Guest essay by Eric Worrall
Sharks survived the dinosaur killer, the Cretaceous-Paleogene extinction event which wiped out 80% of Earth’s species, but apparently our gentle 0.1C / decade global warming is a grave threat to their continued survival.
How will sharks respond to climate change? It might depend on where they grew up
November 27, 2020 6.01am AEDT
Culum Brown Professor, Macquarie University
Connor Gervais Connor GervaisThey may have been around for hundreds of millions of years — long before trees — but today sharks and rays are are among the most threatened animals in the world, largely because of overfishing and habitat loss.
Climate change adds another overarching stressor to the mix. So how will sharks cope as the ocean heats up?
…
An existential threat
In Australia, the grim reality of climate change is already upon us: we’re seeing intense marine heat waves and coral bleaching events, the disappearance of entire kelp forests, mangrove forest dieback and the continent-wide shifting of marine life.
The southeast of Australia is a global change hotspot, with water temperatures rising at three to four times the global average. In addition to rising water temperatures, oceans are becoming more acidic and the amount of oxygen is declining.
Any one of these factors is cause for concern, but all three may also be acting together.
One may argue sharks have been around for millions of years and survived multiple climate catastrophes, including several global mass extinctions events.
To that, we say life in the anthropocene is characterised by changes in temperature and levels of carbon dioxide on a scale not seen for more than three million years.
…
Read more: https://theconversation.com/how-will-sharks-respond-to-climate-change-it-might-depend-on-where-they-grew-up-150460
The study is available here.
I think most Australians if asked would suggest there are too many sharks.
I swim in Australia’s coastal waters a lot less than I used to, and never venture out too deep. The beloved politicians who run our country have cut back on shark culling near popular beaches, because you know, if you venture into their territory you should accept a little risk. Something to think about when our borders re-open, if you are thinking of visiting Australia for a New Year beach holiday.
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That sounds like an argument for global warming.
Along with a propensity for Fewer Sharknados
I guess SyFy channel will be affected by Climate Change
Any reduction in the number of sharks comes as good news. Recently, Australian politicians have begun to cut back on shark netting and culling near popular beaches, in a futile attempt to mollify the Greens and possibly also to reduce rising Australian population numbers impinging on the Australian Budget.
Reducing population number’s ? Just appoint the premier of Victoria for four more years!
Shark attacks are increasing because there are many more people now, and they go swimming in the oceans.
Plus, with warming seas, this prolific human shark-bait is now parboiled, making them much more tender and appetizing to the after-darks.
Someone more mathematically gifted than me will present the numbers that prove this correlation.
Sharks will die out from over-eating human meat. Meat is bad for you, as Greta told us.
I gave up eating human meat decades ago
– Hannibal Lecter.
Deep Statebook Zuckers wife sisters restaurant name?
I have been to the library at Macquarie University, Sydney, NSW where the first author claims to reside. Thought it was better than that, but that has been some years. Paper too expensive, but tables available. Last line of abstract “With climate change, intraspecific variation will manifest as populations move, demographics change or extirpations occur, starting with the most sensitive populations.” Also “However, under Adelaide temperatures, the MO2Rest of Jervis Bay sharks was greater than that of Adelaide sharks.” Might the nice people I met at Jervis Bay not take issue about “more sensitive” Adelaide sharks 1200 km away?
Table S1: Top GLMM/LMM model selections.
Statistical summaries for GLMM/LMMmodels…, and so on” I’ll leave the numbers to the stat guys, but didn’t look that bad, maybe made up anyway, would have to get the data from the authors.
Great whites are cold temperate sharks, suspect that it could be found in their library, overheating might cut down on the attacks. Anyway, Sydney had a great (among other) seafood market. Didn’t see any great whites.
Not about to go extinct, but maybe need to control killer whales better.
When one variety of a species decreases, usually another, better adapted species increased to fill the other’s niche. Noticed the increase in lawyers?
I emmigrated to Australia 40 years ago. I clearly remember for many years one never heard of a shark attack. These days they are a regular weekly if not daly occurrence. Culling large sharks seems to me to be a reasonable solution. Go ahead do it.
“I clearly remember for many years one never heard of a shark attack. These days they are a regular weekly if not daily occurrence.” I hope you realize you just gave alarmists yet another reason (probably already used anyway) to claim proof of global warming. 🙂 Careful, these people are controlling nuts with way too much time on their hands.
There seems to be a bit of ill-feeling towards sharks here. I don’t have a problem with them myself, although if I ever did I would just get a bigger boat.
Gotta blame it on Climate Change because, they can’t tell the truth. The biggest threat to sharks are the Chinese; they’ll eat anything and, with 1.5 billion mouths to feed, they’ll eat everything. Shark fin soup is disgusting but, it’s what kills a lot of sharks these days.
The study is paywalled for me. But the Supplementary Materials make it look like the study was based on models. 6 pages.
————————————-
Electronic Supplementary Materials
Population variation in the thermal response to climate change reveals differing sensitivity in a benthic shark
Top GLMM/LMM model selections. The top-ranked models are in bold and were determined via the lowest AICc score (Akaike’s information criterion corrected for small sample size). k is the number of model parameters, ΔAICc is the difference between the current model and the top-ranked model, wAICc is the model probability, and Rm is variance explained by the fixed effects (marginal variance).
https://onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1111%2Fgcb.15422&file=gcb15422-sup-0001-Supinfo.pdf
You actually missed the funnier part of the stupidity of that study … which is actually batsh$t crazy these tossers deny Evolution. The concern they have is “intraspecific variation will manifest” as defined by these over educated dropkicks from the university of autism.
So remember the basic law of Evolution that all species will evolve you must throw that out the window and replace it with the theory that there is an ideal optimum nature period apparent somewhere in the 1900’s. All nature must remain exactly as it was during this ideal period. You must deny Evolution and all variation is bad.
The study data simply says some shark species move more depending on water temperature. If the water temp changes then you will get a changed rate of intraspecific variation. That isn’t good or bad it’s just a fact and the study doesn’t even deal with other factors or how significant it might be. The effect could be very minor and of no interest at all.
The study itself isn’t the problem it is what crackpot Prof Culum Brown says that is the issue and example of another activist who can’t deal with the conflict between activism and science.
My goldfish manage to survive in a bowl where the temperature changes by >10 degrees between summer and winter… but apparently 1 degree/decade will send sharks extinct. How desperate are the alarmists sounding?
“oceans are becoming more acidic ”
ROFLMAo.
As soon as you see a moronic anti-science statement like that…
.. you KNOW the rest is just AGW mantra BS !!
Coral bleaching occurs during El Nino cycles because the sea level over the coral DROPS, exposing the coral to too much sunlight.
Mangrove die back in 2015 also due to LOW sea levels
“Diebacks in Mangrove Bay were coincident with periods of very low sea level, which were associated with increased soil salinization of 20–30% above pre-event levels”
https://www.nature.com/articles/s41598-017-01927-6
“Mangrove die back” (Fred250) may also be caused by changes in coastal topography. Mangroves have a significant role stabilising coastlines, which is why it is an offence where I am to cut down mangroves. Sometimes the off-shore sand bars move faster than the mangroves can catch up with. Happened with one patch near the shoreline at QNI, and the (then) owners spent money clearing a flow path, so the company would not be accused of causing the problem by failing to manage sediment run-off or something.
Sharks have lived through more climate changes than most species.
Slapping a “climate change threatens the (studied species)” sticker on your latest study for a biologist or ecologist is just programmed behavior in the academic world where getting tneure means first getting grants. So these guys who study sharks and counting numbers are jumping onboard the climate gravy train to grant success, so they can do what they really want to do… count sharks and study their behaviors. The financial rewards (grant success) have been put in place to reward those who jump on the climate scam grant train, and punish those who refuse.
We see this programmed human behavior of course clearly in polar bears. The PB is the “poster child” for Arctic climate change and how Susan Crockford calls out certain researchers regularly for hyping and claiming impending PB demise even as their numbers steadily increase.
The IPCC knows this. The CMIP folks know this. They need to make climate addicts out of as much of the academic research community as possible. Get them on that gravy train, because then they have loyal followers, like drug dealers have drug addicts. Grant money is the drug.
So the IPCC and the GCM CMIP community decided 20 years ago to put together unrealistic emissions-forcing scenarios, dishonestly call them business-as-usual (BAU), in order for non-climate researchers to grab that “worst case” scenario outputs and claim impending doom for whatever diverse area of study that alarmist warming touches.
The attacks in 1916 that inspired “Jaws” were viewed with skepticism. Many – including prominent scientists – believed sharks would not attack humans, let alone be capable of killing humans.
https://www.floridamuseum.ufl.edu/science/how-a-century-of-fear-turned-deadly-for-sharks/
Sharks have been around a hundred million years. Will sharks survive climatic conditions last seen 3 million years ago? Both dates from the article. Um, they’ve survived them once, why not again?
Except its currently cooler now than for most of the last 10,000 years.
Ocean heat content has only recovered slight from the LIA.
And none of that recovery has any human causation.
Yes, it’s not like sharks are mobile and could move to colder water south or north or something.
Klimate change jumps the shark…again.
Snorkeling on the Great Barrier Reef offshore Cairns in early 2005, I came face-to-face with a ~5 foot reef shark – it looked me right in the face from about 3 feet away, and concluded: Nah! Too old and too tough – not worth the trouble – and swam away. My only close encounter of that type.
The blue-bottle jellyfish were another story – got stung across my neck and foot, burns like fire but I got off easy. One of our team took a break, holding on the swim grate, and took out his mouthpiece. A blue-bottle wrapped around it and he put it back in his mouth! Poor guy had gigantic swollen Mick-Jagger-Lips for the rest of the week. Some people say uric acid helps to dull the pain – I say alcohol, lots of it, is better.
… a really jaw-dropping piece of research.
The great white has apparently disappeared from the waters near Cape Town. Because orcas have put them on the menu.
“The beloved politicians who run our country have cut back on shark culling near popular beaches,…”
More deaths from sark attacks.
“The beloved politicians who run our country have cut back on forest fuel load management,…”
More wild bush fires.
I see a trend here…
More recently, about three million years ago it was considerably warmer than today with very similar levels of CO2 and sharks survived. More recent than that, the previous interglacial period, the Eemian, was warmer than this one with higher sea levels and more ice cap melting yet sharks survived. Concerning the survival of sharks, the climate change that we have been experiencing cannot possible be a concern.
I’m sure sharks will survive the Cretinaceous period, too.
Although, the Stupid might burn them.
If a shark eats a warmist, does he get MSD (mad shark disease)?
I thought everything was threatened by “climate change™”.
According to University of Queensland and Griffith University researchers : “The key thing that our study shows is that large apex sharks on the Queensland coastline have been declining over the last 50 years,”
https://www.uq.edu.au/news/article/2018/12/fifty-years-of-decline-queensland’s-coastal-sharks
Looks like sharks have other problems more pressing than a timid water temperature change.
The research team said factors such as climate change, which is affecting shark populations, could not explain the scale of the decline.
“We can be fairly certain the cause of the decline is fisheries related. There’s not very many other things it can be,” Dr Roff said.