I have already posted twice on coral reefs, but skirted round the article on Coral Alarmism by Geoff Price at his own blog on April 2nd 2018, reposted at ATTP eleven months later. By reposting this article Prof Ken Rice has shown how derisory is the evidence for global warming being the cause of increasing coral bleaching. 

Checking the sources that Price gives for (a) evidence of global warming (b) media sources of coral bleaching reveal there is no unambiguous underlying evidence to make a persuasive case  linking of one with the other. Further. the major peer review paper that Price cites finds that changes in severe coral bleaching events are not explained by global warming.

Evidence of global warming related to coral reefs

The first issue I want to deal with is the evidence that Price presents for the increase in coral bleaching being due to global warming.

Price first states the dogma

In our window of time here and on our watch, we’re observing the unfolding collapse of global coral reef cover – the largest living structures on the planet, relatively priceless in terms of human and economic value, and stunningly beautiful – due to human-induced stresses, now most prominently from human-caused global anthropogenic (greenhouse) warming of the oceans.

The claim of human induced warming is not backed up by any evidence.  That global average temperatures have been rising for well over a century  does not mean that this was human-induced. It could be natural or just some random cyclical cycle in a chaotic complex system, or some combination of all three. The evidence of warming oceans is the NOAA data of estimated increase in ocean heat content from 1960. There are a number of things wrong with this approach. The data period is only from 1960; heat stress in corals is from the amount of temperature rise; and the data is for 0-700m down, whilst most corals reside just a few meters below the surface. A much better measure is the sea surface temperature data records, which measures temperature just below the surface.

Below is the HADCRUT4 land and ocean anomalies temperature anomalies that I charted last year.

 

 

Crucially, the HADSST3 ocean warming data shows a similar global average temperature increase in the early twentieth century as the post 1975 warming. Both were about 0.5C, a value likely much less than the seasonal sea surface temperature change. Also, the rise in GHG gases – especially of CO2 – is much more post 1950 than from 1800 to 1940. The data does not support the idea that all warming is human-caused, unless global warming is caused by Mother Gaia anticipating the rise in CO2 levels.

Even then, then rise in global sea surface temperatures is not an indication of warming in a particular area. The Great Barrier Reef, for instance has shown little or no warming since 1980. From my previous post, observed major bleaching events do not correspond to any rise in warming, or any increase in extreme temperatures.

Media Sources do not support hypothesis

Even if Geoff Price cannot provide proper evidence of the rise in average temperatures that coral reefs are experiencing, at least he could provide credible scientific evidence of the link between warming and increase in coral bleaching. Price states

Some articles in major media break through, e.g. Global Warming’s Toll on Coral Reefs: As if They’re ‘Ravaged by War’, though the impact on public awareness and policy action remains low. The impact is global including the Great Barrier Reef (GBR), Japan, the South Pacific, Hawaii, the Florida keys, and Belize.

Rather than presenting empirical evidence, or at least scientific articles, relating increased coral reef bleaching to global warming, Price bizarrely “quotes” from various media sources. To show how bizzare, I have made some notes of the sources,

As if “Ravaged by War”

The “Ravaged by War” article in the New York Times of Jan 4 2018. At the start of the article is stated “large-scale coral bleaching events……were virtually unheard-of before the 1980s“, whereas later on is stated ”before 1982-3, mass bleaching events across wide areas were nonexistent.”  The perceived lack of bleaching before the 1980s is changed into a fact. The lack of perception is due to lack of wide-scale research. But even 1982-3 as the first year of reporting of mass bleaching is contradicted by Figure 1c in Glynn 1993, reference 3 in the Hughes et al 2018 paper that prompted the NYT article. 1978 and 1979 have far more recorded mass coral mortalities than 1982 and 1993.

Evidence of global bleaching

The link is to a page of high quality pictures of coral bleaching from around the world. The rise of digital photography, and the increase in the numbers of people diving reefs with cameras in the last twenty years is evidence observation bias not of real increase. In the past, lack of wide-scale human perception does not mean the issue was not there.

Great Barrier Reef Bleaching

From the UK Independent April 20 2016 is the headline “Great Barrier Reef: Half of natural wonder is ‘dead or dying’ and it is on the brink of extinction, scientists say“.

The event is partly being caused by the strong El Nino weather system that has swept across the world in the last year. But global warming is the underlying cause, say scientists, and so the bleaching and death is likely to continue.

“We’ve never seen anything like this scale of bleaching before. In the northern Great Barrier Reef, it’s like 10 cyclones have come ashore all at once,” said Professor Terry Hughes, conveyor of the National Coral Bleaching Taskforce, 

The claim that global warming is the underlying cause of the bleaching is not attributed to any one person, or group. Prof Terry Hughes only makes a statement about the current state of affairs not being observed before, not that, in reality, it is unprecedented. Again a difference between perceptions and underlying reality.

Japan

The Japanese study is from an environmentalist website Down to Earth on January 13 2017. It states

Experts have, for quite a while now, believed that corals are among the most susceptible organisms to climate change. In fact, the world has already lost 30-40 per cent of its total documented coral cover.

According to the ministry’s estimate, 70 per cent of the Sekisei lagoon in Okinawa had been killed due to bleaching, which occurs when unusually warm water forces coral to expel the algae living in their tissues. Unless water temperatures quickly return to normal, the coral eventually dies from lack of nutrition.

Based on the survey done on 35 locations in Japan’s southernmost reaches from November to December 2016, the ministry observed that the plight of the reef has become “extremely serious” in recent years.

According to a Japanese media, the dead coral has now turned dark brown and is now covered with algae. It also revealed that the average sea surface temperature between June and August 2016 in the southern part of the Okinawa island chain was 30.1°C—one to two degrees warmer than usual. According to the Japan meteorological agency, it was also the highest average temperature since records began in 1982.

There is no link to the original source and from the statement the article is probably relying on media sources in English. Therefore there is no way of verifying whether the claims are due to warming. I would assume that the authors, like myself, do not speak Japanese, and the script is incomprehensible to them. Further, the article highlights just one of 35 locations in the Japanese study. This should be a signal that the cause of that extreme example of coral bleaching is more than just extreme temperatures.

Searching “Sekisei Lagoon” I come up with lots of returns, mostly about Coral bleaching. There was one is a short 2017 article at the Japanese Ministry of Environment website, and sponsored by them. The second paragraph states

(C)orals in the (Sekisei) Lagoon have extensively diminished since park designation because of various reasons: terrestrial runoffs of red clay and wastewater; coral bleaching due to high water temperatures; and outbreaks of the predatory crown-of-thorns starfish (Acanthaster planci). Initial efforts have been made to reduce terrestrial runoffs to help the natural recovery of coral ecosystem health. Studies on coral distribution and techniques for reef rehabilitation are also in progress.

It is does not look like global warming in the sole cause of the excessive coral bleaching in Sekisei Lagoon. It is also local human factors and a large predator. A little research of crown-of-thorns starfish reveals that sudden increases in populations are poorly understood and that it is also found on the Great Barrier Reef. Acanthaster planci has a number of predators, the lack of which might indicate reasons for the outbreaks.

Other Media Sources

The South Pacific source is a blog post from March 2016 on American Samoan Reefs, a small part of the total extent of islands across the vast region. It is about coral bleaching being on hold, but there is an alert due to recent abnormally high temperatures. If bleaching did follow it would have been due to the El Nino event, which caused abnormally high average temperatures globally.

The Hawaii source, does not give a link to the peer reviewed article on which it is based. Looking at the article, it is (a) based on surveys in 2014 and 2015, but with no data on historical events (b) claims that elevated temperatures were present in Hawaii, (but does not show that the global average temperature were not elevated (c) provides no evidence of comparative surveys in the past to show the issue has got worst. In the first sentence of the introduction it is implied that the entire 0.9 °C in average SSTs is due to rise in GHGs, a totally unsupportable statement. Peer J’s boasted rapid peer review process has failed to pick up on this,

The Florida Keys reference is a Washington Post article of June 25 2017 about how loss of the coral reefs through temperature rise will impact on tourism. It assumes that temperature rise is the sole course of coral reef loss.

Finally the Belize article a New York Times opinion piece from July 6 2017, about a researcher visiting the coral reefs. There is no data provided for either local warming or trends in bleaching.

Hughes et al 2018

The major scientific article that Price refers to is

Spatial and temporal patterns of mass bleaching of corals in the Anthropocene DOI: 10.1126/science.aan8048 . (Hughes et al 2018) 

Unusually this paper is open access. I quite like the attempt to reduce the observation bias when they state

Here we compiled de novo the history of recurrent bleaching from 1980 to 2016 for 100 globally distributed coral reef locations in 54 countries using a standardized protocol to examine patterns in the timing, recurrence, and intensity of bleaching episodes, including the latest global bleaching event from 2015 to 2016.

This does not eliminate the observation bias, but will certainly lesson the bias. They then make the observation

Since 1980, 58% of severe bleaching events have been recorded during four strong El Niño periods (1982–1983, 1997–1998, 2009–2010, and 2015–2016) (Fig. 2A), with the remaining 42% occurring during hot summers in other ENSO phases.

Considering that 2017 was also a severe bleaching events and global average temperatures were higher than in the 2015 El Nino year and in 2018, not to state it is an El Nino year is a maybe a bit dubious. Even so, on this basis El Nino free years are runs of 13, 10 and 4. This is not unlike the statement in the abstract

The median return time between pairs of severe bleaching events has diminished steadily since 1980 and is now only 6 years.

The paper makes no direct claims about the increase in observed coral bleaching being related to global warming. But This is because the data does not show this. Supplementary data figure 4 tests the relationship between the number of severe coral bleaching events per location and warming at that location across four regions.

For Australia R² = 0.0001. That is zero. Better results can be achieved from two random unrelated data sets.
The best relationship is for the West Atlantic – mostly the Caribbean. That is R² = 0.0939. The downward slope implies a negative relationship.  But still less than 10% of the variation in severe bleaching events is explained by rising temperatures.

Figure 2A of the Supplementary materials I also find interesting in the context of Jaime Jessop’s contention that coral bleaching is related to El Ninos.

Note that this is cumulative recorded severe bleaching events. The relative size of individual years is from the increase in that year.
For Australasia, the three standout years are 1998, 2010 and 2016/2017. These are El Nino years, confirming Jaime’s hypothesus.
For the West Atlantic there were also an unusual number of severe bleaching events in 1995 and 2005. No El Ninos there, but 2005 saw a record number of hurricanes in the area, and 1995 also saw an unusually high number including Hurricane Andrew, the last category 5 to make landfall in the USA. Although excess heat might be the principal cause of stress in coral reefs, I am sure they might also get stressed by severe storms, with the accompanying storm surges.
If severe storms can lead to bleaching there is a problem with observation of bleaching. From Heron et al 2016 we learn that since the 1990s satellites have made twice-weekly recording of surface temperatures are 0.5 degree grids (about 50km), then comparing with the SST data to detect unusual runs of DHWs. Since 2015, a new product was launched with just 5km grids. It is then left to some intrepid scientists to go out in a boat, dive down and take samples. If severe storms do not have unusually high temperatures, then there will be no alerts of bleaching, so unless there are other attempts to observe, this will not be picked up, or could be picked up a short while later after an episode of unusual warming. Before the 1990s, there was no such over-all detection system, and likely much less researchers. Many of the bleaching events occurring before 1990 may not have been picked up, or if they were, there may have been less ability to define that events as major.

Concluding Comments

By re-posting a dogmatic article ATTP has done a service to climate scepticism. Laying out a very bad, but well-referenced, case for global warming causing increased coral reef bleaching shows the inadequacies of that case. Where long periods of data collated on a consistent basis is used there is no correlation. Further, increasing observed frequency of bleaching events since is mostly due El Nino events being closer together, whilst the increase in observed bleaching can be accounted for by the greatly improved methods of detection and the resources put into observing, which are many times what they were a few decades ago.

Geoff Price’s method of presenting the opinions of others, rather than focusing on the underlying data that supports the conjecture, is something in common with ATTP and others of the climate community. When checked, the fail to connect with any underlying reality.

There is a rider to be made. The case for global warming is very poor by the traditional scientific methods of confronting conjectures with evidence of the natural world, and letting such evidence being the ultimate arbiter of that conjecture. From the consensus viewpoint popular today it is collective opinion that is the arbiter. The above is from the former point of view, which means from the latter view this is misinformation.