:
- He implies that there is something wrong with scientists writing about some work before any peer-reviewed publication. This is silly. Scientists are as free to write about science as much as anyone. I see nowhere that Bob had his own WUWT article peer-reviewed. (He probably uses the excuse that he's a pseudo-scientist writing disinformation for a climate conspiracy blog, so he can't be expected to subject it to review by scientists.)
- Bob is wrong when he wrote the authors assumed that the bleaching took place in March. They didn't. They said that it took place in the last few months. The opening sentence in the article Bob is writing about was: "The worst bleaching event on record has affected corals across the Great Barrier Reef in the last few months."
If Bob had looked at the website of the Australian Institute of Marine Science, referred to in the Conversation article he is disputing, he would have found this:
2016(Last updated: June 2016)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. (View the GBRMPA map for more information.)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.Coral reefs in northwestern Australia, including those near the Kimberley, Christmas Island, Scott and Seringapatam Reefs were bleached by record breaking ocean temperatures in early 2016 also. Bleaching was severe at Scott Reef and Seringapatam Reefs, and mortality was observed during bleaching surveys in April. The full extent of coral mortality on northwestern Australian reefs will be clearer following monitoring surveys towards the end of the year.
Bob Fernley-Jones' straw man
Now it's hard to tell from reading the WUWT article what point Bob is trying to make. It looks to me as if he is trying to prove coral bleaching events are not necessarily tied to hot temperatures in the Coral Sea in the month of March. Thing is - who said that hot temperatures in the Coral Sea in the month of March are the only cause of coral bleaching events? Certainly not the scientists who wrote the article at the Conversation. Nor the Great Barrier Reef Marine Park Authority. Nor anyone else I've come across. Bob wrote about the article at The Conversation:
It focussed on the month of March in 2016, when record high Sea Surface Temperatures (SST) in the Coral Sea prevailed and which coincided with an extraordinarily powerful El Niño unlike anything seen since 1998.That's correct. So far so good. But then Bob added:
Because accessible GBR data were not available until recently, it employed Coral Sea data to predict future GBR bleaching events.That's wrong. The article did not predict future Great Barrier Reef bleaching events using Coral Sea data. At least no predictions of specific events were made. The closest to any "prediction" was where the authors stated the bleeding obvious:
As the seas warm because of our effect on the climate, bleaching events in the Great Barrier Reef and other areas within the Coral Sea are likely to become more frequent and more devastating.
It's not just hot Marches...
This is where I deduced the straw man point of Bob's article. He compared March temperature anomalies in the Coral Sea with past bleaching events. He even drew a chart of March temperatures and marked bleaching events (or the ones he said he knew about).
Why would he do that?
I think he was trying to claim that because not every single bleaching events coincided with high March anomalies, hot seas in March can't cause bleaching. Apart from that being a straw man fallacy, because no scientist has ever claimed that hot Marches are the sole cause of Great Barrier Reef bleaching, that is a logical fallacy of the "it does not follow" variety. There are causes of coral bleaching other than high sea surface temperatures. For example, the Australian Institute of Marine Science has the following about recent bleaching events, being caused by excessive floods:
In the summers of 2008-2009 and 2010-2011, extreme summer seasons were associated with extremely high rainfall in Queensland. This led to flooding and the discharge of large amounts of freshwater to nearshore reefs resulting in freshwater bleaching.
The Reef is likely to experience more frequent and more serious thermal and freshwater stresses in the future, given current rates of global warming due to increasing levels of atmospheric greenhouse gases.
Other reef systems have also suffered bleaching events. For example, mass bleaching affected reefs across 12o of latitude along the Western Australian coast in 2010–2011. This was the first recorded coral bleaching for several sites, including Ningaloo reef.
Bob got quite a few things wrong in his article.
- He referred to the Conversation article as "Karoly et al". If he'd stuck to convention he would have called it "King et al", because the first listed author was Andrew King.
- Bob argued that David Karoly isn't an expert on corals and claimed he was writing outside his area of expertise. That's wrong. David Karoly and Andrew King have expertise in analysis of temperature, particularly in looking at the extent to which a particular temperature is likely to occur with only internal variability. And that was what the article at The Conversation was about.
- Bob thought that the 1997-98 bleaching event was the first recognised mass bleaching of the Great Barrier Reef. It wasn't. There was widespread bleaching in the summer of 1981-82 and again in 1983 as documented in this 1990 paper by Ernest H. Williams Jr and Lucy Bunkley-Williams.
- He implied that high temperature always causes bleaching. It doesn't. It depends how many days are above the threshold at any location.
There's more, which had to have been deliberate deception. Bob misquoted the headline. The headline of the Conversation article was:
"Great Barrier Reef bleaching would be almost impossible without climate change"
Compare that to what Bob wrote:
...and its headline claim of: “Coral bleaching … was made 175 times more likely thanks to climate change”.The difference may be subtle but is important and goes to Bob Fernely-Jones' motive. In the article, the authors worked out that the temperature of the Coral Sea for March was 175 times more likely. They didn't extend that to any estimate of the likelihood of coral bleaching. That was all Bob Fernley-Jones. Not content to dispute the science, he has to misrepresent the article he is writing about.
Bob didn't discuss the methodology for estimating the likelihood of the March 2016 high temperatures of the Coral Sea. There's no sign that he even looked at it much less understood it. Instead he misrepresented the article.
Bob claimed that the article asserted there was no link between Coral Sea temperatures in 1997/98 and 2015/16 and ENSO events. It didn't. What the authors did say was that overall, the influence of El Nino on the Coral Sea as a whole is weak and that there have been bleaching events in years other than El Nino years. That's not the same thing (as well as being a deceiver, Bob is not good at critical thinking):
The decaying El Niño event may also have affected the likelihood of bleaching events. However, we found no substantial influence for the Coral Sea region as a whole. Sea surface temperatures in the Coral Sea can be warmer than normal for different reasons, including changes in ocean currents (often related to La Niña events) and increased sunshine duration (generally associated with El Niño conditions).
Overall, this means that the influence of El Niño on the Coral Sea as a whole is weak. There have been severe bleaching events in past El Niño, neutral and La Niña years.
How hot was it?
Below is a chart of surface temperature of the Coral Sea comparing this past twelve months with the 1961 to 1990 average. Hover over the chart to see the actual monthly temperature. The hottest months on average are January, February and March. March 2016 was the hottest month (red line) although on average it is February, by a smidgen (blue columns).
And just to round things off, here is the difference from the average for each month of the past twelve. Once again, the biggest difference was in March this year. It's taking a long time to cool down and hasn't yet come near to the long term average.
So while Bob whined:
"The 20-year averages for January and February are typically hotter than the wrongly chosen month of March."This year they weren't. March was hotter than both January and February in 2016 (see Figure 2 above).
It's not just March - duh!
Given his parenthesis and exclamation point in the quote below, Bob seemed surprised to find out that it's not just March temperature highs that can cause bleaching. High temperatures in January and February can do it as well. Bob wrote:
The data support a major bleaching in February 1998 and 2002 with 1998 being the warmest although AIMS reports that 2002 was more severe. (Whilst Coral Sea temperatures were below the 20-year average in March!)There are a few things to pick on in that statement. For one thing, Coral Sea temperatures in March 2002 and in March 1998 were 0.3 above the average of the previous 20 years, not below.
There's more. Despite Bob's astonishment, in the summer of 2001/02, the average January 2002 Coral Sea temperature was the highest of any January in the record to that month. It was higher than any previous month except for February 1996, February 1998 and March 2001. The February Coral Sea temperature was also higher than any previous month except for February 1996 and February 1998. By contrast, the temperature in January 1998 was below 29 C (28.86 C), while in February 1998 it averaged 0.1 C higher than February 2002.
There are more oddities in Bob's article.
Bob didn't understand the Conversation article. Bob incorrectly implies in several places that the Conversation article was about a model to predict bleaching. It's not. The scientists modeled sea surface temperature of the Coral Sea, but they didn't claim to model or predict bleaching events. (There is a causal relationship. It's well known that high temperatures can cause coral bleaching.)
Bob incorrectly claims that there wasn't a bleaching event in 2004, when he found that the February sea surface temperature of the Coral Sea was the highest monthly average recorded to that time. There was a bleaching event. His claim that there wasn't rests on the fact that it wasn't mentioned in the article he read on the AIMS website. (That may be because it wasn't regarded as a "mass bleaching" event.) If Bob had done a bit of research and hadn't been so focused on his "all the scientists are wrong" meme, he might have learnt that there was a bleaching event early in 2004.
In one spot, Bob wrote something about March being "clearly the coolest". In fact the thirty year average (1961-1990) Coral Sea surface temperature in March (28.4 C) is as hot as January, only 0.1 C cooler than the average for February (28.5 C), and 0.4 C hotter than the December average. I would have thought that was just a slip of Bob's fat fingers except that he repeated his assertion elsewhere in his article. There he talks about a twenty year average, so I checked the last twenty years to see how different they are to the 1961-1990 averages in this regard. Well, what do you think? The March average is slightly higher than January and just 0.12 C below that of February.
I've downloaded all the monthly data from BoM and converted the anomalies to actual averages. You can see it for yourself here.
Checking bleaching risk days at different locations
Bob did get one thing sort of right, if you can ignore the tone and the false assertion wrongly implying the Conversation article analysis was wrong. He wrote:
A superior model would use daily SST’s (not monthly) on the GBR that analyses the entire hot season in at least three zones; North, Centre and South. However, the poorly understood ENSO and hot water poolings remain as an obstacle to reliable predictions.Now it's going to be a long time before there is a tool to accurately predict daily sea surface temperatures at individual locations. However there are two things that can help Bob.
The first is the Coral Reef Watch website of NOAA, which does forecast mass bleaching events.
And the second is a nifty set of charts on the AMS website, where you can select the year and see how many days are above the threshold for bleaching at different parts of the reef. There are more than Bob's suggested number of locations. They offer eight more sites than the three suggested by Bob, making eleven sites in all.
Here's a sample, using the years 2000/01 (when Bob thinks there should have been bleaching) as well as 2015/16 when there was a mass bleaching event. None of the locations show water temperature on any day rose above the bleaching indicator threshold for 2000/01. By contrast, six locations show temperatures above the threshold for 2015/16. The chart below is probably the most extreme from this year. At every temperature there were more days above the threshold this past year.
The website has an explanation of the chart above. As the black line shows, the cooler the temperature (at the left of the chart), the more days can be at that temperature without risking bleaching. Here's what the chart shows:
It shows the number of days exposure to temperatures at or above those indicated on the x-axis and how they compare to bleaching thresholds. Bleaching thresholds are site-specific and are an interpolation of sea surface temperature (SST) and exposure times between warmest non-bleaching summers and coolest bleaching summers. When the time-temperature curve exceeds the predicted bleaching threshold, sensitive corals are in danger of bleaching.
Retract, retract - cries Bob!
Like many deniers before him, Bob wants the article "retracted" from The Conversation because he doesn't like it. Sheesh. Not only is there nothing wrong with the article, but imagine if every "wrong" article was "retracted" from WUWT. You'd be left with a blog empty of all except Anthony's copies and pastes of press releases of scientific papers! (That would clean up the denierweb, wouldn't it.)
From the WUWT comments
There aren't a lot of comments. The first few include comments from people who say they don't believe scientists. In other words, just what you'd expect from a climate hoax conspiracy blog.
References and further reading
Great Barrier Reef bleaching would be almost impossible without climate change - article by Andrew King et al at The Conversation, April 2016
Barrier reef attribution study: Data and methodology - explanation of workings underpinning the above article, from the ARC Centre of Excellence for Climate System Science.
Coral bleaching events - article describing mass coral bleaching events on the Great Barrier Reef, on the website of the Australian Institute of Marine Science.
Coral Bleaching Risk Indicators and Summer Sea Water Temperatures for the Great Barrier Reef - interactive graphs from the Australian Institute of Marine Science, showing the risk of bleaching in different years from 1998/99 onward.
Record-breaking hot years almost impossible without humans - and Anthony Watts' conspiracy theory - HotWhopper article from March 2016, with a description of Fractional Attributable Risk (FAR).