Guest essay by Eric Worrall
Scientists claim that a 5C warming will kill off 60% of the world’s fish. But such claims ignore major abrupt temperature excursions which occurred in the not too distant past.
Climate change will make world too hot for 60 per cent of fish species
ENVIRONMENT 2 July 2020
By Adam Vaughan
Fish are at a far greater risk from climate change than previously thought, as researchers have shown that embryos and spawning adults are more susceptible to warming oceans.
In a worst-case scenario of 5°C of global warming, up to 60 per cent of fish species around the world would be unable to cope with temperatures in their geographical range by 2100, when different stages of their lives are taken into consideration. Even if humanity meets the Paris deal’s tough goal of holding warming to 1.5°C, it would be too hot for 10 per cent of fish.
Previously, we thought that just 5 per cent of fish species would struggle to cope with 5°C of global warming, but that was based on analysis of adult fish alone.
“We can say 1.5°C is not paradise, there will be changes. But we can limit those changes if we manage to stop climate change. Fish are so important for human nutrition, so this study makes a strong case for protecting our ecosystems and natural environments,” says Hans-Otto Pörtner at the Alfred Wegener Institute in Bremerhaven, Germany, part of the team behind the research.
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Read more: https://www.newscientist.com/article/2247602-climate-change-will-make-world-too-hot-for-60-per-cent-of-fish-species/#ixzz6REJS463Z
The abstract of the study;
Thermal bottlenecks in the life cycle define climate vulnerability of fish
Flemming T. Dahlke1,*, Sylke Wohlrab1,2, Martin Butzin1, Hans-Otto Pörtner1,3,*
See all authors and affiliationsScience 03 Jul 2020:
Vol. 369, Issue 6499, pp. 65-70
DOI: 10.1126/science.aaz3658Species’ vulnerability to climate change depends on the most temperature-sensitive life stages, but for major animal groups such as fish, life cycle bottlenecks are often not clearly defined. We used observational, experimental, and phylogenetic data to assess stage-specific thermal tolerance metrics for 694 marine and freshwater fish species from all climate zones. Our analysis shows that spawning adults and embryos consistently have narrower tolerance ranges than larvae and nonreproductive adults and are most vulnerable to climate warming. The sequence of stage-specific thermal tolerance corresponds with the oxygen-limitation hypothesis, suggesting a mechanistic link between ontogenetic changes in cardiorespiratory (aerobic) capacity and tolerance to temperature extremes. A logarithmic inverse correlation between the temperature dependence of physiological rates (development and oxygen consumption) and thermal tolerance range is proposed to reflect a fundamental, energetic trade-off in thermal adaptation. Scenario-based climate projections considering the most critical life stages (spawners and embryos) clearly identify the temperature requirements for reproduction as a critical bottleneck in the life cycle of fish. By 2100, depending on the Shared Socioeconomic Pathway (SSP) scenario followed, the percentages of species potentially affected by water temperatures exceeding their tolerance limit for reproduction range from ~10% (SSP 1–1.9) to ~60% (SSP 5–8.5). Efforts to meet ambitious climate targets (SSP 1–1.9) could therefore benefit many fish species and people who depend on healthy fish stocks.
Read more (paywalled): https://science.sciencemag.org/content/369/6499/65
The temperature excursion I was thinking of is the Younger Dryas, an abrupt return to ice age conditions just under 13,000 years ago, which lasted around 1200 years. The temperature shift was extreme (4-10C in Greenland), and occurred very rapidly, much faster than today’s mild global warming. The recovery was slower – but there were rapid periods of both warming and cooling.
Big freeze plunged Europe into ice age in months
… Carbon isotopes in each slice reveal how productive the lake was, while oxygen isotopes give a picture of temperature and rainfall. At the start of the ‘Big Freeze’ their new record shows that temperatures plummeted and lake productivity stopped over the course of just a few years. “It would be like taking Ireland today and moving it up to Svalbard, creating icy conditions in a very short period of time,” says Patterson, who presented the findings at the European Science Foundation BOREAS conference on humans in the Arctic, in Rovaniemi, Finland. …
Read more: https://phys.org/news/2009-11-big-plunged-europe-ice-age.html
One thing which did not happen during this period of wild temperature swings was the extinction of a large number of fish species.
“unable to cope with temperatures in their geographical range”
Evidence of fish migrating because of changing water temperatures exist even today, and have been known about for thousands of years.
Yet for some reason, CO2 will make fish forget how to migrate.
Yep, with the most prominent one being known as El Niño.
They just sit there and get cooked in the models.
Do fish migrate?
Yes, although sometimes they are just trying to find Nemo.
Only if they’re carrying coconuts.
“Climate change” cannot warm the oceans. Only the sun can do that. It needs fewer clouds to do that, but we are told that global warming leads to more clouds. Something doesn’t seem quite right!
You mean it smells fishy !!!
Yep, let’s not skate around the issue, it’s a load of pollocks.
Recall a very senior, well respected oceanographer was reported in a WUWT article a few years ago who advised that almost all lab tank experiments being done on warming, acidification, etc in the ocean were very badly designed, citing rapid heating, overly done acidulation, etc. He gave a list of details in such design that had to be considered in order to properly investigate issues for at least qualitative results.
I’m sorry gentle Drs of the Wegener institute, but you strike out on the magnitude of your temperature change at an impossible 5°C. So, here’s how it works. The surface temperature of the tropical open ocean cannot exceed 31C. This is the point where cooling evaporation is in equilibrium with SST more heating simply increases the evaporation rate, creates more cloud shade and cooling thunderstorms. Indeed, tropical regions change little even with ice age maxima.
Most of the swing is at the poles. Tropical fish will expand to occupy a wider band and temperate region fish will swim poleward, a thing you can’t do with your few cubic meter tanks. Ergo, a warmer world will have more fish. I hope this helps.
Malthusians have a petri-dish mentality of the helplessness of humans, let alone fish, so how they design experiments gives extreme results.
Most of water warming is caused by more sunshine. So in lakes you may have the problem of O2 shortage, on the one hand, because plants in water are more affected by warmer water and may die producing less O2 and on the other hand by more bluealgae, destroying plants no more able to produce O2.
“Our analysis shows that spawning adults and embryos consistently have narrower tolerance ranges than larvae and nonreproductive adults and are most vulnerable to climate warming……Scenario-based climate projections considering the most critical life stages (spawners and embryos) clearly identify the temperature requirements for reproduction as a critical bottleneck in the life cycle of fish.” There are probably more than 30,000 species of fishes, larvae have to deal more than eggs and adults with viscosity problems, something to do with temperature.
Pay walled, but wonder if they know about this paper on temperature shifts in the 30s, rediscovered. Oviatt, C. A. 2004. The changing ecology of temperate coastal waters during a warming trend. Estuaries. 27(6):895-904. https://doi.org/10.1007/BF02803416
“In the temperate North Atlantic Ocean the ecological changes in coastal waters associated with a warming period in the 1930s were compared with the past couple of decades when the North Atlantic Oscillation was also positive. Long-term monitoring data sets from Rhode Island and nearby coastal waters were used to identify trends in the recent warming period. During both events winter water temperatures warmed above a mean value of 2.9°C from 1°C to 3°C.”
So much of life is on a knife edge. Makes me wonder how it ever got started.
Or how the first drought or heat wave hasn’t killed them all off. These must be like Willis’s walking dead with covid.
“In a worst-case scenario of 5°C of global warming…”
RCP8.5 strikes again! With even Hausfather disavowing this absurd scenario, when are supposedly serious journals going to stop printing, or even reviewing, papers based on this nonsense.
“Even if humanity meets the Paris deal’s tough goal of holding warming to 1.5°C, it would be too hot for 10 per cent of fish. “
Paris deal was tough?
Tell that to China, India, Pakistan, etc. Countries were allowed to set their own levels of compliance to reduce the atmospheric CO2 levels. Any county (Pakistan for instance — This was Pakistan’s proposal: Pakistan’s pledge was to “Reach a peak at some point after which to begin reducing emissions.”) effectively could set a no change policy (or an increasing until whenever) and stick to it and that was fine.
(https://theruggedindividualist.wordpress.com/2018/03/21/did-any-of-the-media-actually-read-the-paris-accord/ )
Only the dumb-a$$ western nations competed to outdo each other in the virtual signaling game they play, much to the cost of their citizenry.
To think tax payers footed the bill for their “research”.
Yawn. Another day, another “It’s worse than we thought!!!” claim.
It’s like they’ve never heard of Aesop’s Fable, “The Boy Who Cried Wolf”. After a while people pay little attention.
(Alarmists will point out that in the story, the wolf eventually came. But in the story, the wolf was real and it had come before.)
So what?
Cooking oil on a stove at 250 degrees already helps kill a few % of fish each year. Geoff S
It’s alright all the polar bears, penguins are birds are dead under the same stupid argument so there is about the same percentage for us to eat.
If tens of thousands of years of solar radiation hasn’t managed to raise ocean temperatures to over around 35 C then I don’t think it likely to suddenly start raising this temperature now.
Have these scientists ever tried boiling a pan of water with a blow lamp on the surface?
Extrapolating their findings up to conjectures on the climate is highly unprofessional and damaging to the reputation of science.
I guess we can all relax then, especially fish. When has a worse case climate prediction ever happened. Very few basic predictions ever happen , hence the IPCC’s perpetual revisions towards awkward reality.
I predict most ‘Climate Scientists’ will have died before any of their predictions come true .
Fact: 100% of fish alive today will be dead before this could possibly happen. In the mean time evolution will allow most of their species to adapt and thrive regardless of which way the trend goes. And if they can’t adapt then new species will evolve to replace them. Thus it has always been.
The scam going on here is the climate alarmists treat CAGW as a step function. Completely unrealistic even if one believes the junk science of model projections.
Globally, sea temps will rise very slowly and unevenly, some areas warmer, some areas colder. The fish and all the species in the oceans and above it will adapt and shift and evolve just as they have for hundreds of millions of years of climate change more extreme than the junk models forecast.