Falling Sea Level: The Critical Factor in 2016 Great Barrier Reef Bleaching!

Guest essay by Jim Steele

Director emeritus Sierra Nevada Field Campus, San Francisco State University and author of Landscapes & Cycles: An Environmentalist’s Journey to Climate Skepticism


It is puzzling why the recent 2017 publication in Nature, Global Warming And Recurrent Mass Bleaching Of Corals by Hughes et al. ignored the most critical factor affecting the 2016 severe bleaching along the northern Great Barrier Reef – the regional fall in sea level amplified by El Niño. Instead Hughes 2017 suggested the extensive bleaching was due to increased water temperatures induced by CO2 warming.

In contrast in Coral Mortality Induced by the 2015–2016 El-Niño in Indonesia: The Effect Of Rapid Sea Level Fall by Ampou 2017, Indonesian biologists had reported that a drop in sea level had bleached the upper 15 cm of the reefs before temperatures had reached NOAA’ Coral Reef Watch’s bleaching thresholds. As discussed by Ampou 2017, the drop in sea level had likely been experienced throughout much of the Coral Triangle including the northern Great Barrier Reef (GBR), and then accelerated during the El Niño. They speculated sea level fall also contributed to the bleaching during the 1998 El Niño. Consistent with the effects of sea level fall, other researchers reported bleaching in the GBR was greatest near the surface then declined rapidly with depth. Indeed if falling sea level was the main diver in 2016’s reef mortalities, and this can be tested, then most catastrophic assertions made by Hughes 2017 would be invalid.

Indeed the Great Barrier Reef had also experienced falling sea levels similar to those experienced by Indonesian reefs. Visitors to Lizard Island had reported more extreme low tides and more exposed reefs as revealed in the photograph above, which is consistent with the extremely high mortality in the Lizard Island region during the 2016 El Niño. Of course reefs are often exposed to the air at low tide, but manage to survive if the exposure is short or during the night. However as seen in tide gauge data from Cairns just south of Lizard Island, since 2010 the average low tide had dropped by ~10 to 15 cm. After previous decades of increasing sea level had permitted vertical coral growth and colonization of newly submerged coastline, that new growth was now being left high and dry during low tide. As a result shallow coral were increasingly vulnerable to deadly desiccation during more extreme sea level drops when warm waters slosh toward the Americas during an El Niño.


Furthermore, an El Niño in the Coral Triangle not only causes a sudden sea level fall, but it also generates a drier high-pressure system with clear skies, so that this region is exposed to more intense solar irradiance. In addition, El Niño conditions reduce regional winds that drive reef-flushing currents and produce greater wave washing that could minimize desiccation during extreme low tides. And as one would predict, these conditions were exactly what were observed during El Niño 2016 around Lizard Island and throughout the northern GBR.

Aerial surveys, on which Hughes 2017 based their analyses, cannot discriminate between the various causes of bleaching. To determine the cause of coral mortality, careful examination of bleached coral by divers is required to distinguish whether bleached coral were the result of storms, crown-of-thorns attacks, disease, aerial exposure during low tides, or anomalously warmer ocean waters. Crown-of-thorns leave diagnostic gnawing marks, while storms produce anomalous rubble. Furthermore aerial surveys only measure the aerial extent of bleaching, but cannot determine the depth to which most bleaching was restricted due to sea level fall. To distinguish bleaching and mortality caused by low tide exposure, divers must measure the extent of tissue mortality and compare it with changes in sea level. For example, the Indonesian researchers found the extent of dead coral tissue was mostly relegated to the upper 15 cm of coral, which correlated with the degree of increased aerial exposure by recent low tides. Unfortunately Hughes et al never carried out, or never reported, such critical measurements.

However a before-and-after photograph presented in Hughes 2017 suggested the severe GBR bleaching they attributed to global warming primarily happened between February and late April. Their aerial surveys occurred between March 22 and April 17, 2016. And consistent with low tide bleaching, that is exactly the time frame that tide tables reveal reefs experienced two bouts of extreme low tides coinciding with the heat of the afternoon (March 7-11 & April 5-10). And such a combination of sun and low tide are known to be deadly.

A study of a September 2005 bleaching event on Pelorous and Orpheus Islands in the central GBR by Anthony 2007, Coral Mortality Following Extreme Low Tides And High Solar Radiation, had reported extreme deadly effects when extreme low tides coincided with high solar irradiance periods around midday. As in Indonesia, they also reported bleaching and mortality had occurred despite water temperatures that were “significantly lower than the threshold temperature for coral bleaching in this region (Berkelmans 2002), and therefore unlikely to represent a significant stress factor.” Along the reef crests and flats, “40 and 75% of colonies in the major coral taxa were either bleached or suffered partial mortality. In contrast, corals at wave exposed sites were largely unaffected (<1% of the corals were bleached), as periodic washing of any exposed coral by waves prevented desiccation. Surveys along a 1–9 m depth gradient indicated that high coral mortality was confined to the tidal zone.” [Emphasis mine]

The fortuitous timing of Ampou’s coral habitat mapping from 2014 to 2016 in Bunaken National Park (located at the northwest tip of Sulawesi, Indonesia) allowed researchers to estimate the time of coral mortality relative to sea level and temperature changes. Ampou reported that in “September 2015, altimetry data show that sea level was at its lowest in the past 12 years, affecting corals living in the bathymetric range exposed to unusual emersion. By March 2016, Bunaken Island (North Sulawesi) displayed up to 85% mortality on reef flats” and that almost “all reef flats showed evidence of mortality, representing 30% of Bunaken reefs.” Based on the timing of reef deaths and changes in temperature they concluded, “the wide mortality we observed can not be simply explained by ocean warming due to El Niño.” They concluded, “The clear link between mortality and sea level fall, also calls for a refinement of the hierarchy of El Niño impacts and their consequences on coral reefs.”

From the illustrations (below) of a generalized topography of a fringing or barrier reef, we can predict the effects of low sea level by examining where bleaching and mortality would occur within the whole reef system. Coral occupying the reef crests are most sensitive to drops in sea level and desiccation because they are first to be exposed to dangerous periods of aerial exposure and last to re-submerge. The inner reef flats are vulnerable to lower sea levels, as those shallow waters are more readily exposed at low tide because the reef crest prevents ocean waters from flooding the flats. If reefs flats are not exposed, the shallow waters that remain can heat up dangerously fast. Accordingly Anthony 2007 found 40 to 75%, and Ampou 2017 found 85% of the reef flats had bleached. In contrast coral in the fore reefs are the least vulnerable to desiccation and higher temperatures due to direct contact with the ocean, upwelling and wave washing. Accordingly Anthony 2007 reported <1% bleaching in the fore reefs.


Coral mortality due to a drop in sea level leaves other diagnostic telltale signs such as micro-atoll formation. As illustrated below in Fig. 4 from Goodwin 2008, during neap low tides (MLWN) sea water can still pass over the reef crest and flush the inner reef with relatively cooler outer ocean water. However during the low spring tides (MLWS), the reef crest is exposed and ocean water is prevented from reaching the reef flats. As mean sea level falls (MSL), coral on the crest and flats are increasingly exposed to the air for longer periods, and the upper layer of coral that had previously kept up with decades of rising sea level, are now exposed to increasing periods of desiccation and higher mortality.


There are over 43 species in the coral triangle that can be characterized as “keep-up” coral whose growth rates are much greater than average 20th century sea level rise. However their vertical growth is limited by the average low water level (HLC-Height of Living Coral in Fig. 4). Average low water level is calculated as the mean water level between low neap tides and lower low spring tides. (Due to the linear alignment of the sun, earth and moon and the resulting stronger gravitational pull during a full and new moon, spring tides result in both the highest high tides and lowest low tides. In contrast neap tides exert the least gravitation pull. Spring tides typically happen twice a month, but usually no more than once a month will spring low tides coincide with the heat of the midday sun.)

When growing in deeper waters, a keep-up species like mounding Porites spp. grow at rates of 5 to 25 mm per year and form dome shaped colonies. However due to increased aerial exposure when growth reaches the surface, or due to exposure from sea level fall, the upper most surface dies from high air temperatures, higher UV damage and desiccation. This results in a flat-topped colony leading to the classic “micro-atoll” shape, with dead coral in the center surrounded by a ring of live coral, as exemplified by a Kiribati micro-atoll in the photograph below.


Micro-atoll patterns have been crucial for reconstructing past fluctuations in sea level on decadal to millennial timeframes. As Ampou 2017 observed in Bunaken NP, mortality due to a drop in sea level was mostly restricted to the upper 15 cm of coral, which leads to the formation of micro-atolls. So before simply assuming climate-change-warming has induced mortality, micro-atoll formation and other associated patterns indicative of sea level change must be examined. A short discussion on how sea level changes can shape micro-atolls can be read here.

Due to its regional sensitivity to the sea level change that accompanies an El Niño, the northern Great Barrier Reef has an abundance of fossil micro-atolls that have allowed researchers to estimate El Niño activity and fluctuating sea levels over the past 4000 years. They estimated 4000 years ago low water neap tides were at least 0.7 meters higher than they are at present. Studies of micro-atolls in the Cook Islands further to the east in the southern Pacific, suggest that by 1000 AD during the Medieval Warm Period, average sea level had fallen, but remained about 0.45 meters higher than today. During the Little Ice Age sea level fell to 0.2 meters below current levels during the late 1700s and early 1800s, before recovering throughout the 1900s.

Hughes 2017 wanted to emphasize GBR bleaching as a “global-scale event” in keeping with his greenhouse gas/global warming attribution, but bleaching and mortality was patchy on both local and regional scales. And although Hughes presented their analyses as “a fundamental shift away from viewing bleaching events as individual disturbances to reefs,” the unusually high mortality around Lizard Island demands a closer examination of individual reef disturbances. The lack of mortality in 2016 across the southern and Central GBR, was explained as a result of the cooling effects of tropical storm Winston, but that does not explain why individual reefs in those regions have not bleached at all, while others bleached only once, and still others bleached twice or three times since 1998. Hughes’ shift away from examining what factors affected individual reefs will most likely obscure the most critical factors and yield false attributions.


Hughes reported the various proportions of areal bleaching as degrees of severity. But that frightened many in the public who confused bleaching with mortality, leading some misguided souls to blog the GBR was dead. However bleaching without mortality is not a worrisome event no matter how extensive. Rates of mortality and recovery are more important indices of reef health. As discussed in the article The Coral Bleaching Debate: Is Bleaching the Legacy of a Marvelous Adaptation Mechanism or A Prelude to Extirpation?, all coral retain greater densities of symbiotic algae (symbionts) in the winter but reduce that density in the summer, which often leads to minor seasonal bleaching episodes that are usually temporary. Under those circumstances coral typically return to normal within weeks or months. Furthermore by ejecting their current symbionts, coral can acquire new symbionts that can promote greater resilience to changing environmental conditions. Although symbiont shifting and shuffling promotes adaptation to shifting ocean temperatures, symbiont shuffling cannot protect against extreme low tide desiccation, and dead desiccated coral can no longer adapt. Humans have little control over El Niños or low tides.

Hughes also contradicted past studies to mistakenly suggesting that recurring bleaching in a given reef is evidence that corals are not adapting or acclimating. However bleaching happens for many reasons. Symbiont shuffling to better adapt to warmer waters does not guarantee adaptation to lower sea levels, cyclones or changes in salinity. Coral reefs deal with changing sea levels with rapid growth to keep-up as sea level rises, and then dying back when sea level falls. Decadal swings in regional sea level will likely cause decadal swings in bleaching and are not evidence of coral fragility.

Hughes 2017 modeled the 2016 GBR bleaching event as a function of surface ocean temperatures that surpass bleaching thresholds, although reefs will bleach below that threshold and will fail to bleach despite temperatures above that threshold. Despite the fact El Niños are well known to cause rapid sea level fall along the GBR, Hughes’ model never accounted for falling sea level. Nor did they account for past observations that falling sea levels induced bleaching when temperatures were below bleaching thresholds. More disturbing because sea level fall caused bleaching in various reefs, with some experiencing good water quality and others poor quality, Hughes asserted there was “no support for the hypothesis that good water quality confers resistance to bleaching.” However this contradicts an abundance of regional studies attributing increased coral disease and bleaching to high nutrient loading.

Woolridge 2013 have argued that coral eject their algal symbionts and bleach when temperature, light and nutrients increase to a level that accelerates the symbionts growth. Increased growth consequently reduces the amount of energy transferred to the coral, resulting in ejection of the slacking symbiont. Because increased nutrient loads can promote increased symbiont growth at relatively lower temperatures, higher nutrient loads can promote bleaching at lower temperatures.

Furthermore while coral’s symbiotic relationships allow them to recycle limited nutrients and out compete seaweeds, higher nutrient loads enable greater seaweed growth, which reduces corals’ competitive advantage. Furthermore seaweeds have been shown to harbor allelopathic chemicals that inhibit coral growth, as well as serving as reservoirs for bacteria that cause coral diseases. Higher nutrient loads induce more dissolved organic carbon that bacteria feed upon, allowing disease-causing bacteria to rapidly multiply. Higher nutrient loads also increase the survival of crown-of-thorns larvae, which then increases coral depredation and bleaching.

In a 2013 experimental study, Chronic Nutrient Enrichment Increases Prevalence And Severity Of Coral Disease And Bleaching, Vega-Thurber reported that higher nutrient loads caused a “twofold increase in both the prevalence and severity of disease compared with corals in unenriched control plots” as well as a “3.5-fold increase in bleaching frequency relative to control corals.”

Although Hughes 2017 suggests the pattern of recurring bleaching is simply a function of temperature and global warming, as illustrated in Hughes’ Figure “e” below, recurring bleaching is not a global phenomenon. (Black dots represent reefs that bleached during all 3 surveys: 1998, 2002, 2016; light gray represents reefs that bleached only once, and dark gray reefs bleached twice.) . In most cases the degree of recurring bleaching does not predict the recurrence of bleaching in nearby reefs despite similar ocean temperatures. Although an El Niño generates widespread bleaching, bleaching is still a regional issue affecting individual reefs differently. During an El Niño sea level rises in the eastern Pacific and falls in the western Pacific. Recurring bleaching in the Far North and Southern regions of the GBR are uncommon, while recurring GBR bleaching has been frequent between Cookstown and Townsville where temperatures have been quite variable. And in accord with prior research, the region between Cookstown and Townsville has suffered from lower water quality and higher nutrients loads, causing more frequent bleaching and greater crown-of-thorns attacks.


After perusing Hughes 2017, it was clear they had been led to incorrectly embrace the prevailing bias of CO2-induced catastrophic bleaching because they failed to address the fall in sea level before and during the 2016 El Niño, and likewise they failed to address how weather created by El Niños promotes clear skies and increased solar heating. To add insult to injury, because sea level drops bleached reefs in both good water quality and bad, and bleaches reefs in both protected preserves and unprotected, Hughes 2017 presented a statistical argument that disparaged any significant value of ongoing conservation efforts to minimize bleaching by reducing nutrient loading and by protecting reefs from overfishing. By belittling or ignoring most critical factors affecting coral bleaching other than temperature, Hughes suggested our only recourse to protect reefs “ultimately requires urgent and rapid action to reduce global warming.”

And because such an apocryphal analysis was published in Nature and will undoubtedly mislead coral conservation policies,

I wept.



Jim Steele is author of Landscapes & Cycles: An Environmentalist’s Journey to Climate Skepticism

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April 5, 2017 5:17 am

and are you submitting this post to the Journal in question as part of a sound rebuttal?

Reply to  AleaJactaEst
April 5, 2017 7:14 am

Second the motion. Much better than weeping.

Reply to  Gary
April 5, 2017 9:26 am

Amen! Jim Steele, this is superb work.

Jim Steele
Reply to  Gary
April 5, 2017 10:32 am

Gary, I was parodying Hughes’ tweet that WAPO’s Mooney and others hyped back in April 2016 claiming 93% of the GBR had bleached.

Hughes tweeted, “I showed the results of aerial surveys of #bleaching on the #GreatBarrierReef to my students, And then we wept.”

Reply to  Gary
April 5, 2017 4:03 pm

Not enough stars for an exceptionally clear rebuttal. Thank you.!

Reply to  Gary
April 6, 2017 1:38 am

JS … they probably did the aerial survey at low tide with the sps exposed.

Reply to  AleaJactaEst
April 5, 2017 8:58 am

the idea of publishing something at all cost, publish or perish, had resulted in a hyperinflation o papers with dubious scientific merit. This is the present problem in science today.

Jim Steele
Reply to  AleaJactaEst
April 5, 2017 9:26 am

A much wider audience is often reached by publishing in WUWT than in a journal. I have had several experts email me in response to WUWT posts. We could have a much greater impact if this post gets re-blogged in as many places as possible and we create a public stir forcing a more critical examination of the gloom and doom scientists.

Reply to  Jim Steele
April 5, 2017 12:23 pm

you do quality work.
any excuse to cerebrate!

Reply to  Jim Steele
April 6, 2017 5:20 am

Doom and gloom? I suspect GBR is well and in good shape then! Best wishes to you!

Reply to  AleaJactaEst
April 9, 2017 7:57 pm

Jim does not post these pieces of fiction in science journals. He could never survive peer-review when his only real aim is to try and pretend that that climate change and global warming are not happening. Tough to get approval for propaganda that ignores the obvious reality of hot water caused by climate change and global warming causing coral bleaching and death.

Reply to  Tripp Funderburk
April 10, 2017 4:05 am

Are you writing this as a serious comment or are you attempting to claim ownership of a new form of wit?

Reply to  Tripp Funderburk
April 13, 2017 8:13 pm

It would be nice Tripp if you could actually refute anything in the article rather than just attack Jim Steele. That is the reason you doom and gloomers are not winning and are treated as a bit of a joke.

April 5, 2017 5:20 am

It would appear Hughes et al. got a grant for a drone, then wondered what could be done with it.

“I know” say’s Hughes, “lets use it to spy on coral reefs, we can ignore everything else of importance relative to coral bleaching and rely on the drone, it’s bound to be right because they are all the rage and I’m sure they’re useful…….besides, they’re fun”

April 5, 2017 5:21 am

“And because such an apocryphal analysis was published in Nature and will undoubtedly mislead coral conservation policies”

So much for peer review in the journal Nature.

April 5, 2017 5:29 am

The funny thing about the ENSO is that sea level in the Western Pacific moves in the opposite direction of the global average.

Reply to  David Middleton
April 5, 2017 9:25 am

Aren’t the higher sea temperatures also in the eastern pacific when ENSO is active.

Alan Chappell
Reply to  rocketscientist
April 6, 2017 2:35 am

In 1996 I sailed from Auckland New Zealand to Norfolk Island, about 250 miles from Norfolk Island the engine Temp. alarm sounded, after checking it was found that the seawater Temp. was 62c as it was 04.30 in the morning we decided to wait for daylight before continuing and sail away ( no engines ) the water depth was about 3,500 meters , in daylight the seawater was gas adutated, the air had a metallic flavor, continuing on some miles you could see a bump on the horizon, I saw no dead fish ( to smart ) but as this was in the region ? ( Norfolk Island is Australian )

Rich Van Slooten
April 5, 2017 5:31 am

I appreciate this analysis. Its very important to consider all the variables involved in coral bleaching rather than just focusing on one particular variable. As a scuba diver I have always been fascinated by coral types, structure, growth and overall health. I have come to realize that coral bleaching scenarios are not always easy to attribute without extensive historical analysis of the the particular reef in question.

Jeff in Calgary
Reply to  Rich Van Slooten
April 5, 2017 9:38 am

The CAGW Alarmists have put on blinders and can only see one potential cause for all things negative (while seeing many (all but one?) possible causes for anything positive). Isn’t there a name for that? Kind of like Conformation Bias?

Reply to  Rich Van Slooten
April 5, 2017 3:27 pm

When is someone going to mention that bleaching does not mean the coral is dead, only that the coral polyps, the actual cnidarian host and builder of the reef, have ejected the algae symbionts from the colony.
After some interval, they take on new symbiotic algae, often of a different strain or species which is better suited to the then prevailing conditions.
The impression is widely given this is a dying, and is unnatural, and permanent.
It is none of those.
It is how they survive stressful conditions.
If the stress is long lasted, some coral polyps do eventually die.
But even these dead skeletons can be, and often are, recolonized.

M Seward
April 5, 2017 5:34 am

Makes a lot more sense than the CAGWarmista propaganda but I can just hear the squeals from Queensland “but Steele is not an expert!!”

The author really should get this bublished in a related journal tthough

john harmsworth
Reply to  M Seward
April 5, 2017 12:22 pm

Well apparently Hughes is not an expert either. Nor are his peer reviewers on this paper. It’s incomplete to the point of being incorrect. More climate garbage from Nature and they have no excuse, having been fooled repeatedly by the AGW crowd. Why do they choose not to closely scrutinize these papers? Smells like collusion to me.

Reply to  john harmsworth
April 9, 2017 8:01 pm

28 of the best marine biologists and scientists from Australia’s best universities and research laboratories are not experts?

Ian W
Reply to  john harmsworth
April 13, 2017 4:04 pm

Tripp – obviously not if they believe an aerial survey (with a nice shiny drone) is a substitute for divers assessing damage. They are probably world experts in getting research funding though. So who cares about the real reason for bleaching.

Reply to  M Seward
April 10, 2017 4:16 am

Dear dear Tripp, still stuck with the idea that group think = truth? There are fundamentals which “used” to be a prerequisite for credible work in any scientific field. Never start with a conclusion, be open minded, always skeptical and consider ALL possible data. In your summing up the most critical data to reveal is that which does not agree with your hypothesis and you should why you think it does not. Ignoring contradictory data is at best disingenuous and at worse fraud!

Jim Steele
Reply to  M Seward
April 10, 2017 12:56 pm

Trip is just doing his usual sniping and shoot the messenger tactic that signifies he has nothing scientific to add

April 5, 2017 5:35 am

It is usually best to look at endpoints and what happens between them to get a good feel for what is going on. Sea level has risen 120 meters since the end of the last ice age. (About 20K years) It has risen about 25 meters just in the last 7500 years. It has pretty much leveled off, but is still rising slightly with slight regression happening occasionally.
A true perspective can be seen in this link:
Chart of last 20K years:
The point here is that corals managed to survive and prosper throughout this process. A 500 foot sea rise and the coral just adapts. So, just looking at the last few years, and in particular the El Nino years, is like trying to understand an alligator by looking at the last scale of its tail.
It is always disappointing to me when really contextual information is missing in reports that simply try to make a point, but critical contextual facts are left out, as those facts would quickly show how skimpy the research was.
After reviewing the chart linked above, as yourself whether this report contributes to understanding of corals at all. Better yet, how much better it would have been to write about how adaptable coral actually is.

Reply to  John
April 5, 2017 6:14 pm

Can somebody please tell me if a similar shore line- sea level anaysis has been done for the Australian/New Zealand/Indonesia-PNG region?

Warren Blair
Reply to  DaveR
April 6, 2017 4:03 am

Record Antarctic melting 2016/2017; you’ve seen the headlines.
November 2016 to February 2017 Australian sea-level movements are in the negative despite record melting at Australia’s back door.
Australian Bureau of Metrology established the Australian Baseline Sea Level Monitoring Project in the early 90s to monitor dangerous sea-level rise due to climate change (a UN initiative).
Tens of millions spent on satellite-calibrated ground stations equipped with the World’s best monitoring technology.
Unfortunately for the UN there’s no AGW signature in the data so it’s never mentioned by them.
Worse, the US EPA boldly quote the Australian CSIRO who simply use models and fiddling to promote the notion of dangerous sea-level rise.
The Australian Bureau of Metrology (BOM) is the expert in Australia (not the CSIRO); however, the US EPA ignores the BOM as a source of data when indeed it’s the definitive source in our region.
The CSIRO and NOAA are known for fiddling data at the request of leftist politicians.

April 5, 2017 5:37 am

Also from down under Jo Nova’s latest. http://joannenova.com.au/2017/04/i-thought-the-laws-of-physics-worked-for-both-sexes/#comments

Reading this may also make you weep – We truly live in a stupid time

John Furst
April 5, 2017 5:37 am

Thank you. Another full analysis of a much more complex causality than “Nature” article represents. A continued professional and informational author. With high quality analyses by Steele, and others, there is still hope that other scientists and publications will finally align the policies with more complete science.

April 5, 2017 5:39 am

Just sent the link to this article to the Aussie ABC with a challenge to go ahead and report on it as if it was a press release from the gravy-train passengers at James Cook Uni. Let’s see if they can publish just one article from a sceptical perspective. They won’t, of course, but it supports the case I’m preparing for the Minister based on a series of rejected complaints to the ABC about their bias.

Also sent it to the Cairns Post newspaper – the nearest regional daily newspaper to the bleached area. They lap up JCU’s fake news; let’s see if the acknowledge this. (Again, they won’t, but a lefty journo may suffer cognitive dissonance and that’s always fun.)

Jim Steele
Reply to  Beliaik
April 5, 2017 7:23 am

Bob Fernley-Jones sent me a link to March 27, ABC attack on Graham Lloyd for not discussing coral bleaching and again attacked me for being a “bird expert”.


The ABC basically repeated their shoot the messenger tactics that they used last year


Reply to  Jim Steele
April 5, 2017 5:40 pm


Thank you very much for your outstanding research. It is very much appreciated here in the Cairns area and in North Queensland generally.

We (the NQ sceptical community) fight an endless battle trying to get the truth about the reef out to the public because one of our main industries is reef tourism.

Recently JCU’s alarmists and their comrades at the local Reef and Rainforest Research Centre asked for $9 million to pump cold water onto the reef to stop bleaching.

It annoyed me enough to start a petition to get them stopped (mentioned down-thread). I just updated the petition and directed supporters to your work. Copied below. Again, sincerest thanks!



G’day, I’d like to thank you again for signing this petition and for alerting others to its presence here on change.org.

Acclaimed researcher Jim Steele has just released an excellent essay on the causes of GBR bleaching. (Jim is Director Emeritus Sierra Nevada Field Campus, San Francisco State University and is author of Landscapes & Cycles: An Environmentalist’s Journey to Climate Skepticism.)

Jim explains how the effects of the natural El Nino cycle, with its capacity to change local sea-levels and cause corals to bleach, seem to have been ignored by James Cook University’s “ARC Centre of Excellence for Coral Reef Studies”.

How can JCU’s “scientists” be trusted when it is so simple to debunk their “peer reviewed and published” research?

Can researchers who ignore reality in order to draw unprovable links to the fuels that are vital to our advanced technological societies even be called “scientists”?

Let’s stop this nonsense now. Get your friends and family to sign and together we can save the reef from ideologically-motivated JCU employees.

Jim Steele’s essay can be found here – https://wattsupwiththat.com/2017/04/05/falling-sea-level-the-critical-factor-in-2016-great-barrier-reef-bleaching/ – and it has been re-blogged at many other sites.

April 5, 2017 5:44 am

Here is the link to Nature Magazine for authors. Somewhere in there they mention “peer review”. Hopefully they have turned a new leaf?


Reply to  rbabcock
April 5, 2017 10:33 am

Nope. The Nature publication was taken over in the last 30 years one by one by believers in global infinite warming.

April 5, 2017 5:47 am

I visited Thailand in 2015 and I noticed a lot of dead coral reefs. But the cause seemed obvious to me, these corals spent a large part of each day above the surface of the water, baking in the scorching hot midday sun.

How anyone could conclude that the corals died because of CO2 is beyond any science that I was taught.

Reply to  klem
April 5, 2017 9:37 am

Having recently returned from the Similan Islands in the Andaman Sea, my observations have determined that most of the coral destruction in this area was primarily due to mechanical destruction caused by the storms and the 2004 tsunami which devastated the reefs. I saw very little if any bleaching. The initial surge from a tsunami does some damage, however it is the back flow from all of the land debris that completes the destruction. I have scuba dived the GBR and the reefs around Papua New Guinea. The only bleaching I noticed was local and due to changes in upwelling patterns around the outer reefs.

April 5, 2017 5:48 am

Great article. But please don’t weep, or, if you do, please don’t tell us about it. Weeping, crying, and sobbing – in fact any lachrymose activity – is the faux-truth sign of the left, hence a sign that an argument has no veracity.

Jim Steele
Reply to  Mark
April 5, 2017 6:57 am

Mark, I was parodying Hughes’ tweet that WAPO’s Mooney and others hyped back in April claiming 93% of the GBR had bleached.

Hughes tweeted, “I showed the results of aerial surveys of #bleaching on the #GreatBarrierReef to my students, And then we wept.”

john harmsworth
Reply to  Jim Steele
April 5, 2017 12:39 pm

I think your findings on this matter sound reasoned and informed, Jim. It occurs to me that some honest and thoughtful marine biologist should call you up to collaborate on a paper or make an attempt to verify your findings. Whether you get some credit or not is hard to say but that might get your ideas published at least.

April 5, 2017 5:49 am

Thanks Jim,
Another keeper for me. I live near the shore of the GBR central zone. Yes, there may still be a bit more nutrient run-off, but a huge amount of work has been done by Landcare groups around the Hinchinbrook area. I doubt the Crown of Thorns issue is derived from nutrients. Apparently they are more common on the outer reef areas.
The sea level here has certainly not risen. May still be dropping a bit or it could be change in local coastal topography. The ground level at my property was always given as 3.9m AHD (MSL) but is now said to be 4m. Possibly a correction to the cadastral database, but there have been several studies that show a drop since the mid-Holocene highstand. Plate tectonics may also have an effect. “Australia has moved 1.5 metres north over the past 22 years, putting it out of sync with global positioning systems. The Australian plate is the fastest continental plate on the planet, moving northwards and slightly to the east by about 7 centimetres each year.” [ScienceAlert] If that goes on, then the flow-through from the West Pacific warm pool into the Indian ocean will be blocked.

Reply to  Martin Clark
April 5, 2017 7:00 am

The wide variation in bleaching along the GBR might suggest a falling sea level and tidal variation may not be the only driver of bleaching. The sea level variation my be complicated by an element of tectonic uplift focused on the Northern sector around Cooktown.
The 10cm increase in the elevation of your property my be real and complicate the notion of sea level change along the length of the reef.

john harmsworth
Reply to  Martin Clark
April 5, 2017 12:42 pm

” Australia has moved 1.5 meters North over the past 22 years”. Come on mate! We’re saving you a parking space off the West coast of Canada!

Reply to  john harmsworth
April 5, 2017 3:35 pm

Oh, man!
I need a new globe now!

Reply to  john harmsworth
April 6, 2017 5:08 am

New product idea: globe with movable continental plates.

Reply to  Martin Clark
April 5, 2017 3:54 pm

The Indo-Australian Plate moves at different rates. Where India is colliding with the Eurasian Plate, it’s slowed by the upthrust of the Himalayas. Australia is colliding with the less resistant microplates around New Guinea at about 5.6 cm per year:


That’s 18.4 feet per century, if my arithmetic serves.

George Tetley
Reply to  Martin Clark
April 6, 2017 2:48 am

Australia is running away ? SO MANY HAPPY KIWI’S

Reply to  George Tetley
April 8, 2017 9:52 pm

Ah, but didn’t NZ move around a bit in a recent earthquake?

Warren Latham
April 5, 2017 5:52 am

Let the bleaching begin.

April 5, 2017 5:54 am

How long does it take a coral to evolve?

Because they have all evolved to use bleaching as a survival tool……..

Reply to  Latitude
April 5, 2017 6:19 am

ditto forest fires I believe.

Reply to  climanrecon
April 5, 2017 9:15 am

Coral use forest fires to survive? I’d love to hear more about that.

April 5, 2017 5:55 am

“I wept”……

Yeah, me too, every time I hear an ABC pundit claim “global warming” (I refuse to use the weasel term “climate change”) is causing the GBR to “die”, or read some inane article claiming the same. There is a flat refusal to consider any other option, in a world filled with other options for reasons or explanations or even theories for all the mad things they claim are caused by “global warming”.

Really, is there no intelligent life out there in the media, in any bureaucracy or government? OK, OK, sorry, I do know better.

Reply to  Bushkid
April 5, 2017 9:07 am

We can’t demonstrate the 1st derivative so let’s claim it causes the 2nd .

Reply to  Bushkid
April 5, 2017 10:16 am

“And pray that there is intelligent life somewhere out in space because there is bugger all down here on earth”.

Gary Pearse
April 5, 2017 5:57 am

Jim, excellent reef education for an engineer and geologist in the mining and mineral processing sector. I can tell you a good engineer would have investigated the main physical and chemical parameters you pointed out (and researched the rest) to determine what was causing the bleaching. I’m sure a good biologist/ ecologist doesn’t permit himself to take liberties in such studies to choose his conclusions subjectively. An engineer can go to jail if he does! The GBR is put at great risk with bad science.

I recall your fine report on the Edith Spot butterfly, analyzing the bad science done to falsely promote the same lies about CO2 and CAGW. Also, on the extinction of the Golden Toad in Costa Rica used for the same political purpose, when it was because amphibian researchers visiting populations of frogs and toads around the world to find the best for production of the testers for pregnancy in women, used unclean equipment and rubber gloves contaminated with a deadly virus from a South African toad! Shameful and a threat to species by ‘researchers’.

Reply to  Gary Pearse
April 5, 2017 10:37 am

I remember that story! It was shocking. Indeed, many ‘studies’ of wild animals involves a tremendous amount of drugging them, messing around with them, touching them, injecting them or withdrawing blood, etc. Over and over and over again. Any excuse to make money doing this is framed as ‘necessary’ even when it does nothing to ‘save’ any animals.

Ian Magness
April 5, 2017 6:12 am

Great analysis, thank you so much Jim.
I can now add coral bleaching to tree ring growth and glacier growth/retrenchment (I’m sure WUWT readers can come up with many more) when discussing matters that warmistas love to ascribe only to global warming but, as ever, the subjects are much more complicated than that and CO2 levels may not even be relevant.

feed berple
April 5, 2017 6:13 am

Jim, great analysis. What about rainfall during el nino? Fresh water kills coral which is why atoms often have passes on the leeward side.

April 5, 2017 6:31 am

I used to be a commercial crayfish diver way back in the late 80’s early 90’s in the Torres Straits. I once posited the thought to a Marine Biologist that “big outs” (low tides) during the hottest part of day probably caused more coral bleaching than anything else….. and he laughed at me.

For a couple of seasons, there was a whole bunch of “marine scientists” camped on Tudu Island on Warrior reef in the Torres Straits trying to catch and tag Panulirus Ornatus, a migratory tropical rock lobster. They used to come measure the width and record the sex of our crayfish tails… mainly because they couldn’t catch any to tag.

They couldn’t catch crayfish to save their lives and they couldn’t do science to pay their lunch…. But they certainly could scam a pretty penny from government funding and the taxpayer payed through the nose for their “science”…. The commercial cray diving industry and commercial fishing in general payed for it a bit later through crazy regulations based on their “Science”.

….. But anyhoo…. This “marine biologist” thought it was a hoot that one of the taxslaves had an opinion…. certainly tickled his funnybone. Low tides bleaching coral en masse! n’yuk, n’yuk, n’yuk…LOL.

But no matter his opinion….The water that flows off the reef during these dead flat “glassed out” days, is uncomfortably hot…. like a hot bath. As it flows off the reef top, into the littoral zone, it is about three meters deep, brown on the top and hot, becoming greenish until it disperses in the cold clear blue of the ocean….. and this is during the neap tides, where shallow water remains on the reef at low tide to heat up to 40C or more… During the spring tides on these kind of days. The coral for the entire length of the GBR is exposed to the direct sun for hours…. and shallow areas heated up….. some areas must cop a flogging health wise during these times.

Anyway, that’s my two cents worth… despite his mirth, I always thought coral would suffer in these naturally extreme conditions…. and that it would also naturally bounce back without too much drama.

Coral bleaching is normal,not abnormal…. But to the marine “scientists” it is mana from heaven funding wise.

Reply to  J.H.
April 5, 2017 8:47 am

Excellent anecdotal evidence. I’m no scientist but my belief is that local knowledge is usually the foundation of good investigation (of which I have considerable experience). E.G. If you go to Mars and meet a Martian, you don’t tell him how to live, you ask him how he lives. Precisely what your scientist didn’t do, he just made it all up to suit his purposes and determined, as many do, that their version of ‘measurements’ are the only valid ones.

April 5, 2017 6:48 am

“When the truth doesn’t match the narrative, ignore the truth.”


Don K
April 5, 2017 7:03 am

Jim. Very interesting as usual. I wonder if you have any reservations about the methodologies used to determine the extent of coral bleaching.

I looked into the subject very superficially last year because it appeared to me that the places in the Pacific where El Nino coral bleaching was being reported seemed a rather dubious match to the elevated El Nino sea surface temps that were purportedly responsible

I came away feeling that:

1. The areas involved are vast, mostly remote, and largely sparsely populated
2. Underwater surveying of bleaching is possible, but not very practical at scale because the areas are huge.
3. Arial surveying is possible, but is a lot harder than it sounds. And it’s not likely to work well for anything but near surface exposures.
4. Satellite surveying may be possible, but it has the same problems as arial surveying plus requiring recent, very high resolution imaging that probably isn’t available unless someone is willing to spend what I would assume to be fairly serious money.

So, how good are the numbers?

Gary Pearse
Reply to  Don K
April 5, 2017 7:12 am

Traverses on a grid are adequate for ‘sampling’ the reef. Detailed total examination isn’t necessary.

Don K
Reply to  Gary Pearse
April 5, 2017 9:19 am

Yes, you probably need to use a grid, but I doubt it’s anywhere near that simple. Most of the reef area will be under varying amounts of water that selectively absorbs longer wavelength light presumably making white surfaces at any depth look bluish. And you will need to distinguish unbleached coral from bleached coral from coral sand from grass from seaweed from algal mats from unvegetated islets from land from God only knows what else. I’m sure it can be done, but I have to wonder how well.

(Caveat, spent a few weeks prowling around fringing reefs in Queensland 50 years ago looking at the inhabitants. But I’m in no way an expert on coral reefs or marine biology.)

john harmsworth
Reply to  Gary Pearse
April 5, 2017 12:54 pm

Some reefs see a lot of fresh water. Some see agricultural runoff. Some are more or less prone to low tides. They are all somewhat unique to their specific latitude and longitude. I doubt that a simple grid sample would do the job adequately. Apparently, eco-activist marine biologists armed with freshly minted government cheques and the latest drone technology can’t figure it out.

Gary Pearse
Reply to  Gary Pearse
April 5, 2017 3:52 pm

Geologically mapping and interpreting a 30 minute (of degree long/lat in the middle of nowhere) sheet by compass, traverse and canoe is a daunting chore, too, but we managed to map all of Canada’s 10million km^2 in about a century! I contributed my share in the 50sand early 60s and then contributed three years worth of coverage of not small tracts of northern Nigeria’s geology as well in the middle sixties, half during a civil war. Later mapping detailed geology in mining exploration projects including logging of tens of thousands of metres od diamond drill core with a hand lens and a notebook.

We used to say that the life work and the living and working conditions of the field geologist would have caused riots in every penitentiary in the world by prisoners facing 10% of the geologists lot. I think I could plan with a bit of advice the traversing of the GBR and might bring an idea or two of my own to it. Although at 80, I might have to do it by skype from the St Jame’s Hotel pub.

April 5, 2017 7:03 am

I used to read Nature when it was the publication likely to have analysis like Jim’s.It seems so strange to see the work on eutrophication and its impact on biomes discarded. It took a lot of effort to get governments around the world to recognize that improper discharge of waste could harm species diversification, and change the fundamental relationships in the ecological microsystems. Assuming, and by that assumption throwing away so much hard won science by a scientist, seems so much worse than anything a non scientist can do from ignorance or purposeful stubbornness.

john harmsworth
Reply to  jfpittman
April 5, 2017 12:55 pm

Same for Scientific American X 10!

April 5, 2017 7:04 am


Can’t thank you enough! This is a really great analysis…so thoughtful and informative. I truly enjoy reading your stuff, as I learn so much about all the various aspects of the subject at hand. One thing I’ve learned over the years, is that when I’m not familiar with a subject, I don’t even know what questions to ask. With the details you present, I at least begin to have an inkling of the variables involved in the choral ecosystem. Thanks again! (Btw, I had dropped a comment about Hughes 2017 in the Tips&Notes page a few weeks ago hoping you’d respond. So, I’m really glad you did!!!)


April 5, 2017 7:05 am

Could the sea level fall also explain the reported mass die-off of coastal mangroves in the Gulf of Carpentaria? The warmists’ rush to invoke climate change (drought and warmer sea temperatures) did not seem to explain the phenomenon. Lack of sea water along a long coast seems more plausible than lack of run off from well spaced river mouths.

Reply to  Stanley
April 5, 2017 4:49 pm

“Could the sea level fall also explain the reported mass die-off of coastal mangroves … ”
Yes it could. I have personally inspected mangrove die-off that was most likely caused by a minor change in natural sedimentation around it.The people responsible for the area carefully washed and pumped the sediment away to higher ground, because they knew they would be blamed for the incident.
It is usually a natural process; mangroves retain sediment which eventually rises enough to become a dune and secondary colonising plants take over.
Mangroves don’t have the same media impact as coral. They are humming with life but are also a bubbling stinking mass of decay. They trap debris, act as nurseries for juvenile fish etc. Mangroves will actually walk, albeit very slowly. Could be moving with the sand bars maybe, but there is one in front of my place that has walked.

Tom Halla
April 5, 2017 7:14 am

Very interesting that changes in sea level are a well known effect of ENSO, but the “researchers” did not take it into account. I guess they will claim it was the CO2 in the open air that killed the coral.

Reply to  Tom Halla
April 5, 2017 9:20 am

We’ve been told that CO2 is so powerful that it completely swamps all other natural causes.
So why bother investigating anything other than CO2?

April 5, 2017 7:15 am

The Man Of Steele produces work that educates. What more should anyone ask of a scientist and teacher.

As to the corals let me suggest that we find one that is particularly resilient and designate it a Shakhanovite Coral. We can then roll out a comprehensive propaganda effort exhorting all corals to follow it’s example. This would
have the same effect as public policy based on much of current climate science.

April 5, 2017 7:50 am

The Hughes paper is only the latest in a long series of catastrophic reports on the GBR from the same group of researchers at the ARC Centre of Excellence for Coral Reef Studies. This outfit represents the “endless doom” side of the Great Barrier Reef Wars in Australian reef science.

Both the Australian Institute of Marine Science and the Great Barrier Reef Marine Park Authority have since issued statements attempting to correct Hughes et al. 2017. By the end of summer we will see new papers modifying the outlook towards something more real — and by next year, papers showing the magnificent resilience of the GBR to recover from this latest bleaching event.

Oddly, as the reef recovers, no one will mention that CO2 concentrations did not have to fall for this to occur.

Reply to  Kip Hansen
April 5, 2017 9:04 am

” the ARC Centre of Excellence for Coral Reef Studies”

Yet another of these bullshit “Centres of Excellence”. Who are they trying to con ? If you were a centre of excellence you would not need to put it on the letter head. Do Yale and Harvard have to put “excellence” in their names? No, because they ARE centres of excellence not bullshit merchants trying to dress politics as science.

Reply to  Greg
April 6, 2017 5:16 am

A while back I taped over the sign on the washroom in my academic department with the label “Center for Sanitation Excellence.” I expected it to spark outrage and be removed right away, but it drew giggles and survived a couple of years. Apparently no one takes this marketing BS seriously.

Reply to  Kip Hansen
April 5, 2017 4:47 pm


Recently James Cook University’s “ARC Centre of Excellence for Coral Reef Studies” (JCU-ARCCECRS) and the Reef and Rainforest Research Centre (RRRC) went public with a bid for millions of taxpayer dollars to set up large-scale pumping stations to pump cold water up onto the reef flat.

It was so intensely annoying that I started a change.org petition to get them stopped. After two weeks it has 375 signatures. https://www.change.org/p/steven-miles-save-the-great-barrier-reef-from-industrial-scale-experiments

I’ll paste in the petition’s body text below. I just wish I’d had read Jim’s essay before I wrote it…

Cheers, Beliaik

Should people who don’t properly understand the Great Barrier Reef be allowed to interfere with it on a massive scale?

Sign this petition to stop industrial-scale experimentation on the reef! Say no to electric currents! Say no to giant plastic shade cloths! Say no to genetically engineered “Frankencoral”! Say no to cold-water pumping!

James Cook University’s “ARC Centre of Excellence for Coral Reef Studies” (JCU-ARCCECRS) and the Reef and Rainforest Research Centre (RRRC) have bombarded us with stories of impending reef death for years. They are motivated to do so because their livelihoods depend on them finding the next scary story.

None of their prophecies of doom have come true and it is fairly clear that they don’t have a full and meaningful understanding of their subject.

Revelations from scientists elsewhere (such as coral’s kissing behaviour, the healthy coral reef under the Amazon mud-plume and the effects of oxybenzone from sunscreen) always come as a surprise to JCU-ARCCECRS and RRRC.

JCU-ARCCECRS and RRRC love to link coral bleaching to the carbon dioxide emissions from humans burning coal – but they have never provided empirical evidence to support their “belief”.

On March 22, 2017, they said they want to pump cold water from the depths into the naturally warm coral reef environment.

They must be stopped because they can’t be trusted to get it right. It is highly possible they will do more harm than good.

JCU-ARCCECRS and RRRC don’t seem to look for other sources of heat that may have warmed the waters of the Coral Sea other than the alleged CO2 greenhouse effect.

JCU-ARCCECRS and RRRC don’t discuss the influence of the recent El Nino event on Coral Sea water temperatures – El Nino is an entirely natural cycle with no connection to humans burning fossil fuels.

The bleached areas of the GBR are bathed by the South Equatorial Current, which is heated by sea-floor volcanicity in the Vanuatu-Solomons region – where some of the world’s most active and spectacular volcanoes are found. But JCU-ARCCECRS and RRRC don’t monitor heat from that source.

The Vanuatu-Solomons volcanic zone has many sea-floor hydrothermal vents that release sulphur compounds that are toxic to the microorganisms that are the basis of the reef’s food chain; but JCU-ARCCECRS and RRRC don’t monitor those compounds’ effects on coral.

Oxybenzone, an ingredient in many sunscreens worn by reef researchers and tourists alike, is highly toxic to coral, even in minute quantities. But JCU-ARCCECRS and RRRC don’t study that either.

Coral is the ultimate survivor from the past 400 million years of ever-changing climate and multiple mass-extinction events, but JCU-ARCCECRS and RRRC don’t explain why it should suddenly be hyper-sensitive to minor water temperature changes.

The ability of coral to expel and replace symbionts is an evolutionary superpower that other species can only dream of, but JCU-ARCCECRS and RRRC never discuss that.

JCU-ARCCECRS and RRRC don’t mention that coral can live in waters much hotter than ours, such as the Middle-East, and much colder as well, like New Zealand.

JCU-ARCCECRS and RRRC don’t explain how coral seems to be OK in blazing hot sun at low tide, either in shallow, easily-heated pools or exposed to the air. Nor how the same species will grow in slightly deeper water where it’s colder.

JCU-ARCCECRS and RRRC are always punishing farmers over terrestrial sediments but they were as surprised as anybody when it was discovered there was a healthy coral reef living happily under the permanent mud-plume of the Amazon River.

JCU-ARCCECRS and RRRC have taken to flying over the reef to determine the extent of coral “mortality” – but they should know that when coral expels it’s symbionts it’s flesh becomes transparent and only a close examination will determine whether it is alive or dead.

JCU-ARCCECRS and RRRC can’t explain how the man-made carbon dioxide molecules reflecting infrared radiation back down to the sea are able to heat the molecule-thick surface layer of the water without evaporation immediately re-releasing that heat energy to the air. They seem unaware that infrared radiation cannot penetrate water.

JCU-ARCCECRS and RRRC promote scandalously weak claims as if they were somehow supported by empirical evidence and were to be accepted as fact – to the extent that they want $9 million taxpayer dollars to pump cold water onto the reef.

Steven Miles, please pour cold water on these scientists. We say “no” to industrial-scale interference with our Reef!


Reply to  Beliaik
April 5, 2017 5:44 pm

Beliak ==> There is some information here on the CoTS problem.

Reply to  Beliaik
April 5, 2017 6:13 pm


GBRMPA has rearranged its website and broken your link to the COTS research. Searching COTS there gives 700 results. Which article did you mean?

GBRMPA isn’t at all trusted by Far North Queenslanders. They’re just another bunch of kool-aid-drinking, government-funded zealots.

Thanks, Beliaik

Reply to  Beliaik
April 5, 2017 8:37 pm

Beliak ==> There is some information Try this link

April 5, 2017 7:57 am

It’s very difficult to prove to the general public that CO2 isn’t causing warming, but it’s much easier to show that reefs aren’t dying from “global warming.” For example, see here http://www.icriforum.org/caribbeanreport. Organizations that monitor reef health know what the real and immediate threats to reefs are, and it isn’t global warming. It’s pollution and overfishing.

I find that when I talk to people about CO2 they’re easily lost when I get into even a little bit of the science; they have no idea if I know what I’m talking about or if I’m blowing smoke. When I talk about reefs, though, I can explain pretty easily that reef deaths aren’t due to global warming, and I have the “authority” of reef organizations to back me up. That authority is important.

Something to think about, in light of the recent post about “winning the war” on climate science. Maybe we should be talking about reefs first.

April 5, 2017 7:59 am

Didn’t the crown of thorns starfish doom the entire reef in the 1960’s ? At least that is what we were taught in school. Must be resilient or something.

Reply to  Doug
April 5, 2017 9:12 am

Doug ==> Crown of Thorns “outbreaks” are still serious threats on the reefs of Australia. There are efforts to control them in areas of serious outbreak.

Reply to  Kip Hansen
April 5, 2017 4:55 pm


Females COTS produce 120 million offspring per season each. That suggests COTS have evolved to counter heavy juvenile losses due to predation or some other factor. Shouldn’t researchers be trying to find out where all those unsuccessful juveniles disappear to? Perhaps restoring numbers of a suitable predator would solve the COTS problem.

Cheers, Beliaik

Reply to  Kip Hansen
April 6, 2017 6:38 am

Vinegar?? Why is that better than pumping cold water in?

Stop the runoff, don’t add to it.


Reply to  Kip Hansen
April 6, 2017 8:13 am

Glenn ==> The vinegar is not added to the sea water to control CoTS….it is injected into individual CoTS by a diver — killing that one starfish within 48 hours, but not making the [dead] starfish body poisonous to other reef inhabitants that then eat the dead starfish. see https://www.jcu.edu.au/news/releases/2015/september/new-weapon-against-the-reef-eaters.

Horace Jason Oxboggle
Reply to  Kip Hansen
April 6, 2017 2:32 pm

My theory is that bleaching on the Great Barrier Reef is caused by the mating of Crown of Thorns Starfish with cane toads. Hell, it’s as plausible as some others!

Reply to  Kip Hansen
April 7, 2017 8:50 am

Ya never know…..

April 5, 2017 9:14 am

Very good article Jim but way too long. My attention deficiency syndrome kicked in about half way down.

One thing to note about tidal forces: in both 1998 and 2016 the perigee full moon fell within a few days of the vernal equinox and an eclipse event. This means perfect alignment of sun and moon over the equator with the moon at its closest point and thus maximum tide raising forces.

Be careful with altimetry data, many datasets include in ‘inverse barometer correction’ which in the case of high pressure system over the region would artificially bring the pretend water level back up.

Reply to  Greg
April 5, 2017 9:35 pm

Your attention span is your problem, not Jims.

Reply to  toorightmate
April 8, 2017 11:30 pm

I thought it a great article and had no problem with length. OH’s interruptions caused more trouble!

Roger Knights
Reply to  Greg
April 6, 2017 1:20 am

I agree that it could have been more concise if there had been less repetition.
(Excellent otherwise.)

April 5, 2017 9:52 am

What is the point of having a Liberal government in Austrailia or a Republican one in the USA if they pursue bad policy based on lousy science. Does Mr. Turnbull have an answer? We found ours last go round. Best Wishes to our Aussie friends.

April 5, 2017 11:18 am

Reblogged this on Wolsten and commented:
An excellent analysis of Hughes 2017. Probably not surprising that the impact of falling sea levels was ignored when the prevailing dogma has them rising inexorably.

Mark - Helsinki
April 5, 2017 1:02 pm

SPS corals which make up most of the corals you see in these bleach images are very sensitive to light spectrum changes and falling sea level would cause such a problem which the corals naturally adjust to.

April 5, 2017 1:18 pm

Should not all people responsible for approving grants for “scientific research” have to show that they understand that “correlation does not prove causation”?

James at 48
April 5, 2017 1:35 pm

Doesn’t El Nino also lower the SSTs in that area?

April 5, 2017 1:39 pm

One of my MSc students undertook a research project a decade ago looking at managing the coral reef fish resources for the Federated States of Micronesia. One of the local concerns was about the impacts of global warming on the coral reefs. The focus was on bleaching due to elevated temperatures, particularly following a severe event in 1998. We compiled all available data for Pohnpei on ocean and atmospheric conditions and bleaching events.
The students analysis showed that severe bleaching coincided with a shift in dominant wind direction with an associated change in wave patterns, a drop in sea surface and air temperatures, a decrease in rainfall and a large decrease in sea level (30 cm below MSL). Our conclusion was that the bleaching was primarily due to sea level fall exposing the upper reef to the atmosphere and UV. It was not a well received conclusion.

April 5, 2017 2:06 pm

A thought for Jim Steele to follow; The Australian tectonic plate is moving towards New Guinea at around 24mm per year and has been doing so since it broke away from Antarctica. As it does so, it is rising against the northern plate so that the Torres Strait is one of the shallowest seaways in the world. This movement could cause the sea levels to fall the further north you go. If you look at the Great Barrier Reef Marine Park Authority colour coded chart, this seems to be represented with most bleaching to the north and least to the south.
It would be interesting to see if the sea levels at the various monitoring stations reflect this.

Reply to  Col
April 5, 2017 3:06 pm

As you know, technically southern New Guinea is on the Australian Plate. This big, continental plate meets a bunch of little plates in northern New Guinea, forming the Highlands, and the Bismarck arc, site of some big, active volcanoes.

Curious George
April 5, 2017 2:47 pm

“It is puzzling why the recent 2017 publication in Nature, Global Warming And Recurrent Mass Bleaching Of Corals by Hughes et al. ignored the most critical factor affecting the 2016 severe bleaching along the northern Great Barrier Reef – the regional fall in sea level ..” Not puzzling at all. The SEA LEVEL RISE is the sacred cow of alarmism. The FALL, even a regional one, is extremely inconvenient.

April 5, 2017 3:54 pm

I weep with you, the overwhelming incompetence of virtually every “scientist” ??? involved in promoting AGW routinely stuns me. Thank you for your most insightful article on corals

Peter Ridd
April 5, 2017 4:20 pm

you may be interested that there was a mass mortality of mangroves in the Gulf of Carpentaria last year also caused in part by a temporary drop in sea level associated with El Nino. It was a huge event. see link below or I can send you the original paper.
I should add that I have looked at many of the videos of the bleaching taken from aircraft and it is difficult to see how the figures that Hughes presents are credible. In addition a parallel survey of GBR bleaching done by tourist operators indicated far lower levels than reported by Hughes team.
It looks like another example of results we cannot trust.
Peter Ridd
James Cook University

Jim Steele
Reply to  Peter Ridd
April 6, 2017 8:51 am

Hi Peter,

The effect of lower sea level on mangroves is definitely interesting. If you could send me the original paper I would be grateful. jsteele@sfsu.edu. Thanks

Can you publishing/blog a comparison of Hghes’ estimates to the others?

John Gorter
April 5, 2017 5:41 pm

Great article Jim.



April 5, 2017 6:10 pm

Just bought his book. People who can think critically need to be encouraged IMHO.

April 5, 2017 6:20 pm

Its always refreshing to see a scientific article which looks at the data first, and then makes hypotheses second. There is not a lot of that approach in the climate fraternity. It even more refreshing when that study explodes a dogma well past its use-by date.

On a scientific point, a 120m sea level rise in the last 20ky after the last ice age peak means that all current corals down to 120m didnt exist 20k years ago, and the shallower colonies are very young.

I have a feeling that corals dog the current sea level and live/die as MSL moves. Isotopic age studies on corals must be particularly illuminating.

April 5, 2017 8:01 pm

Oh my goodness . . this is like a WMD . . Yer a real badass Mr. Steele ; )

Peter s
April 5, 2017 9:11 pm

I have snorkeled out there twice and it is breathtaking as you dive down deeper. The GBR is a living thing. In ideal conditions the coral grows wider and higher until it gets close to the surface where it is exposed to the sun more often during low tide. Naturally its vivid colours will become bleached. But of course there is no funding in this sort of story.

Bill Parsons
April 5, 2017 11:11 pm

Have there been studies of coral exposure on the eastern pacific coastal areas (Baja, or wherever coral is found)? My understanding is the ocean sloshes back the other way after an El Nino – some say as much as 9″ decline. So…

Do La Nina periods leave corals along the western Americas exposed? If so, perhaps there is complementary bleaching in opposition to the bleaching in the western pacific.

Anyway, thanks Jim Steele for another intriguing science piece. Seems like a strong case to explain surface bleaching.

Bill Parsons
April 5, 2017 11:40 pm


Photo Caption:
An exposed coral reef in Panamá. Exposures during La Niña events, such as this one in 2010, kill the corals en masse. Frequent La Niña-like events helped drive a long-term collapse of reef ecosystems across the Pacific, which began around 4000 years ago and lasted 2500 years.

April 6, 2017 5:04 am

So sea level rise is levelling off and the Climagesterium is trying to conceal the fact.
This could get interesting.

April 6, 2017 5:56 am

Excellent article. Duly bookmarked.

The information I think the public needs includes the alternative causes for a particular effect. The AGW fraternity are happy to push the “warming causes everything” approach. It is only when you have an idea of the other things besides warming that can have an effect that you can counter their arguments successfully. This article provided that information. Thank you.

April 6, 2017 6:15 am

Steele ==> Very nice. And you are so right — no one has heretofore even mentioned sea level in relation to coral bleaching on the GBR — no one.

They also fail to mention that it is almost exclusively near-surface corals that are affected by bleaching events — those at (what I call) snorkel-depths — less than 15 meters. Not only do most tropical reefs include vast areas deeper than 20 meters (60 feet), but huge areas of deep sea reefs exist in all oceans — which can be found as deep as 2,000 feet.

April 6, 2017 2:42 pm

Very thorough article!
Thank you

Jim Steele
April 6, 2017 6:25 pm

as Dr Ridd reported researchers have similarly attributed the die off of mangroves along the Gulf of Carpentaria in northern Australia to a month long drop of sea level of 20 cm along with the warming effects of El Nino.


John Kelly
April 8, 2017 10:41 pm

As someone who lives in Cairns, the main GBR tourist city, it was very disappointing to see the immense media coverage that Hughes et al received. It did a lot of damage to tourism. About the same time as the bleaching event I read a very brief news story of mass mortality of mangrove tress on the south-east corner of the Gulf of Carpentaria, i.e. a location about the same latitude as Cairns and the northern section of the GBR. The reason given for the mortality was extreme low sea levels. I’m sure that if a non-scientist (although I am an engineer) had seen this report that Hughes et al would have also seen this report and then presumably they choose to ignore it. There is a tidal gauge at my local pier (Palm Cove) so its not as it sea level information was not available to Hughes et al. This is a very popular pier with locals in northern Cairns and is only a few kilometres from JCU, so Hughes and his colleagues will know of its existence.

Science is a truly wonderful thing but politically adulterated science is abominable.

Kent Noonan
April 10, 2017 9:55 am

To Jim Steele, Guardian has an April 9 article declaring another bleaching event in 2017. No mention of falling sea level. Includes aerial photos of coral exposed above the water, and bleaching primarily on the tops of the coral. My small local paper also put it on the front page today, calling it “terminal stage”.
It would be wonderful if this sea level paper and your article could be quickly updated to include and/or refute the present claims. This appears to be propaganda if the original authors knowingly ignore data that refuted last years claims, and double down this year.

Reply to  Kent Noonan
April 10, 2017 11:23 am

And, the same on the BBC news this evening with an interview of Hughes and, what seemed to me, a nervous woman from, who I think was, from Bristol Uni being a little more cautious.

April 10, 2017 3:19 pm

JS A well worked piece. Most informative indeed. Thank you for your efforts. You have set me quite a task to read and understand all of the references.

Today the BBC fawned all over Huges in a piece which is pure warmist propaganda. http://www.bbc.co.uk/news/world-australia-39524196 The standard of writing put out by BBC on climate seemingly without any editorial control is concerningly poor and biased, doubly so for an organization renowned for quality and impartiality. The common denominator is always to promote the anthropogenic global warming/climatechange/belief system. A drug to keep the believers of the zealots of the “Western man is responsible for everything bad in the world” religion in line and in a state of frenzy.

Also is it just me of does it appear that anything resembling research which includes support for the claim that man = warming=climate change=catastrophe does not appear to be subject to the same standard of rigorous peer review or post publishing public critique as would be the case in any other branch of the sciences? Basing any piece no matter how flawed on the premise that “Man=CO2=EVIL” seems to guarantee maximum exposure in the mainstream media while being seemingly immune to the usual consequences of “bad work exposed”.Flawed work produced either willfully or incompetently is certainly no impediment to funding or career as long as it promotes the religion! I am not a conspiracy theorist but the frequency with which bad research on this subject despite being shown to be flawed continues to be promoted, seemingly immune to critical question suggests some very powerful forces are at work. JS

April 11, 2017 8:30 pm

Jim Steele, the bird call expert, says: “widescale bleaching not worrisome.” That is one of the dumbest statements I have ever read. The fact that so many sheep believe in this fiction is sad. Bleached corals expel algae that provide 90% of their food. Bleached corals do not grow, they do not reproduce, they have lost their food source and energy. Starving not worrisome? The fact that the denialists are so hopeful that widescale bleaching is not glaring obvious example of the destruction of climate change that they prop up Jim Steele, a nature walk expert, is unseemly. He is a charlatan, and pretending that the Great Barrier Reef is not bleaching due to anything but climate change is poppycock.

[NOTE: according to his Facebook page (linked in his response name section) Tripp has an MBA from Duke University and is the “Director of Operations at Coral Restoration Foundation International”. Looking at that website’s staff directory, https://coralrestoration.org/about/meet-the-team/ his description reads:

Tripp Funderburk
Policy Director

Tripp Funderburk is a PADI certified Divemaster and has received SSI Ecological Diver Recognition for Coral Restoration Theory and Methods, Coral Nursery Construction and Maintenance, and Coral Abundance and Health Assessment. Before joining Coral Restoration Foundation, Tripp worked in public policy in Washington, DC, including eight years as a legislative assistant to US Representative Bob Livingston. Tripp served as staff on both the House Appropriations and the House Administration Committees. Tripp also worked in government relations for The Washington Group and The Livingston Group where he represented Fortune 500 companies, trade associations, and non-profit organizations. Tripp received his M.B.A. from Duke University’s Fuqua School of Business and his undergraduate degree in economics from the University of Virginia.

So it seems Tripp is just an policy/politics/business management guy with an interest in diving that found a job after his patron, Rep Bob Livington, imploded and resigned after a series of adulterous affairs made him national news. Other than surroundign himself with people who on this coral foundation, he appears to have no scientific training, unlike Jim Steele, otherwise he would not have to resort to to ad hom attacks on Mr. Steele’s training, and no other substantial arguments. Given coral is his sole source of employment, this famous quote is applicable to Tripp

“It is difficult to get a man to understand something, when his salary depends upon his not understanding it!” – Upton Sinclair, 1935

– Anthony Watts]

Jim Steele
Reply to  Tripp Funderburk
April 13, 2017 8:30 am

Trip is now calling my house, dropping F bombs and launching insulting rants.

I really like what Nedimyer and the Coral Restoration Foundation International are doing. Trip is a business major overseeing their operations. The tremendous loss of staghorn and other Acropora sp coral in the Caribbean due to disease and predation makes it difficult for those species to recover because they reproduce mostly by fragmentation. A complete loss of staghorn on a reef usually means that reef needs to be colonized from a fragment from another reef. Coral Restoration Foundation collects living staghorns breaks them up into many smaller pieces and grows them and then replants them.

It would be a shame if Trip’s low life behavior threatens the foundation’s good work. Perhaps a few emails or calls to the foundation would alert them to Trip’s detrimental behavior

(305) 453-7030 info@coralrestoration.org

Reply to  Jim Steele
April 13, 2017 2:27 pm

Thanks for this info, Jim. I just sent this to the Coral Restoration Foundation. Cheers, Beliaik, FNQ, Australia

An ethical question for your CEO or Board of Directors


As someone who lives adjacent to the Great Barrier Reef I’m concerned about reef health and the damaging effects of faulty ideologically-driven pseudo-science on effective marine ecosystem conservation.

Particularly nonsensical non-science is regularly emitted by James Cook University’s pompously named “ARC Centre for Excellence for Coral Reef Studies” and the (Australian) Climate Council.

The Australian mainstream media slavishly follow the alarmist meme – to the detriment of genuine and meaningful understanding of our precious marine ecosystems.

To get alternate views that better align with observed reality one has to go to science blogs – with one of the better ones being Anthony Watt’s excellent Watts Up With That.

Jim Steele recently posted an outstanding piece on WUWT about how El Nino-driven sea level variations contributed to recent coral bleaching on the GBR.

And this brings me to the reason for my message to you today.

It is very disturbing to read Jim Steele’s comment on WUWT that one Tripp Funderburk from the Coral Restoration Foundation is behaving completely unprofessionally and unacceptably towards him in response to that article.


Steele says, “Trip is now calling my house, dropping F bombs and launching insulting rants.”.

Would you mind explaining how Funderburk’s reported behaviour aligns with your organisation’s values?

Reply to  Jim Steele
April 13, 2017 8:41 pm

Jim I am very sorry you had to put up with such childish behaviour. I thought it was an excellent article and am going to be very interested in the response from Beliak’s correspondence with CSF.

Jim Steele
Reply to  Tripp Funderburk
April 13, 2017 8:37 am

Trip dishonestly cherry-picks a few words from one sentence that said, “However bleaching without mortality is not a worrisome event no matter how extensive. Rates of mortality and recovery are more important indices of reef health.”

If bleaching persists then mortality will follow. If bleaching is temporary, then observation after observation reports recovery to pre-bleaching conditions and every thing Trip is worried about is no longer a problem. Not being a biologist such simple facts elude him.

April 11, 2017 9:32 pm

Reblogged this on Climatism and commented:
“shallow coral were increasingly vulnerable to deadly desiccation during more extreme sea level drops when warm waters slosh toward the Americas during an El Niño.”

A must read to educate and prevent further misleading great barrier reef hysteria and subsequent ad-hoc and misguided Coral conservation policies…

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