Jellyfish and Global Warming – another busted alarm

WUWT readers may recall seeing stories like these in the past. Warming wailers like Bill McKibben, who unthinkingly regurgitated this bogus Jellyfish news in op-eds like this one, take note.

A new new peer reviewed study shows that once again, these wild claims are falsely attributed to “global warming”. Instead, these temporary blooms are part of a natural cyclic global oscillation. Further, the researches find no trend saying

“…there is no robust evidence for a global increase in jellyfish.”

The stories, like the one above, are products of nothing more than increased awareness due to more eyes on the sea. We see the same sort of reporting bias effect in tornadoes, now that we have storm chasers and Doppler radar.

Here’s the Press release and PNAS paper: 

29 December 2012 University of Southampton

Jellyfish experts show increased blooms are a consequence of periodic global fluctuations

Blooms, or proliferations, of jellyfish can show a substantial, visible impact on coastal populations – clogged nets for fishermen, stinging waters for tourists, even choked cooling intake pipes for power plants – and recent media reports have created a perception that the world’s oceans are experiencing trending increases in jellyfish. Now, a new multinational collaborative study, involving the University of Southampton, suggests these trends may be overstated, finding that there is no robust evidence for a global increase in jellyfish over the past two centuries.

The results of the study, which includes lead co-author Dr Cathy Lucas, a marine biologist at the University of Southampton, appear in the latest issue of Proceedings of the National Academy of Science (PNAS manuscript # 2012-10920R).

The key finding of the study shows global jellyfish populations undergo concurrent fluctuations with successive decadal periods of rise and fall, including a rising phase in the 1990s and early 2000s that has contributed to the current perception of a global increase in jellyfish abundance. The previous period of high jellyfish numbers during the 1970s went unnoticed due to limited research on jellyfish at the time, less awareness of global-scale problems and a lower capacity for information sharing (e.g. no Internet).

While there has been no increase over the long-term, the authors detected a hint of a slight increase in jellyfish since 1970, although this trend was countered by the observation that there was no difference in the proportion of increasing vs. decreasing jellyfish populations over time.

Dr Cathy Lucas, who is based at the National Oceanography Centre, Southampton, says: “Sustained monitoring is now required over the next decade to shed light with statistical confidence whether the weak increasing linear trend in jellyfish populations after 1970 is an actual shift in the baseline or part of a larger oscillation.”

To date, media and scientific opinion for the current perception of a global increase in jellyfish was evidenced by a few local and regional case studies. Although there are areas where jellyfish have increased; the situation with the Giant Jellyfish in Japan and parts of the Mediterranean are classic examples, there are also areas where jellyfish numbers have remained stable, fluctuated over decadal periods, or actually decreased over time.

Increased speculation and discrepancies about current and future jellyfish blooms by the media and in climate and science reports formed the motivation for the study. “There are major consequences for getting the answer correct for tourism, fisheries and management decisions as they relate to climate change and changing ocean environments,” says Dr Lucas. “The important aspect about our work is that we have provided the long-term baseline backed with all data available to science, which will enable scientists to build on and eventually repeat these analyses in a decade or two from now to determine whether there has been a real increase in jellyfish.”

“The realisation that jellyfish synchronously rise and fall around the world should now lead researchers to search for the long-term natural and climate drivers of jellyfish populations, in addition to begin monitoring jellyfish in open ocean and Southern Hemisphere regions that are underrepresented in our analyses,” says lead author Dr Rob Condon, marine scientist at the Dauphin Island Sea Lab (DISL) in Alabama.

Given the potential damage posed by jellyfish blooms to fisheries, tourism and other human industries, the findings of the group foretell recurrent phases of rise and fall in jellyfish populations that society should be prepared to face.

From PNAS:

Recurrent jellyfish blooms are a consequence of global oscillations


A perceived recent increase in global jellyfish abundance has been portrayed as a symptom of degraded oceans. This perception is based primarily on a few case studies and anecdotal evidence, but a formal analysis of global temporal trends in jellyfish populations has been missing. Here, we analyze all available long-term datasets on changes in jellyfish abundance across multiple coastal stations, using linear and logistic mixed models and effect-size analysis to show that there is no robust evidence for a global increase in jellyfish.

Although there has been a small linear increase in jellyfish since the 1970s, this trend was unsubstantiated by effect-size analysis that showed no difference in the proportion of increasing vs. decreasing jellyfish populations over all time periods examined. Rather, the strongest nonrandom trend indicated jellyfish populations undergo larger, worldwide oscillations with an approximate 20-y periodicity, including a rising phase during the 1990s that contributed to the perception of a global increase in jellyfish abundance. Sustained monitoring is required over the next decade to elucidate with statistical confidence whether the weak increasing linear trend in jellyfish after 1970 is an actual shift in the baseline or part of an oscillation.

Irrespective of the nature of increase, given the potential damage posed by jellyfish blooms to fisheries, tourism, and other human industries, our findings foretell recurrent phases of rise and fall in jellyfish populations that society should be prepared to face.

h/t to WUWT “Bean”

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January 1, 2013 9:44 pm

You know, I just figured out my wish for 2013, I just want all the hysteria to go away and reason to return!

January 1, 2013 10:21 pm

Like every other “It’s worse than we thought” story, the idea was to get the panic into the hearts of the people (I know, I know, no one taught them about overkill). Once in the press, it didn’t matter if it proved to be false – people remember the story, not the quiet “Oh, no it isn’t,” softly brought up months or years afterwards.
Now the extremes just make me laugh out loud and I’m sure I’m not the only one. By the way, has that list of all the things global warming “causes” been updated recently? I pretty well fell out of my chair when I first saw it. I was talking on the phone to my sister at the time. I clicked on the link with the idea of reading it out to her. Ha! When the page opened, I exclaimed down the phone line, “Oh my God, there is no way I can read all this out!” Then I gave her the link so she could check it out herself.
That list was pretty big then, it must be huge now. 🙂

January 1, 2013 10:27 pm

If anything on this planet is increasing or decreasing – it’s automatically due to CAGW – because it correlates – either positively or negatively. That’s why the operative adjective of the ecofreaks is “sustainability” – a trend line of slope zero!

January 1, 2013 10:41 pm

If this jellyfish is the species I think it is their repoductive process, somehow and I forget the actual term to decribe it, is “enhanced” by the way the Japanese fishermen deal with the full grown animals in fishing areas. They simply shred the full grown animal which, somehow, can still reproduce leading to an increase in populations but smaller in physical size. I watched a documentary about it years ago, and the cause of the increase in full grown animals? You got it, AGW! It was really interesting until that point.

January 1, 2013 11:52 pm

Jellyfish swarm northward due to global warming – sheesh!
Back when global cooling was the bogeyman, it was said that armadillos were fleeing south to escape the encroaching cold. (Christian Science Monitor 27 August 1974)
Some enterprising soul should crossbreed them. Jellydillos!

January 1, 2013 11:57 pm

The difference between these stories and fairy-tales is that fairy-tales are entertaining and interesting.

January 2, 2013 12:03 am

Oh Noes. My favorite dessert is growing? Oh wait. Jelly,not Jello,darn.

January 2, 2013 12:10 am

And in futher news, my blue spruce grew by 2″ this year! Arrrgghhh.

george e smith
January 2, 2013 12:11 am

I’m sure jellyfish are capable of going anywhere that meandering ocean currents want to takr them.
Ho hum !

January 2, 2013 12:14 am

Over-fishing of teleost fish is a potential cause of increased jelly-fish populations, at least locally.

January 2, 2013 1:06 am

I remember how in the 1970s (when I was a child) we couldn’t swim in the Black Sea waters because of the jellyfish population explosion. The sea has become, literally, a jellyfish soup; those jellyfish had a relatively mild sting but constantly bumping into them resulted in serious skin irritation (not to mention the dubious joy of swimming in slime). This “blooming” continued at least for two weeks — not a negligible matter, considering that the opportunity to have a vacation on Black Sea was rare, that vacation time was short, and that we had virtually no money.
(Calling yourself “dirt poor” while having your own cattle farm is a purely Californian concept, hardly understood in other parts of the world.)
Supposedly, 1970s were the coolest time in recent decades?

January 2, 2013 1:07 am

“Sustained monitoring is now required over the next decade to shed light with statistical confidence whether the weak increasing linear trend in jellyfish populations after 1970 is an actual shift in the baseline or part of a larger oscillation.”
or, as you admit it is a weak trend, you could save the money and do something productive. typical example of people thinking their own subject area is overwhelmingly important. how much money will it cost to see if this weak trend in jellyfish is statistically sound or not? who really cares? why not count penguins or krill? why not only count things that suggest a strong trend?
‘domestic cat numbers have been steady over the past 40 years but we need to spend vast amounts increasing confidence in this “trend”‘

Geoff Sherrington
January 2, 2013 1:19 am

Al Gore wrote in “Earth in the Balance” that increased UV light was bliding salmon fish and rabbits in Patagonia.
The hardest part to swallow was the near absence of any monitoring stations on Earth measuring incoming UV light.
At least we still have salmon& rabbits that can see; and jellyfish; plus some more UV monitors; but now it’s Al who is in danger of growing blind from what parents used to warn males about at adolescence.

January 2, 2013 1:24 am

Seems the box jellyfish is slow coming north this season. Bet that’ll be blamed on AGW.

January 2, 2013 1:41 am

Jellyfish, wonderful positive displacement pumps that they are, according to the research reported here, mix shallow and deeper ocean waters as much as tides and winds.
see –
Wow, more jellyfish – more ocean mixing.
For the authors of the research, this raises several questions about ocean currents. And for me it raises questions about heat-sinks too and enhances my thoughts on the robustness of climate feed-backs being strong in maintaining a good level of equilibrium – otherwise we wouldn’t be here now.

January 2, 2013 1:45 am

Science by press realise not fact has long been a standard approach within Climate Science, it merely shows these people know that their not engaged in scientific argument but one camps-out in politics.

Chris Schoneveld
January 2, 2013 1:53 am

Some years ago I had this letter published in The Australian.
“ROSS Garnaut’s climate change review is flawed from the outset (“PM told to get real on carbon cuts”, 22/2). It accepts the premise that climate change is inherently bad. It uncritically follows the Intergovernmental Panel on Climate Change’s stance without an independent review on the validity of the premise.
It is a demonstrably invalid premise. One only has to take randomly about 50 things humans like (butterflies, cave paintings, wine, peace, health) and 50 things we don’t like (sharks, feral cats, jellyfish, allergy, crime, drought, floods) and perform a Google search for each in combination with the term global warming or climate change and the following will emerge: anything we like will be negatively affected and anything we don’t like will benefit from global warming. For example, you will never find butterflies thriving or cockroaches suffering.
Since the forces of nature are insensitive to the preferences of humans, one would expect a balanced outcome of thriving or declining likes and dislikes. Since this is not the case, the statistical significance of this exercise allows us to draw the conclusion that the science of climate change is alarmist and subject to severe bias.”

January 2, 2013 1:54 am

It’s funny how most jellyfish scare stories tend to focus on increases in jellyfish. You hear very few stories in the media, if ever, about their decline.

Hydrobiologia May 2001
Jellyfish blooms: are populations increasing globally in response to changing ocean conditions?
…….The issue is not simple and in most cases there are few data to support our perceptions. Some blooms appear to be long-term increases in native jellyfish populations. A different phenomenon is demonstrated by jellyfish whose populations regularly fluctuate, apparently with climate, causing periodic blooms. Perhaps the most damaging type of jellyfish increase in recent decades has been caused by populations of new, nonindigenous species gradually building-up to `bloom’ levels in some regions. Lest one conclude that the next millennium will feature only increases in jellyfish numbers worldwide, examples are also given in which populations are decreasing in heavily impacted coastal areas………..

Ben D
January 2, 2013 2:46 am

“…there is no robust evidence for a global increase in jellyfish.”
Thing is,.. will this item get the msm coverage to correct the error of their earlier fear mongering?
Of course not, the Pied Piper rulers of planet Earth want nothing less than keeping the masses in fear of that which only they know how to save them from,…but it will require a carbon tax income to fund it!

Bloke down the pub
January 2, 2013 2:49 am

Does the hat/tip go to a jelly bean?

January 2, 2013 4:32 am

Back in the past it seemed that local (NC coast) jellyfish numbers and locations were more affected by currents, tides and winds. Some days they were too plentiful and some days you didn’t see any. I suppose the affects of these factors no longer apply now that we have discovered AGW.

January 2, 2013 6:02 am

Reblogged this on Public Secrets and commented:
And another canon of faith in the Church of Anthropogenic Global Warming goes bust.

January 2, 2013 6:59 am

I would think that the Japanese and perhaps the Chinese have written records back centuries. Much has been learned about Tsunami by scouring the, often detailed, records. It would seem odd to me that records about fish catches, (plentiful, lack of, types, seasons, dates caught), would also be kept including records about Jellyfish. It is entirely possible that Britain, Dutch (generalization) and Spain, as masters of seagoing enterprises during colonial days would also have records.
Any reason researchers did not first look for written accounts? Or was Wiki (wicked) ressearch too easy to pass up and still get a potful of money, ocean and beach time…?
As a long time coastal fisherman, summer blooms of jellyfish were intermittent and usually more a factor of currents, tides and wind. There was often a hurriedness amongst the shore casters when the wind and tide would shift as we knew easy casting would end soon. Determined fishers would keep cast though every cast would snag seaweed and jellys (though only the biggest toughest jellys could be dragged to shore, especially if there was sufficient seaweed to buffer our attempts to yank the lure free).
The jellyfish scare started years before I found WUWT. And was one of the media disaster scenarios along with drought, famines, melting glaciers, shark eats man, man eats shark fin and Manniacal’s uncombed hair that caused to me to start looking for direct observational science; not models. A geologist friend pointed me to WUWT and real science.
A fish/ocean biologist once opined to me that he thought total ocean biomass stayed roughly consistent from year to year. Depletion of one part of the biomass resource allows another part of the biomass to increase. Fluctuations are normal and in many cases, the actual cause of fluctuations are still unknown.
Feast and famine are just as much of the ocean cycle as the land going cycle. Prey increases and soon after, predators increase; when prey suddenly declines there are a lot of very hungry and conceivably desperate critters roaming around looking for a mouthful. Predator decline is inevitable when their natural prey is not available.
Striped bass and other predator fish are noticeably thinner during certain seasons in the Chesapeake Bay; usually after their preferred forage (ale’wife, aka Alosa pseudoharengus) is vacuumed from the bay and turned into commercial products. Products like cat food, oil, vitamin E… and so on. The ale’wife is a filter feeder and their mass removal from the bay is a major impact on bay water quality. Is this science settled? Not by any standard, especially given the huge $$ reaped from ale’wife and everyone concerned about bay fishing and bay water. Except, perhaps, for the poor shore fisher who spends twenty bucks on tackle and bait hoping to score some good dinner food, (striped bass, flounder, weakfish, bluefish, etc…), and has almost no say about utilization of the ale’wife resource. (hint; poor poor me, sniff sniffle…) Just a little whining for my own sense of proportion, but a situation indicative of Archaebacteria, Eubacteria, Protista, Fungi, Plantae or Animalia population impacts worldwide; whether or not mankind interferes or even exists. One gains, another loses; sometimes in concert, sometimes in opposition…
Of course, when one fishes, but hasn’t had a bite yet during a long day fishing and one is fishing alongside of an equally fishless biologist friend; what is stated is opinion, not actual observed definitive facts. It was a good gripe and insight by the biologist, but it didn’t help my fishless day much. Still, as the old saying states; “A bad day of fishing is better than a good day at work”; and I’m always feeling better with a line in the water.
His opinion that day was one that has stuck with me over the years and has caused me to cast a wider eye, esecially as concerned to the fish quarry I am pursuing that day. His frank opinion still strikes me as better advice than that produced by any of the d____ed climate models and all their disaster assumptions based on catastrophic thinking using those models… When one wants to find catastrophes in the modeled data, (thus guaranteeing next years $$ grant) it is all too easy to find death and destruction around every corner… DOOOOMMMM!
Yeah, right! Go get a real job thou climate egg sucking, data adjusting, grant and MSM monopolizing, catastrophic doomsayer miscreants! In my ever so humble opinionated thinking… Buy extra Josh/WUWT calendars and post them where politicians and climate doomsayers wil see them… Preferably out of their reach.

January 2, 2013 7:00 am

The transportation and introduction of non-native jellyfish species in ships ballast water is much more likely a cause for regional jellyfish blooms that global warming.
90% of the animal biomass in the oceans is jellyfish. 90% of the animal biomass on land is worms. Neither species is likely to experience anything more than a regional population explosion due to the limits on global food supply. Jellyfish eating jellyfish, worms eating worms is not going to increases total biomass.
While global warming has led to an alarming, 7 fold increase in human biomass over the past 150 years, humans play only a minor part in the total animal biomass. So long as worms and jellyfish play only a minor role in human diet this is likely to continue.

January 2, 2013 7:14 am

Ben D says:
January 2, 2013 at 2:46 am
Of course not, the Pied Piper rulers of planet Earth want nothing less than keeping the masses in fear of that which only they know how to save them from,…but it will require a carbon tax income to fund it!
We got rids of the Kings and Queens of old because their universal solution was human sacrifice in the form of toil, taxes and lives. Their replacements see themselves as Kings and Queens to rule over us, using the same prescription.
The notion that experts are any better at predicting the future than anyone else has led to the fall of many great empires. No nation can long survive the luxury of spending its wealth on folly.
Our economies were not built by lawyers. Yet we elect them in increasing numbers to high office, trusting that adding more and more laws will somehow make us free.

January 2, 2013 7:29 am

It seems like McKibben, and others of the CAGW ilk, apply the following theorem when interpreting current events: If something dreadful is happening it must certainly be due to “climate change”
Corollary: Nothing good can ever proceed from “climate change”

David L
January 2, 2013 8:38 am

This is basic biology101. I can’t believe climate “scientists” never hear of the “fox and hare cycle” known for years. When hare populations are low it drives the fox population down due to lack of fox food. When the fox population declines it allows the hares to proliferate due to lack of predators. But then the increase of fox food brings the fox populations back to record numbers. As a climenut scientist, no matter when you start measuring the fox or hare populations one will be growing and the other declining at “record and unprecedented rates obviously due to climate change.”. Neat how that works?

January 2, 2013 12:22 pm

ferd berple says:
January 2, 2013 at 7:00 am
“….While global warming has led to an alarming, 7 fold increase in human biomass over the past 150 years, …”
Why is this alarming?

January 2, 2013 2:08 pm

RE: Chris Schoneveld says:
January 2, 2013 at 1:53 am
Excellent point. Made me chuckle, as well.

David L
January 2, 2013 2:40 pm

RE: Chris Schoneveld says:
January 2, 2013 at 1:53 am
“Bingo” as they say!

Robert kral
January 2, 2013 6:07 pm

Jellyfish are a prey species for many animals, including fish and turtles. If you can’t show that the predator population has not changed, you have no business invoking other causes for a change in prey populations. Kill the coyotes, and the jackrabbit population explodes. It’s one of the best documented relationships in ecological science. Sheesh.

January 3, 2013 1:15 pm

so not robust evidence ?

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