Inconvenient study: La Niña killed coral reefs 4100 years ago and lasted over two millennia

From Georgia Tech and the “it’s your SUV that’s killing the coral reefs today, why can’t you get that through your head” department comes this inconvenient study.

La Nina-like conditions associated with 2,500-year-long shutdown of coral reef growth

A dead Pocillopora reef in Pacific Panamá. This image of interrupted reef growth represents what reefs throughout Pacific Panamá may have looked like when reef development shut down at the onset of the hiatus ~2,500 years ago. Credit: Lauren Toth

A new study has found that La Niña-like conditions in the Pacific Ocean off the coast of Panamá were closely associated with an abrupt shutdown in coral reef growth that lasted 2,500 years. The study suggests that future changes in climate similar to those in the study could cause coral reefs to collapse in the future.

The study found cooler sea temperatures, greater precipitation and stronger upwelling — all indicators of La Niña-like conditions at the study site in Panama — during a period when coral reef accretion stopped in this region around 4,100 years ago. For the study, researchers traveled to Panama to collect a reef core, and then used the corals within the core to reconstruct what the environment was like as far back as 6,750 years ago.

“Investigating the long-term history of reefs and their geochemistry is something that is difficult to do in many places, so this was a unique opportunity to look at the relationship between reef growth and environment,” said Kim Cobb, an associate professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. “This study shows that there appears to have been environmental triggers for this well-documented reef collapse in Panama.”

The study was sponsored by the Geological Society of America, the American Museum of Natural History and the Smithsonian Institution’s Marine Science Network. The study is scheduled for publication on February 23 in the journal Nature Climate Change. The study was a collaboration with the Florida Institute of Technology, with Cobb’s lab providing an expertise in fossil coral analysis.

Climate change is the leading cause of coral-reef degradation. The global coral reef landscape is now characterized by declining coral cover, reduced growth and calcification, and slowdowns in reef accretion. The new study provides data to assist scientists in understanding how changes in the environment trigger long-term changes in coral reef growth and ecosystem function, which is a critical challenge to coral-reef conservation.

“Temperature was a key cause of reef collapse and modern temperatures are now within several degrees of the maximum these reefs experienced over their 6,750 year history,” said Lauren Toth, the study’s lead author, who was a graduate student at Florida Tech during the study. “It’s possible that anthropogenic climate change may once again be pushing these reefs towards another regional collapse.”

For the study, the research team analyzed a 6,750-year-old coral core from Pacific Panamá. The team then reconstructed the coral’s past functions, such as growth and accretion (accumulation of layers of coral), and compared that to surrounding environmental conditions before, during and after the 2,500-year hiatus in vertical accretion.

“We saw evidence for a different climate regime during that time period,” Cobb said. “The geochemical signals were consistent with a period that is very cool and very wet, with very strong upwelling, which is more like a modern day La Niña event in this part of the Pacific.”

In Pacific Panamá, La Niña-like periods are characterized by a cold, wet climate with strong seasonal upwelling. Due to limited data at the site, the researchers cannot quantify the intensity of La Niña events during this time, but document that conditions similar to La Niña were present at this site during this time.

“These conditions would have been for quite an extended time, which suggests that the reef was quite sensitive to prolonged change in environmental conditions,” Cobb said. “So sensitive, in fact, that it stopped accreting over that period.”

Future climate change, similar to the changes during the hiatus in coral growth, could cause coral reefs to behave similarly, the study authors suggest, leading to another shutdown in reef development in the tropical eastern Pacific.

“We are in the midst of a major environmental change that will continue to stress corals over the coming decades, so the lesson from this study is that there are these systems such as coral reefs that are sensitive to environmental change and can go through this kind of wholesale collapse in response to these environmental changes,” Cobb said.

Future work will involve expanding the study to include additional locations throughout the tropical Pacific.

“A broad-scale perspective on long-term reef growth and environmental variability would allow us to better characterize the environmental thresholds leading to reef collapse and the conditions that facilitate survival,” Toth said. “A better understanding of the controls on reef development in the past will allow us to make better predictions about which reefs may be most vulnerable to climate change in the future.”


This research is supported by a Graduate Student Research Grant from the Geological Society of America, the American Museum of Natural History’s Lerner-Gray Fund for Marine Research, and grants from the Smithsonian Institution’s Marine Science Network. Any conclusions or opinions are those of the authors and do not necessarily represent the official views of the sponsoring agencies.


Lauren T. Toth, et al. “Climatic and biotic thresholds of coral-reef shutdown.” (Nature Climate Change, February 2015)

0 0 votes
Article Rating
Newest Most Voted
Inline Feedbacks
View all comments
February 23, 2015 11:04 am


February 23, 2015 11:09 am

Climate change is the leading cause of coral-reef degradation.
That’s nice…we’ve solved that runoff, sedimentation, pollution problem

Did they really just use a cold prove warm limiting?

Democratic Thinker
Reply to  Latitude
February 23, 2015 11:49 am

Sounds like it.

“The geochemical signals were consistent with a period that is very cool and very wet, with very strong upwelling, which is more like a modern day La Niña event in this part of the Pacific.”

“It’s possible that anthropogenic climate change may once again be pushing these reefs towards another regional collapse.”

But maybe they’re redefining Climate Change to be (AGC)&emdash;Anthropogenic Global Cooling—and abandoning (AGW).

Joel O’Bryan
Reply to  Democratic Thinker
February 23, 2015 3:52 pm

…its an evidence free assertion. A common tactic when the data shows you the opposite of your a priori expectation. The statement then becomes a declaration of faith needed to get past the Nature jounal AGW cognoscenti and the AGW reviewers in order to be accepted for publication.

Reply to  Latitude
February 23, 2015 5:06 pm

Yes. Most coastal coral reef problems have nothing to do with CAGW.

Janice Moore
Reply to  Rud Istvan
February 23, 2015 5:46 pm

Rud Istvan! (eye roll) How could ANYTHING have something to do with CAGW?
(btw: I got that gift card (yea!) and would have ordered your book 🙁 … but, it required that one own a Kindle and I didn’t want to use almost all my gift just to pay for one (don’t want one, except to read your e book).
Just wanted you to know I followed through on my promise (until it proved to be impractical for me — sorry).
So! I’ll make up for my not purchasing your fine book by advertising it here:,204,203,200_PIsitb-sticker-v3-big,TopRight,0,-55_SX278_SY278_PIkin4,BottomRight,1,22_AA300_SH20_OU01_.jpg
Best wishes for excellent sales!

Reply to  Rud Istvan
February 23, 2015 6:27 pm

Janice, thanks. But my ebook publisher does not require a Kindle device. Only the free Kindle SW reader on any platform. Also on iBooks for iPad, Kobo, B&N Nook… I use an old cheap iPad, and both the iBook and Kindle apps on it fixing typos and working toward a second edition.
Is hardware independent.

Janice Moore
Reply to  Rud Istvan
February 23, 2015 6:45 pm

Thanks for the technical advice, Rud Istvan. I was mistaken. I don’t have any of those other things either (I mistakenly thought I could just download it to my laptop as a .pdf). I much prefer paper books. If I get one of those devices, I will buy your book!

Reply to  Janice Moore
February 23, 2015 7:09 pm

Janice Moore (replying to Rud Istvan)

I don’t have any of those other things either (I mistakenly thought I could just download it to my laptop as a .pdf). I much prefer paper books. If I get one of those devices, I will buy your book!

I’ve got two Kindles – The older one is a grey-scale simple reader – good for stuffing a lot of novels into an airplane seat back or a hotel room. It’s got over 210 already loaded and read. The second, a Kindle Fire, is a color-display, touch-screen model That one is much, much better for scientific books because the color, high-density screen display graphs and charts better. But I’ve only loaded about 115 books on it. Haven’t had it as long.
lately, after buying a novel or sci fi book, I just download it to both versions as a default.
I thought there was a PC application that allowed you to “play” kindle books on the laptop.

Janice Moore
Reply to  Rud Istvan
February 23, 2015 7:21 pm

Hi, R. A.,
I wrote so sloppily! Yes, yes, I think I could have bought a sort of “app” to use the Kindle on my laptop — it still cost the bulk of my gift card, so… . 🙂
And I really much, MUCH, prefer paper books (unless it was an interactive-dependent one like maps that can be manipulated, etc…). One or two good ones is all I need to bring with me.
Thanks for trying to help me and HAPPY READING to you.

Reply to  Rud Istvan
February 23, 2015 7:48 pm

Janice, Calibre will read most documents and can be downloaded to PC.

February 23, 2015 11:17 am

“It’s possible that anthropogenic climate change may once again be pushing these reefs towards another regional collapse.” So last time it was natural climate variation but this time it’s man’s fault?

Reply to  markl
February 23, 2015 5:19 pm

No, no, no! Toth said “once again”; therefore, the last time there was a regional collapse it was also due to “anthropogenic climate change.”

Janice Moore
Reply to  Katherine
February 23, 2015 5:47 pm

LOL. She did! #(:))

February 23, 2015 11:17 am

It was as warm as today (graph featured on Gavin’s blog)

Gary Pearse
Reply to  vukcevic
February 23, 2015 2:21 pm

Gavin has this on his blog!!! Where was he when Marcotte was fileted by McIntyre for not realizing that even if the proxy was decent, it wasn’t in annual resolution. With 100% certainty, a record like this made up of century and more averaging would have had spikes removed. Gavin should average the entire instrumental record to get his data point!!

Reply to  vukcevic
February 24, 2015 5:25 am

If you think for 1 minute that .4 C covers 8000 years, you are not smart. What kind of filter is he using? 100 year smoothing?
.4 C barely covers year – to – year variation in the satellite era.

Mr. J
February 23, 2015 11:19 am

“It’s possible that anthropogenic climate change may once again be pushing these reefs towards another regional collapse.”
Once again a case of “having it both ways”. “Warm climate causes coral reef collapse” to “Cold climate causes coral reef collapse”.

Reply to  Mr. J
February 23, 2015 11:54 am

It is the funding collapse that is the one that they are really, really worried about.

Reply to  Mr. J
February 23, 2015 3:23 pm

I think it’s the rapid change in temperatures. See graph two comments above.

Janice Moore
Reply to  Mr. J
February 23, 2015 5:14 pm

Since “anthropogenic climate change” has never been proven to exist…
they might as well have said: “{Leprechauns} may once again be pushing … .”

February 23, 2015 11:21 am

All climate studies must reflect that it is bad and all of it is caused by man. Give me money. I don’t care what I’m doing to science to get money.

February 23, 2015 11:31 am

“Temperature was a key cause of reef collapse and modern temperatures are now within several degrees of the maximum these reefs experienced over their 6,750 year history,” said Lauren Toth, the study’s lead author,…”
“In Pacific Panamá, La Niña-like periods are characterized by a cold, wet climate with strong seasonal upwelling.”
So we are near max and that could cause collapse, but it was the cold that done them in last time and it is climate change what is doing it no matter what.

G. Karst
February 23, 2015 11:31 am

COLD and WET. We have NO crops that will grow during such, either. Other than for molds and fungi, very little can thrive, cold and wet. GK

Bill Murphy
Reply to  G. Karst
February 23, 2015 2:02 pm

Bummer. There goes my winter wheat crop. Better sell the combine.

G. Karst
Reply to  Bill Murphy
February 23, 2015 5:40 pm

Plowed under 100 acres winter wheat, last spring, after a hard winter. Replanted early corn. Worked out well. Combine still there. GK

Reply to  G. Karst
February 23, 2015 5:46 pm

How’s the still? Still out back, waiting for fuel and fodder (er, sugar) 8<)

Bill Murphy
Reply to  Bill Murphy
February 23, 2015 7:53 pm

Was being tongue-in-cheek. Sold off everything except 1/2 section of pasture with 15 acres of woods in it a few years ago. Combine is long gone too. (Not sayin’ nothin’ ’bout no still…) These days we play ranch on the pasture (20 head and a kid horse) and I use the woods as combo winter heat fuel and gym. Better workout and less boring than a treadmill and cheaper than propane. A few guys I know North of us had a similar prob with the wheat last year but locally most did OK. But we’re only at about 43° North.

February 23, 2015 11:37 am

Perhaps aliens driving big hummers were causing the C02 problems, back then. But since they’re gone, and the lefties cannot extort money out of them, we are expected to shoulder the blame for any problem that comes along, and therefore, we are being robbed, to allegedly, “save our planet”. It is such an absolute scam, it is hard to believe even the slowest of people couldn’t see through it.

February 23, 2015 11:37 am

Apparently toilet paper is worth more than graduate degrees from Georgia Tech.

Tom O
February 23, 2015 11:39 am

I will admit that the open mind these researchers have is a wonderful thing. Open to the idea of further research, that is, not to actually doing anything that might prove to be useful when interpreted the way they do, with the exception of paying off their college debts and “making a living,” something they are willing to deny millions of others from doing.

Ray Kuntz
February 23, 2015 11:40 am

“Warm climate causes coral reef collapse” vs. “Cold climate causes coral reef collapse”.
Which is it?

Reply to  Ray Kuntz
February 23, 2015 3:21 pm

Why can’t it be both?

Don K
Reply to  Ray Kuntz
February 23, 2015 8:24 pm

According to NOAA the corals found in tropical reefs prefer temperatures between 73F and 84F (23C-29C) and can tolerate temps as low as 64F(18C) or as high as 104F (40C) for brief periods.

February 23, 2015 11:47 am

“It’s possible that anthropogenic climate change may once again be pushing these reefs towards another regional collapse.”
They claim the collapse comes from colder ocean temperatures, La Nina predominant conditions. This spell lasted from ~2000BC to 500AD, to put dates on it. Sea level was rapidly increasing, looks like a meter a century for a few centuries 4K years ago:
So the oceans were rising 3-5X the current rate, but we have unprecidented, life-hobbling warming today. In contrast, modern CO2 obviously pales in light of this superior previous forcing, whatever it was.

Crispin in Waterloo
Reply to  skeohane
February 23, 2015 12:02 pm

Fairbridge was a strong opponent of CAGW, largely because of his own research into sea level variation.

Reply to  skeohane
February 23, 2015 1:34 pm

It is notable that excluding the dip in the curve, the period in question seems to have an estimate sea level between about 1 and 3 meters above present levels. I have never seen figures supporting that extreme, but over many parts of the globe there does seem to be support for a Holocene high stand about 1.5 meters above present levels.

Reply to  Duster
February 23, 2015 8:13 pm

From what I have read about archaeologic digs in the southern US, along the Gulf Coast, the shore line was 50 miles north of present, indicating a sea level 6 feet above today’s, 4000 years ago.

February 23, 2015 11:55 am

Jolly good show.
Did they see what happened between the years 995 and say 1400, or the Medieval Warm period, or a bit further back still to the Roman Warm Period? And – what happened in the 6,750-year-old coral core during The Little Ice Age (LIA)?
More Grant Money is obviously needed for any “Study” of this kind

February 23, 2015 11:55 am

What really kills coral: a falling sea level.
But a rising sea level fosters coral growth and a steady sea level stymies new growth.
No need to wring one’s hands over coral.

Reply to  mpainter
February 23, 2015 2:32 pm

since they put a ban on coral being used for building on pacific islands back in the early 1990s the coral has recovered and 80% of the islands are now stable or growing.

February 23, 2015 11:57 am

Michael Mann has said that global warming would lead to La Nina like conditions.

Alan Robertson
Reply to  MikeN
February 23, 2015 12:34 pm

Well allrighty, then. Michael Mann said it, that settles it.

Reply to  MikeN
February 23, 2015 4:12 pm

No. MM states over and over again we will see more frequent Super El Nino conditions and a general warming of the oceans. You know, that pesky hide and seek missing heat!

masInt branch 4 C3I in is
February 23, 2015 11:58 am

When the Anthropocene Jihadists at GISS, Guardian, Penn State U. and NYT get word of this they will try to get the graduate student thrown out on a Title IX presumptive-violation.

February 23, 2015 12:00 pm

I am waiting for them to discover that the most recent glacial period shut down the growth of the Great Barrier Reef when it suddenly found itself 100 meters above sea level baking in the sun.

Mike Maguire
February 23, 2015 12:07 pm

“Did they really just use a cold prove warm limiting?”
Yes, the bottom line is that we have humans that know what the perfect amount of CO2 in the atmosphere should be and what the perfect temperature should be at. Both those levels should be what they were before humans started burning fossil fuels.
This means that there is too much CO2 in the air right now and global temperatures are too warm. The objective is not to observe nature(and the widespread, positive response) but to assume that humans burning fossil fuels are changing CO2 levels much too fast and it is harmful.
All models and studies should start with this assumption because we should put our trust in those humans that tell us that they can save the planet if we just cut our CO2 pollution.
Not nearly as much mention of the other toxic stuff we spew into the air, water and soils or wasting of natural resources or bad environmental policies. That would just distract us from the objective of getting the real villain…….carbon dioxide.
These humans also know what the exact level and ph of the oceans should be, the exact amount of ice in polar regions should be and which pole(North) actually matters. They know what the population of every creature on the planet should be and how much rain/snow should fall as well as where droughts should be every year. They know that photosynthesis is an insignificant law, which carries no weight in this discussion.
They used to know things like how many tornadoes and hurricanes there should be but are waiting for a while before they let us know again about those weather elements.
They have made up for that in the last decade by letting us know where heavy snow and blizzards should and should not be. In fact, our country’s climate change czar, Dr. John Holdren, a leader of these enlightened humans, was nice enough to tell us last Winter about where extreme cold should and should not be and explained to us how CO2 is playing a role.
No question that these enlightened humans will continue to have much more to tell us about what sort of weather and climate we should and should not be having and what is causing it and most importantly, what we should do about it.
Please don’t check their data or the accuracy of their claims. This would be very insulting to these authorities/experts and considered anti science and interpreted as an attempt to sabotage their effort to enlighten us and save the planet.

Reply to  Mike Maguire
February 24, 2015 5:54 am

Sounds like a modern version of Noah and the arc. Build a ship, wait for the sea level to rise and decide who gets on and who doesn’t.

Reply to  Markopanama
February 28, 2015 9:32 am

that’s not far at all from the truth Marko. Give a read to all those environmentalists that unabashedly claim humanity is the problem! All the billionaires and “thinkers” that claim membership in the Club of Rome and promote the IPPC

February 23, 2015 12:12 pm

“several degrees”
Define “several”.
For me, “a few miles” would be between about 3 and 6 or 7.
“several miles” would be from about 8 to maybe 12 or 13.
(Note the hedging of bets here.)
Sloppy writing, or just scaremongering?

Janice Moore
Reply to  Oldseadog
February 23, 2015 5:07 pm

Careless and imprecise language is no accident.
It is a conscious attempt to confuse and deceive.

George Orwell

Mike Henderson
Reply to  Oldseadog
February 23, 2015 7:25 pm

“Sloppy writing, or just scaremongering?”

Mr. J
February 23, 2015 12:15 pm

I’d say sloppy writing, or both. Some of the wording in these “papers” is really confusing. Do they even know themselves what they’re saying? Makes me wonder.

Stephen Richards
February 23, 2015 12:22 pm

Are these people smoking colorado tabac

February 23, 2015 12:36 pm

Coral Reefs (1997) 16, Suppl.: S39—S46 (1997)
Biology and geology of eastern Pacific coral reefs
Abstract. The tropical eastern Pacific region has histori-
cally been characterized as devoid of coral reefs. The
physical conditions of the region are apparently not con-
ducive to reef growth: low temperatures, low salinity, and
high nutrient loads. But recent work has demonstrated
persistent coral growth in some locations at relatively
high accretion rates, dating at least 5600 y before present.
Coral reefs of the eastern Pacific are typically small (a few
hectares), with discontinuous distribution and low species
diversity. On a global scale, the eastern Pacific reefs may
be considered minimum examples of coral reefs, as they
have developed in possibly one of the most restrictive
environments in the history of coral reefs. Disturbances
are frequent, bioerosion intense, and recovery seems to be
extremely slow.
The tropical eastern Pacific extends from the Sea of Cor-
tez (Gulf of California) to the northern coast of Peru´

February 23, 2015 12:39 pm

They proved climate change kills coral. Climate Change is real, it’s happening now, and it’s caused by capitalism. So it is written, so it shall be.

Reply to  rh
February 23, 2015 7:38 pm

Right! Not. See several essays in ebook. Especially Shell Games.

DD More
February 23, 2015 12:42 pm

“We are in the midst of a major environmental change that will continue to stress corals over the coming decades, so the lesson from this study is that there are these systems such as coral reefs that are sensitive to environmental change and can go through this kind of wholesale collapse in response to these environmental changes,” Cobb said.
As I have stated before, the coral may be a little tougher and these worries over their stress levels are idiotic.
In the northern atolls of the Marshall Islands, 23 nuclear tests with a total yield of 76.3 megatons (TNT equivalent) were conducted across seven test sites located either on the reef, on the sea, in the air and underwater between 1946 and 1958. Five craters were created, the deepest being the Bravo crater at 73 m depth (Noshkin et al., 1997a) (Figs. 2, 3). Post-test descriptions of environmental impacts include: surface seawater temperatures raised by 55,000 C after air-borne tests; blast waves with speeds of up to 8 m/s; and shock and surface waves up to 30 m high with blast columns reaching the floor of the lagoon (approximately 70 m depth)
The results of our 12 year long nuclear war on coral. After less than 50 years, a total of 183 scleractinian coral species were recorded, compared to 126 species recorded in the pre-bomb study.
There are more species now than then.
And from
And in reporting the results of a study of a large brain coral that lived throughout the 17th century on the shallow seafloor off the island of Bermuda, Cohen and Madin (2007) say that although seawater temperatures at that time and location were about 1.5°C colder than it is there today, “the coral grew faster than the corals there now.”
Other studies have shown earth’s corals to be able to cope with climate-induced warmings as well as coolings. In a study of patch reefs of the Florida Keys, for example, Greenstein et al. (1998) found that Acropora cervicornis corals exhibited “long-term persistence” during both “Pleistocene and Holocene time,” the former of which periods exhibited climatic changes of large magnitude, some with significantly greater warmth than currently prevails on earth; and these climate changes had almost no effect on this long-term dominant of Caribbean coral reefs. Hence, there is good reason to not be too concerned about long-term changes in climate possibly harming earth’s corals. They apparently have the ability to handle whatever nature may throw at them in this regard.

An unofficial spokesman for the Allied Coral Species Association is thought to have stated – We have survived nuclear war, climate temperature changes of over 10 degrees, planetary magnetic shifts, giant undersea lava flows, 2,000-foot high super from Hawaii and plate tectonics for over 400 million years. We are personally more worried about you.

Reply to  DD More
February 23, 2015 1:18 pm

“There are more species now than then.”
Do they glow in the dark 🙂

Reply to  Jeff Patterson
February 23, 2015 1:46 pm

No, but they sometimes eat stray fishermen.

Janice Moore
Reply to  DD More
February 23, 2015 5:22 pm

Allied Coral Species Association {official statement}:
We have survived nuclear war, climate temperature changes of over 10 degrees, planet-scale magnetic shifts, giant undersea lava flows, … and plate tectonics…

DD More
That bore repeating with emphasis.

Reply to  DD More
February 23, 2015 6:02 pm

Well, using that information, steps to save the Great Barrier Reef are pretty clear. Nuke ’em! Eliminates the Crown of Thorn problem, disintegrates any mining cast offs and increases the bio-diversity of the coral themselves. What’s not to like! /sarc-off

Just an engineer
Reply to  Aussiebear
February 25, 2015 1:04 pm

Please wait until Rainbow Warrior is on location before you start saving the reef, you know to document the good that is being done. 😉

Bruce Cobb
February 23, 2015 12:45 pm

They like that word “collapse”. Maybe “climate collapse” will be the next transmogrification. Sounds so ominous.

February 23, 2015 12:49 pm

Richard Betts @richardabetts
‘Burst of warming may end lull in rising temperatures’
(via tallbloke’s)

Mike Maguire
Reply to  vukcevic
February 23, 2015 3:14 pm

‘Burst of warming may end lull in rising temperatures’
There is a chance of this happening and possibly right now. Here’s one of the important things to look for.
The Pacific ocean stores more heat than any ocean and has cycles, the most important one measured with the PDO index. When the PDO is negative, we have more cooling La Nina’s and I suspect heat probably gets stored in the Pacific. We saw global cooling from the 1950’s-70’s with a -PDO regime. This was around 30 years.
When it flips to positive, just the opposite happens. We have more El Nino’s, heat comes out and it causes a global warming influence. We had a +PDO from the late 70’s to late 90’s, culminating with the great El Nino of 1998, which is when the PDO flipped back to negative. This particular +PDO regime was shorter, only lasting a bit over 20 years.
From 1998 to the start of 2014, we have been in a -PDO regime, with more La Ninas, a natural global cooling influence. This offset the greenhouse gas warming effect from increasing CO2 in my opinion and could have been more responsible for the hiatus than any other factor.
That period above with the most recent -PDO was only 16 years. In the past, it appears as if many PDO regimes would last ~30 years, so this would be much shorter than that. If this did mark the end, there are several important things that may be going on.
We have had a positive PDO for over a year now, with the last 2 months having the highest readings yet:
If we have started the next +PDO regime, it means that natural global warming from heat coming out of the Pacific has commenced. If the last -PDO regime was in fact only 16 years, it could mean that the periodicity of the PDO index/cycle varies by much more than we thought(much shorter) or it could even mean that stored heat that used to take 30 years to come out, is doing so faster because of warmer oceans that have changed things a bit.
There is another possibility also. In the middle of the previous -PDO regime, during the late 1950’s, especially 1957/8, the PDO suddenly went positive. This was temporary as we backed down into negative territory, going the 1960’s, thru the mid 1970’s with a persistently -PDO.
Are we repeating the spike higher to a strongly +PDO here at around the halfway point of this -PDO regime in similar fashion to the previous -PDO or has the -PDO ended after only 16 years?
This is very important. While I believe that there is a continuous slight warming of the atmosphere from increasing CO2, the reason for the global cooling(50’s-70’s) accelerating global warming(80’s-90’s) then flat trend has a great deal to do with the sign of the PDO index.
It signals whether we will have more heat coming out of the Pacific or more heat going in on a decade(s) long time scale. This is more than speculation.
Looking at just the currently strong +PDO, one might lean strongly towards us entering the new +PDO regime. However, a couple of things make me suspicious. The atmospheric pattern, with the Ridiculously Resilient Ridge out west and Polar Vortex/cut off type lows in the East are more of a -PDO type pattern.
Also, a year ago, we had the makings of a what was supposed to be a massive El Nino for later in 2014.. Under a +PDO that should have happened. It’s a -PDO regime that tends to weaken El Nino’s like this one did. Maybe this is temporary excursion into +PDO territory like we witnessed in the late 1950’s.
Watch the PDO and signals coming from the Pacific ocean over the next 2 years. They should teach us a few things.

Mike Maguire
Reply to  Mike Maguire
February 23, 2015 3:29 pm

You can see the PDO index monthly values here:

Janice Moore
Reply to  Mike Maguire
February 23, 2015 5:39 pm

Great PDO essay, Mr. Maguire (a bona fide meteorologist)! Thanks for sharing.

Janice Moore
Reply to  Mike Maguire
February 23, 2015 6:12 pm

Your repeatedly asserted “belief” in the effect of human CO2 is deplorable, however… . Faith must work with REASON and evidence. Where there is ONLY speculation and conjecture (as with AGW), to “believe” is foolish.

Mike Maguire
Reply to  Mike Maguire
February 24, 2015 7:51 am

“Your repeatedly asserted “belief” in the effect of human CO2 is deplorable, however… . Faith must work with REASON and evidence. Where there is ONLY speculation and conjecture (as with AGW), to “believe” is foolish”
YW for the PDO stuff. On the belief that increasing CO2 from humans causes warming, we have loads of evidence from the known laws of physics as powerful evidence. To me, it’s not IF increasing CO2 has caused some warming but HOW MUCH.
We know that the planet has warmed up close to 1 degree C since the Industrial Revolution……….indisputable. CO2 levels have gone up from 280ppm to 400ppm.
Some items that prevent me from assuming that all the warming came from CO2 is the fact that we warmed naturally like this before during the Roman Warm Period and the Medieval Warm Period as well as many times in the past. We were already warming naturally, coming out of the Little Ice Age.
The fact that we can have stretches of natural cooling like the 1950′-70’s and lack of warming the last 2 decades shows that natural decades long cycles are very powerful and probably accounted for around half of the warming in the 80’s/90’s.
Also the effect of increasing CO2 is logarithmic……….the more and more you add, the less and less the effect.
Also, I observe negative feedbacks to the increase in CO2, warming and water vapor from increasing evapotranspiration, increase low clouds and decreasing cloud height.
Also, I will only mention the sun in the speculative category at this time but a more active sun in the last warming century and less active sun(sunspots) during the Little Ice Age is likely to be more than coincidence(I’m open minded to the Cosmic ray theory).
Could all the natural factors explain all the warming, with CO2 being responsible for none of it?
In order to believe this, you have to deny the laws of physics. I think sometimes, some of us focus to much on the “other sides” exaggeration and distorted interpretation(which is clearly happening) that we forget that there is an underlying fundamental principle that defines the basic assumption of their position.
CO2 is a greenhouse gas.
I think that most of the warming has been beneficial and know with absolute certainty that the increase in CO2 has been greatly beneficial to most life on this planet as seen by the booming biosphere and greening.

Reply to  Mike Maguire
February 24, 2015 7:57 am

Thanks for that. PDO suddenly reversed in 1963 from its natural cycle course, It took up a decade to recover;.look up ‘asteroidea’ experiment.

Janice Moore
Reply to  Mike Maguire
February 24, 2015 10:05 am

Mike Maguire: “we have loads of evidence from the known laws of physics ”
{Essex has a quote for you on that exact line at 48:00 on the below video, heh}
You need to investigate that claim further, with your fine research skills. So far… there is NO EVIDENCE AT ALL that CO2 drives climate shifts.
Chris Essex presents the actually state of the physics concisely and clearly here {WATCH THE ENTIRE VIDEO — I did and it is well worth it}:
Dr. Christopher Essex,
Chairman, Permanent Monitoring Panel on Climate, World Federation of Scientists, and Professor and Associate Chair, Department of Applied Mathematics, University of Western Ontario (Canada) in London, 12 February 2015
{video linked in above WUWT article and also here on youtube:}
7 Key “Impossible Things” Points (listed at ~ 1:07:06 in the video} in Video with approx. times:
{25:17} 1. Solving the closure problem. {i.e., the “basic physic” equations have not even been SOLVED yet, e.g., the flow of fluids equation “Navier-Stokes Equations” — we still can’t even figure out what the flow of water in a PIPE would be if there were any turbulence}
{30:20} 2. a. Computers with infinite representation. {gross overestimation and far, far, misplaced confidence in the ability of computers to do math accurately (esp. over many iterations) — in this section he discuss the 100 km square gaps {specifically mentioned at about 46:00} (i.e., cell size) — e.g., to analyze air movement, the cell would need to be, per Komogorov microscale, 1mm (aersols even smaller, microns)) — in climate data,
at about 44:00 His discusses the fact that even IF the basic equations were known, there isn’t enough time since time began to calculate even just a TEN – year forecast, even at super-fast speeds it would take approx. 10 to the 20th power years (the universe is only 10 to the 10th power years old)}
2. b. Computer water and cultural physics {also in Intro through ~14:50}.
{19:40} 3. Greenhouses that don’t work by the greenhouse effect.
{14:50} 4. Carbon-free sugar.
{15:40} 5. Oxygen-free carbon dioxide.
{passim} 6. Nonexistent long-term natural variability.
{49:00} 7. Nonempirical climate models that conserve what they are supposed to conserve {that is, they do not do this}.
Further, Dr. Murry Salby and others have good evidence from ice core proxies that strongly indicates that temperature drives CO2 emissions, not the other way around.
Dr. Salby, Hamburg lecture, April, 2013 (youtube)

Another video worth WATCHING IN ITS ENTIRETY.
And to end on a happy note:
Yes, we do agree on this: CO2 is good for plants (and, thus, humans)!
Best wishes to you in your continuing search for the facts!

February 23, 2015 1:08 pm

i’m still trying to wrap my head around a “wet” La Nina…
but i guess it has to rain somewhere, even when it’s not raining here in #Failifornia.

February 23, 2015 1:25 pm

Just a few years ago, a hard freeze hit Florida and resulted in lots of bleached coral.

Climate Atheist
February 23, 2015 1:33 pm

Like the State Department’s #2, Marie Harf, said about stopping terrorism with jobs, maybe there’s some nuance were not getting about cold and hot causing the same result.

Bill Murphy
Reply to  Climate Atheist
February 23, 2015 2:31 pm

She works for the State Department?????? Caught just part of that clip and thought it was somebody doing Lily Tomlin’s “Susie Sorority” skit. Silly me.

Janice Moore
Reply to  Bill Murphy
February 23, 2015 5:36 pm

Lily Tomlin “Suzie Sorority” (youtube)

How many seconds can YOU stand to listen… ?
Why did I post that? Because she has it coming. She is a disgrace.
The libs/AGWers put women up on stage to say their l1es and or inanities because people still think women are in general more trustworthy (eye roll).
It’s YET ANOTHER UNINTENDED CONSEQUENCE FAIL FOR THE libs, however. What the Envirostalinists/Enviroprofiteers/Libs gain for their message in pseudo-credibility will be COMPLETELY OFFSET by the annoyance factor: *CLICK!* channel changed.

Reply to  Bill Murphy
February 23, 2015 8:50 pm

Only trustworthy if the women prevent the male mental facilities from engaging and leave the guys just nodding.

February 23, 2015 1:57 pm

They describe the marine coral environment as “very wet”. I have snorkeled on reefs all along the central and eastern Caribbean and this is consistent with what I have observed. So I would tentatively say they might be correct on this one point.

Reply to  TonyL
February 23, 2015 4:47 pm

True. Corals don´t thrive in a dry environment.

February 23, 2015 2:17 pm

Reblogged this on Public Secrets and commented:
From the article: ““It’s possible that anthropogenic climate change may once again be pushing these reefs towards another regional collapse.”
So a coral reef shutdown four thousand, one hundred years ago is a warning of the dangers from the Demon CO2 today, even though a) there was no anthropogenically generated CO2 back then and b) this all seems tied to la nina/el nino cycles? Check. (Note the weasel words “possible” and “may.”)

Gary Pearse
February 23, 2015 2:38 pm

Egad, to do a study that shows cold kills the corals and then state that the continuing(?) warmiing will do the same with out any evidence is…is…surely even illegal isn’t it? Shameful. Maybe they just added this non sequitur in to divert us from sceptical analysis of their actual idea re cold killing coral. I guess they didn’t think back to how much colder it was 18,000yrs ago or how much wamer it was in the previous interglacial (Eemian). S’truth and zounds they took an interesting study and made it into a piece of crap with one paragraph.
Coral survived well during the glacial periods in which we spend most of our time! Interglacials are just a brief summer break. Do they mention how deep the water is over this reef? Maybe it drowned in a period of localized rapid sea level rise from faulting or got dusted up and poisoned by volcanoes?. An extraordinary theory needs extraordinary evidence and a look at all the factors is de rigueur. I would ask them if they investigated further away north and south…Where does this de-education of today’s students end?

February 23, 2015 2:54 pm

Coral growth was shut down for 2500 years, according to this study.
And then resumed.
Corals are capable of dealing with changing climates and changing pH. That is why they have survived over 100 million years. They may not survive in the exact same place, some will shift locations between ice ages and interglacials, just as fish will move north or south depending on whether you are in an ice ago or an interglacial (or in warmer or colder phases of either).

Andrew N
Reply to  John
February 23, 2015 3:21 pm

Agree, I’ll put my money on the evolutionary survivor.

Timo Soren
February 23, 2015 3:20 pm

I hope there is an in depth analysis of how coral can grow at different depths. Since, the oceans were rising at a rate approx. 10 meters over 4.5K BP to 3.5BP or 10mm a year. Hence, some of these corals, I suspect could have been pushed to too great of a depth to grow and hence just stagnated until other factors allowed for a resurgence.

February 23, 2015 3:40 pm

I believe that right around this same period of time is when we started to see a rapid drying out in the Levant and the level of the Dead Sea began to fall rapidly.

February 23, 2015 8:39 pm

Some corals live deep beneath the waves (in an an octopus’s garden in the shade). The most common example, Lophelia pertusa, has a mysterious affinity for hydrocarbons. That makes it a fair target for Greenpeace:
In recent years, environmental organizations such as Greenpeace have argued that exploration for oil on the north west continental shelf slopes of Europe should be curtailed due to the possibility that is it damaging to the Lophelia reefs – conversely, Lophelia has recently been observed growing on the legs of oil installations, specifically the Brent Spar rig which Greenpeace campaigned to remove.
Greenpeace’s campaign to remove the Brent Spar meant that in effect Greenpeace destroyed a rare species. [!]
This 70 year old coral reef began life as an oil tanker:

February 23, 2015 9:08 pm

“…We saw evidence for a different climate regime during that time period,” Cobb said. “The geochemical signals were consistent with a period that is very cool and very wet, with very strong upwelling, which is more like a modern day La Niña event in this part of the Pacific.”
In Pacific Panamá, La Niña-like periods are characterized by a cold, wet climate with strong seasonal upwelling. Due to limited data at the site, the researchers cannot quantify the intensity of La Niña events during this time, but document that conditions similar to La Niña were present at this site during this time…”

Ya gotta love the weasel words:
e.g. Those mystical geochemical signals that are consistent… Consistent? Is that new age climate speak for proven proxies?
Or that “…very cool and very wet…” periods. Wet? I thought salt water is wet? Were the somnolent corals dry?
Another example: “…with very strong upwelling…”; I suppose there is a proxy for that? Ocean litter and detritus in the coral layers? Are not corals just stationary filter feeders that feast on organic detritus?
“…In Pacific Panamá, … Due to limited data at the site,…”
Say, isn’t that another way of telling us the researchers love their vacation work site choice and want to go back frequently?
Reckon that we have to wait till the paper officially comes out with all details, data, methods and code.

February 23, 2015 9:18 pm

To summarise:
“4000 years ago cooling caused by upwelling devastated the Panamanian coral reefs. Therefore global warming could devastate the Panamanian coral reefs.”
Jack-ass science, a Dick- house publication.

February 23, 2015 10:05 pm

Recent PBS program, infrared light on coral shows they adapt to the bright hotter sun, acting as a sunscreen, they are not bleaching.
The bumphead parrotfish eat the coral and act as fertilizer with waste to feed more coral,
smaler fisg eat the alage from the coral.

February 24, 2015 9:18 am

“Cooler and wetter”

This is certainly a bizarre contortion, considering the reality of the climate in Panama and the Eastern Pacific, which we peer at on a daily basis. Obviously these “scientists” didn’t bother to learn anything about the weather in this area before they made their pronouncements.
The upwelling, at least near-shore, is driven by winds coming across the Panama Divide from the Caribbean during the “dry” season, from December to about April. Temperature is not a factor, wind speed is. More wind, more cool water upwelled from the deep. Any rain falls mostly on the Caribbean side of the mountains.
During the “wet” season, from May to November, the ITCZ shifts north a bit and the near-shore winds stop. Huge thunderstorms form in the Pacific and drift onshore into Panama. This is when the el Niño will come if it is going to.
Given that thunderstorms (the source of ALL the rain here) are creatures of heat, it’s hard to see how cooler will ever equal wetter. Unless they were talking about the ocean, in which case, wetter means???
Total blather.

February 25, 2015 12:01 pm

Odd that they didn’t point out the 4200 Kiloyear Event. A well known sudden cooling of the world.
Even the wiki knows about it (queue alarmist revisionists to get their erasers out…)

The 4.2 kiloyear BP aridification event was one of the most severe climatic events of the Holocene period in terms of impact on cultural upheaval. Starting in ≈2200 BC, it probably lasted the entire 22nd century BC. It is very likely to have caused the collapse of the Old Kingdom in Egypt as well as the Akkadian Empire in Mesopotamia. The drought may have also initiated southeastward habitat tracking within the Indus Valley Civilization.

Though I note that where it used to say it was a cold spike it now says “aridification” event… but it was cold, and it is dry when it is cold…
If you look on this graph from that link you will find a deep cold spike at about 4200 YA.comment image
It is cold that kills. BTW, that is ONE of the Bond Events that periodically happen. They are preceded by a warm spike. They happen roughly every 1470 years on average, and the last one was at the start of the Dark Ages in about 536 AD. Now lets see… 1470+536 = 2006…. One hopes this is one of the ‘closer to 1800 year’ odd cases and the snows in New England are not going to stay for a few hundred years…
Lost an Egyptian Empire, the Akkadian Empire, and a few other empires in that 4200 ybp / ya cycle.

Take just a moment to look back at the very long term solar status graph in paper from the prior posting.
Look for about 2200 B.C. to 2500 B.C. (The wiki has 2181–2055 B.C.)
The second period was from about 1200 B.C. to 1600 B.C. so take a look at that as well. (The wiki has 1650–1550 B.C.)
Notice the big “dip” in solar activity at about 1500 BC ( -1500 on the graph) and at 2500 B.C and 2200 BC ( -2500 and -2200 on the graph)? Those were strong solar slumps.

then quoting from one of the referenced papers:

It is the thesis of this study that the two Dark Ages, and the numerous disasters in the periods c. 2200-2000 and c. 1200-900 B.C., can be given coherence and can all be explained at once by a single primary cause. The cause I postulate as “historical reality” is drought-widespread, severe, and prolonged lasting for several decades and occurring more or less simultaneously over the entire eastern Mediterranean and adjacent lands. This is not to deny the significance of contemporary political and social factors; it is, however, to assert that a climatic economic deterioration of sufficient magnitude can set in motion forces beyond the strength of any society to withstand.

So it’s pretty well known that a very cold very dry event happened 4200 years ago (more or less) and had global disaster consequences. What I find of interest in this coral study is that talks to mechanism (shifts of ocean currents / patterns) and shows evidence for a global cold turn.
Watch for ‘extreme drought’ in Egypt to the Levant as this present sleepy sun cold turn continues to unfold. Oh, and as a bit of evidence that it is far colder now than in the past, this quote:

It goes on from there in very readable fashion. Particularly haunting are some of the actual texts from those eras that are being discussed. There are also various descriptions of the nature and degree of known changes in the climate and precipitation:

average difference between high and low water is 22′ (6.7 m.), with a yearly variation that depends on the volume of the equatorial rains; 4-5′ (1.21.5 m.) below average is a “bad Nile” and in antiquity a succession of these usually resulted in crop failures and famine, while a flood of 30′ (9 m.) or more would cause widespread destruction.Deposits south of Wadi HaIfa suggest that flood levels in early predynastic times were about 10 m. higher than today, that they declined in an oscillatory way to about 5 m. above today in early dynastic times, and to the present level by the time of the New Kingdom (Trigger 1965:31). It is hoped that the present study, in this and subsequent papers (now including Bell 1970), will provide additional details on the flood levels in historical times.

So talk about your ‘climate extremes’. They had stronger rainy periods in general by about 10 m at full flood. And then they had one heck of a drought. The implication seems to be that the next time a great drought comes, it will be even lower rains as our flood stage is already lower.

So rainfall, that drops off when things are cold and increases when things are hot, has been wobbling downward consistently for several thousand years. (Part of why we now find large Egyptian ruins of cities and more in dead sandy deserts today. They were thriving then…). So “now” we are a good 10 m lower at full flood. That’s a heck of a lot less water, and a heck of a lot more cold. Were we warmer we’d have more flood on the Nile, not less. And we are poised for a much deeper cold plunge this time as we continue the downward drift into the next Ice Age Glacial.

Verified by MonsterInsights