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.
…
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.
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Do they say how much they think the water is going to warm? Even 5C of air temperature I wouldn’t think it to much of an effect on SST
The sun warms the water. How fast that heat is transferred to the atmosphere is in part regulated by the temperature of the air.
Max open ocean SST 31°C. Evap cooling in equilib with Sst at 31. More heating, just more eapud evap, cloud formation and cooling thunder storms.
Not all of the oceans can be found in the tropics.
97% of Climate Scientists can’t cope with a few degrees of warming
100% of Klimate Hactivists can’t pass up the opportunity to incite violence to overthrow government
I think Gary’s point is that sea surface temperature is limited to about 31C by evaporative cooling. Which means that tropical fish won’t need to adapt to anything warmer than that. Everywhere else, it should just mean that species might shift their range pole-ward to cooler waters.
Why would we assume that they will stay put until they die? Also why assume that the rate of warming could possibly be so fast that the fish could not easily adjust their range gradually?
I suppose that there may be situations where the food chain needed to support a species might not be present in the cooler regions adjacent to their old range. Also fish changing their range could have a serious impact on fishing communities. But assuming that most of the fish will die just doesn’t make sense.
Not if they are predicting that 5C by 2100. The Great Lakes would be hard pressed to show that much warming over such a short period, much less the Oceans.
Less then half of all fish are freshwater fish. Ocean fish aren’t going to be in much danger from this, at least in the next century, even IF their worst case happens.
I wrote this to another post: Pure water has more than 3000 X the heat in dry air at equal volume, temperature and pressure.
True, but hardly relevant.
Why isn’t it relevant?
Their is very little “Pure Water” existing in the natural environment
Most of it is contaminated with Salt
Only 0.5% is considered “Fresh Water” but Fresh doesn’t equal Pure
Salt water etc has still 1000’s of times more heat than air. Very simply put air can only have a minute effect on water temperatures. That’s the laws of thermodynamics. Sea Temperature records of the last 60 years bears this out
Salt water has 1000 of times the heat of air. If you have a liter of salt water its 1000 grams of mass or 2.2 lbs on the other hand a liter of air is between 1 and 2 grams. Water molecules are polar unlike air think sticky. It takes a lot more heat to get water moving aka heat/temperature. That’s thermodynamics as learned by chemists like me. So air can’t heat up water that’s the laws of thermodynamics
Mike, not sure if your point is relevant. The article is about the idea of 5C of total, globally averaged warming of the temperature, be it lower troposphere or at surface level.
How water surfaces warm and currents move the heat content, would be yet another story. You seem to oppose the idea of thermal conduction in this context but there’s also still direct absorption of energy from the sun. Also keep in mind a dynamic model of both massive water and air currents when compared to a static conduction test.
John Dowser fish live in the water not in the air. Air temperatures are irrelevant water temperatures are relevant. A 5C rise in air temperatures would have little effect on water temperatures. Ergo fish would be unaffected. I posted this here because there was no option to reply to his reply
Zebra muscles may die, which would be good, yes? Isn’t there something else that’s affecting fish populations?
What if the sky really did fall, and it was our fault? Then we’d be sorry!
So if you are that convinced that means you need to overthrow every government now … like today. Wish you luck 🙂
So 60% of the fish died during the Holocene Optimum?
No , they migrated. Like they will migrate this time if it get too warm where they are.
How far would shoal of fish have to migrate to find 1.5 deg C cooler? That is not even year to year variability. This is just more alarmist horseshit.
They drop this little get out clause in but then ignore for the rest of the paper like it is obvious that 60% of all fish species would stay in the same place where they cannot reproduce rather than move and then we’d all starve to death ourselves …. UNLESS we do as we are told !!
They don’t have to migrate, they just have to swim a few feet deeper.
That’s true if they still have a food supply at that depth. And if not they “migrate”. It’s more like diffusion. Fish that randomly swim into inhospitable waters are going to tend to swim back toward their preferred conditions. That will happen at all edges of their current range.
If that range of hospitable conditions slowly shifts toward the pole, the fish don’t hold a convention to decide on whether to set up a migration committee. They don’t all need to apply for visas to enter a new territory. Each fish acts autonomously to stay in hospitable waters, in realtime.
Good God, isn’t this obvious?
We have the correct answer .. they can also undergo behavioural adaption.
There is a large group of animals (poikilotherms) that already do it.
Yes… they migrate. To suitable T waters. Kinda like people to suitable T air.
BUT Worrrall’s research centered about the super-cute fishy in their picture. He is so adorable and delicate that he can’t survive anywhere except a temp-controlled fish tank set at 76°F ± 0.4°. This is why the authors are so paranoid.
So even under water it’s a jungle out there where survival of the fittest reigns.
I wonder what 5 deg C increase in atmospheric temperature translates to in ocean, or big lake, water temperature? Maybe 1 deg C change in the water? Ocean currents swirl around and change the ocean water temperature far more than that, and no pasa nada. Still freezing my patootie off here in Argentina, waiting for that global warming deal to kick in.
Not even. Pure water has more than 3000 X the heat in dry air at equal volume, temperature and pressure
No worries. At least warmth-loving large-mouth bass will survive. Yum!
That number sounds fishy to me.
Oh my cod it’s worse than we thought.
Better ask the Codfather to intercede.
“ Previously, we thought…”
AKA: Science is Settled unless we can find/invent stuff that shows we are worse off.
“…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…”
Really? They didn’t know that “embryos and spawning adults are more susceptible to warming oceans” and just started studying them?
The factor has gone from 5% to 60%… twelve times… more than an order of magnitude.
In other words, from (yawn + risk of being defunded) to (OMG + need more funding).
On a related note, the quality control and attention to detail on display suggests the “climate science is settled consensus factor” could be anywhere between 8.1% and 1164%.
We have a commet and a koi in a cut-off 45g drum outside with temp ranging from 25 to 0 over the year, with day to day variability of several degrees in less than 24h. Plants also doing fine. I do make sure the tank is not heated by direct sun on the side. They are now in their 3rd year with no problems now they have a steel grid to keep out racoons.
Are they having a hard time coming up with new things to fear? Is that why they have to recycle the oldies?
https://tambonthongchai.com/2018/05/23/fishing-for-climate-calamity/
Chaamjamal – This latest generation seems to feed on fear. So would anyone raised by the current crop of teachers, parents, politicians, the press, etc. Their generation will someday be known as the ‘frightened’ generation.
they just said 60% of fish made a bad evolutionary choice…..it’s darwin
damn planet has been too stable….that’s the whole problem
Good, I hope they all die. I don’t want to eat unlucky fish. You don’t know where they might have been.
They severely underestimate the worst case. Nothing and nobody can survive the worst case 🙂
Apparently the worst case is worser than we thunk.
This does not pass the smell test. Prior to the current ice age, the oceans were significantly warmer. The fish that need cooler water just go to where the water is cooler. The rest adapt. The ocean temperatures change by more than 1.5°C seasonally, and due to El Niño, etc. This does not cause extinctions. The fish relocate if they need to. The major cause of relocation of fish off of South America during an El Niño event is the nutrient-rich upwelling water is replaced by warmer but less rich water flowing east along the surface. It is not the temperature that bothers the fish, it is the lack of food down the food chain due to less nutrients in the water.
It does my heart good to see that the Bad News Industry™ is still busily churning out foregone conclusions. Those selfless, brave souls just keep on modelling away, even in the middle of the covid pandemic, ensuring that no one gets complacent about the future of the planet.
“We are the Bad News Industry™. We adhere to the scientific method: – if it ain’t worse than we thought, we go back and model it again!”
I’m not sure I agree with this, at least for ponds, rivers, and lakes. Crappie spawn in the spring when the water temperatures reach around 60degF (or perhaps one to two degF hotter). It’s highly doubtful that river and lake water won’t get below 60degF in the winder so the spawn should happen just as it always has. The timing might change slightly but that won’t affect the actual spawn. The eggs will hatch in about a week and the fry will emerge. From then on it is predators that affect the future population, not temperature. The temperature won’t matter unless it gets hot enough to fry the fry so to speak.
It’s the same for all kinds of freshwater fish.
I’m not well versed on seawater fish but I am aware that bluefin tuna spawning is related to water temperature and they like to spawn in warmer water – which also helps the survival of the offspring. If the oceans warm 5degC I would expect this to do nothing more than change the timing of the spawn but not the survival of the offspring. I just highly doubt the oceans are going to get so warm in the winter that it will never get cold enough for the bluefin to ever span. Again, the biggest killer of the offspring will be predators and not the water temp.
This study abstract says it was based on ” observational, experimental, and phylogenetic data” but it’s not obvious that the study was empirical. Instead it sounds as if it is hypothesis based. I.e. “If it gets too hot the spawns won’t happen”. Does the study actually include sea temperature trends that show the oceans, rivers, and lakes are going to get too hot for the fish to spawn?
Wow, great analysis!
We’re home-free only 40% of fish die off, right?
kool; sign me up for a coal-powered pickup truck
I don’t think Tesla are making pickup trucks yet.
How can they call themselves scientists? See Donna Laframboise on the corruption of the IPCC
Did 97 per cent of the fish they surveyed agree this consensus position or did they lose the majority of ballot papers again?
My three pond fish say they never got their ballot vote.
Anybody have information on how much warming has occurred over, say, the last 100 years for ocean waters below the thermocline as compared to the ocean layer above the thermocline?
“Thermocline, oceanic water layer in which water temperature decreases rapidly with increasing depth. A widespread permanent thermocline exists beneath the relatively warm, well-mixed surface layer, from depths of about 200 m (660 feet) to about 1,000 m (3,000 feet), in which interval temperatures diminish steadily.” — https://www.britannica.com/science/thermocline
If surface water fish feel a need to cool off from “global warming”, they just need some short periodic visits down to the thermocline. /sarc
“Fish are so important for human nutrition, so this study makes a strong case for protecting our ecosystems and natural environments.”
FIFY: “State repression of individual liberty is so important for long-term power, so this study makes a strong case for Stalinism v2.0.”
Let me guess without reading: an RCP8.5 climate input to the ecological model?
Chaam…
Good one!
Control freaks run out of fearful ideas.
I’m confident that they will soon run out of lies.
After all, they are already out of half-truths.
It’s the Guardian. ‘Nuff said.
Amazing, innit. We humans have the power to “stop climate change”, but can’t manage to produce enough toilet paper for everyone (and their storeage closet).