Climate refugee cod

Even more it’s worse than we thought~ctm

From Eurekalert

High probability for loss of breeding grounds if temperature increases by more than 1.5 degrees

Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research

The latest research conducted by AWI experts that the chances of survival for the offspring of important fish species will dramatically worsen, if the 1.5 ° C target of the Paris Climate Agreement is not achieved. Under conditions of further warming and acidification of the ocean, Atlantic cod and its arctic relative polar cod would be forced to look for new habitats in the far north. Their populations could dwindle. If so, this could be disastrous, as the polar cod is the most important food source for Arctic seals and seabirds. In addition, fishers could lose the world’s most productive area for catching Atlantic cod, located to the north of Norway. However, the results of the study also show that a stringent climate policy could prevent the worst consequences for animals and humans.

There are some types of fish that prefer extremely cool water – and can only spawn in cold water. The Atlantic cod, a well-known and favourite food fish, is one of them. Even better adapted to the cold is the polar cod, which overwinters in the Arctic in large swarms below the sea ice. The polar cod spawns at water temperatures between 0 and 1.5 degrees Celsius, because the fertilised eggs / the embryos can best develop at this temperature. In contrast, the Atlantic cod spawns at 3 to 7 degrees, which, from a human standpoint, is still extremely cold. The AWI researchers Flemming Dahlke and Dr Daniela Storch are convinced that this dependency on cold water could prove fateful for both species; as a result of climate change, especially the waters of the North Atlantic and Arctic will warm considerably unless human beings find a way to massively reduce emissions of the greenhouse gas carbon dioxide. In addition, there is the problem of acidification: the more carbon dioxide finds its way into the atmosphere, the more carbon dioxide dissolves in the ocean. Carbon dioxide bonds with water to form carbonic acid, which acidifies the ocean as it decays. “That means Atlantic cod and polar cod will be doubly stressed in the future: their habitat will simultaneously grow warmer and more acidic,” explains marine ecologist Flemming Dahlke.

He and project director Dr Daniela Storch, as the first researchers worldwide, have now used painstaking experiments to investigate how a simultaneous acidification and warming would affect the eggs of both species. In this context, the two AWI experts have especially concentrated on the embryos’ development up to the point where they hatch as larvae, only a few millimetres long. During this stage, they are especially sensitive to changing environmental conditions, which climate change could realistically produce. The researchers’ findings are sobering: in both species, even a small rise in temperature can cause the eggs to die or produce deformations in the larvae. “As we can see, the embryos are very sensitive, especially in the early phase of their development,” says Flemming Dahlke. As the experiments clearly show, the situation becomes even worse when the water is acidic: the number of embryos that don’t survive increases by 20 to 30 percent at a pH level of 7.7, even at optimal temperatures.

In addition, the two AWI researchers’ work is unique in that they combined laboratory findings with established climate models. The models predict the extent to which temperatures in various waters will be affected by climate change, and how much they will acidify. In turn, thanks to their experiments the two researchers can now precisely determine in which areas the Atlantic cod and polar cod will no longer be able to spawn in the future. It also becomes clear that we could see shifts in fish populations, because the adults will have to search for new spawning areas where their eggs or embryos can still find viable conditions for normal development. In this regard, Dahlke and Storch have chiefly considered three climate scenarios: the business-as-usual scenario, in which there is no meaningful reduction in carbon dioxide emissions by the end of the 21st century; a climate scenario with moderate warming, and a scenario in which the IPCC’s 1.5-degree goal – according to which the Earth’s temperature can’t be allowed to increase by more than 1.5 degrees in order to avoid the worst effects of climate change – is achieved. Working together with climate modeller Martin Butzin from the AWI, they arrived at some interesting conclusions. According to Flemming Dahlke, “They show that, for the business-as-usual scenario, conditions for the young Atlantic cod will especially deteriorate in the North Atlantic near the end of this century. In the regions around Iceland and Norway, up to 60 percent fewer cod larvae will hatch from their eggs.” Generally speaking, the Atlantic cod populations in the Northeast Atlantic will likely shift into the Arctic, where the spawning grounds still offer adequate conditions. This could especially pose problems for the fishing industry, since the coasts of Iceland and Norway are currently home to the world’s largest populations of Atlantic cod: Every year, around 800,000 tonnes of cod worth 2 billion euros are harvested here. If these populations dwindle, as the AWI experts’ findings indicate, the losses could be enormous.

What’s more, the business-as-usual scenario also looks bleak for the polar cod. If the waters grow warmer, it will retreat north, not only for the business-as-usual scenario but also under the scenario with moderate warming. Since the polar cod depends on sea ice for its overwintering phase, it remains to be seen how the populations will be affected if the sea-ice extent continues to shrink. Nor is it clear to what extent the Atlantic cod will encroach on the polar cod’s territory. Given the fact that the Atlantic cod is considerably larger and more aggressive than its polar cousin, the latter may have to fight for its food. Whether or not that happens, a drop in the polar cod population would be catastrophic, as it is a staple food for many organisms in the Arctic – including seals, seabirds and even whales.

The limits of fish species’ distribution also depend on where the prevalent temperatures are optimal for spawning. Dahlke and Storch’s experiments have for the first time confirmed that acidification makes fish embryos more sensitive not only to higher temperatures, but also to lower ones. “We’ve observed that the young Atlantic cod not only react adversely to warmer temperatures, but also to especially cold ones,” says Daniela Storch. “The acidification amplifies this effect.” In other words: the added burden of acidification reduces the suitable temperature range for Atlantic cod and polar cod to spawn. As Flemming Dahlke relates: “The fish become more sensitive to extreme temperatures, and consequently to the anticipated warming.” This would ultimately mean that the two species’ potential spawning grounds shrink, and that they might have less available habitat.

Flemming Dahlke stresses that, though the experiments yielded very clear findings, predicting the development of fish populations is extremely difficult. “For instance, whether or not the embryos and larvae survive also depends on the ocean currents and available food.” The Atlantic cod now spawn near Lofoten, an archipelago to the northwest of Norway. The current takes the eggs floating in the water, and later the larvae, farther north, where ideal living conditions await them. “If the Atlantic cod populations and their spawning grounds shift to the northeast in the future, the fish will most likely spawn in completely different systems of currents,” Dahlke explains. “If that happens, we can’t yet begin to gauge the effects.”

There is also good news, says Daniela Storch: “Achieving the climate goals of 1.5 ° C can prevent the worst, maintaining important spawning areas and minimizing the risks of both species.”

###

Original publication:

Flemming T. Dahlke, Martin Butzin, Jasmine Nahrgang, Velmurugu Puvanendran; Atle Mortensen, Hans-Otto Pörtner and Daniela Storch: Northern cod species face spawning habitat losses if global warming exceeds 1.5 °C. DOI: 10.1126/sciadv.aas8821

This work has been conducted in the frame of the BIOACID project.

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71 thoughts on “Climate refugee cod

    • Not decades, millennia. Anyone can do the math, the volume of the earth’s oceans is 1.335×10^21 litres of water, 4,184 Joules to raise a litre up 1 degree = 5.59×10^24 Joules. Back when the hiatus was the topic, there was a “find the missing heat”, sea level were rising so then it must have been expansion of the oceans is where the missing heat is going, “92% of all heat end up in the oceans”. Claims of 2×10^23 Joules added since 1970 so over 48 years. So it would take 1340 years to go up a degree at today’s warming. But that hypothesis has been battered by the last 3 years warming and cooling without much sea level rise. Now, if what they said was true, where did the heat go. If the heat is still going into the oceans does that mean an increase in ice on the world’s ice sheets? Or is the ice sheets still melting but the oceans cooling?

      • Yes, and the heat carrying capacity of the atmosphere is 0.1% of the oceans. The atmosphere does not control the temperature of the oceans. The oceans control the temperature of the atmosphere.

        • An additional point:

          “In contrast, the Atlantic cod spawns at 3 to 7 degrees, which, from a human standpoint, is still extremely cold.”

          The pelagic depths are guaranteed to be at 4°. Water that is warmer , or colder, than that is less dense and rises.

          • Sigh. This has probably been covered a hundred times on WUWT.

            It does not apply to salt water, only fresh.

      • Keith Rowe,

        The heat is not distributed uniformly throughout the ocean. For example,
        “Although global mean sea-surface temperatures are rising at only about half the rate as that for land, 0.13°C per decade compared to 0.27°C per decade since 1979 [10], increasing temperature is the most pervasive of present-day impacts on marine systems [34]

        “Although global mean temperature is rising, and other physical factors are changing (Figure 1), the scale of impact is not and will not be distributed evenly geographically [7] (Figure 2). Temperatures throughout the Arctic Ocean have risen since the 1950s, by more than 4°C in some places, whereas around Antarctica some locations have warmed while others have cooled (sea surface temperatures in the Weddell Sea have decreased by 2°C but have warmed by 2°C at South Georgia [48]). The East Australia Current has increased its southward penetration by about 360 km over the last 60 years, and average temperatures in affected regions have increased by more than 2°C in that time [49]. These regional variations will be of major importance to local inhabitants.”

        https://ars.els-cdn.com/content/image/1-s2.0-S0960982209011816-gr2.jpg
        https://www.sciencedirect.com/science/article/pii/S0960982209011816

          • tty,

            But it is relevant to Keith’s comment that the absorbed heat is not uniform throughout the oceans. I didn’t say anything about the cod.

  1. They still miss the elephant in the room, modern fishing technologies. Cod sexually mature earlier now because of over fishing.

  2. pH 7.7 “acidic”. They don’t even mention how much warmer the water might get if the atmosphere increases by 1.5C. The whole thing is a waste

    • By weight, the co2 went up from 0.0003 to 0.0004, you can see how partial pressure is causing the oceans to become more acidic. If we are responsible for all of the increase, that is.
      Even a slightly warming ocean, at least in the top layers, is going to release a lot more co2 than it takes in. So how is the ocean going acidic? They can’t have it both ways, it’s either the oceans are warming… oh, no releasing additional co2, ( that’s going to skew the entire humans are responsible for global warming via co2 meme) or going colder absorbing more co2… oh, no, where’s the heat hiding?

      • The answer is SHUT UP AND PAY FOR MY CARBON TAX!!!!

        If you pay for the carbon tax then the oceans will be totally fine as will the fish.

  3. How did these fish and their predators ever survive the past warm periods? Is this study saying that an increase of 1.5 degrees will make their breeding grounds hotter than they have ever experienced? Is this study assuming that a 1.5 degree increase in the global temperature will mean a 1.5 degree everywhere, including this location? If so, why can’t we just use one thermometer to determine global temperature rise?

  4. A 1.5 degree increase in global air temperature does not translate to a 1.5 degree increase in ocean temperature in the places where cod breed.

  5. There is so much wrong with this research I am surprised any institution would put its name to it. As above ph 7.7 is not acidic and the oceans will take hundreds of years to warm 1.5 degrees and even longer for the ph to lower that much. The cod will just move to colder waters if that happens anyhow and other species will fill the gaps, after all they can swim!

    Is the AWI an arts institution as it sure as hell doesnt produce science

  6. Hey. I’ve got an idea. Let’s take some fish eggs and put them in a hot acid bath and see if they thrive.

    Don’t laugh. That’s what they did. Going from pH8.1 to pH7.7 is a lot towards the acid side. 1.5 degrees C is a lot of ocean warming. For the Polar Cod environs it would also have to include melting all the ice.

    Stovetop “science.”

    • On the plus side, a lightly cooked cod fillet with some lemon butter makes a nice lunch. It’s great when your research feeds both your bank account and your belly.

  7. I once did research of this sort to measure affects of “acidification” on fish as an undergraduate. I suspect the laboratory conditions are so far from reality that the results are nearly meaningless, and this combined with their reliance on climate models that similarly lack any resemblance to the real world. As other commenters mention, their conclusions are completely at odds with the knowledge these fish species have thrived through much warmer periods in the past.

    • Can you imagine how many species would stagnate and die off if there were NO climate change? Who’s the denier?

    • Salute!
      I guess these “millennium” cod have forgotten how to swim a hundred miles to reach their nirvana temperature for, well, spawning.

      Meanwhile we just accepted a few dozen frozen turtles from Cape Cod, and they will do fine here in the Panhandle, despite Michael’s impact on the beaches The turtles bought into Gorebull Warming and stayed up near Maine longer than normal before their annual swim down to the Gulf.
      Gums sends…
      .

  8. Carbon dioxide bonds with water to form carbonic acid, which acidifies the ocean as it decays.

    ..and the carbonates in the ocean buffer it and stop that from happening

    The latest hype is the gulf stream is slowing down….so less warm water…more cold water

    …and they all contradict themselves constantly….it’s so settled

    • The ocean is not “acidified.” It is more correct to say it becomes less caustic – not very alarming at all. The study seems to indicate that Lutefisk may become more scarce – a big deal in that part of the world. /s

    • “The latest hype is the gulf stream is slowing down….so less warm water…more cold water”

      They’ve been trying that for at least 30 years. Not even close to “latest”.

  9. Can someone help me understand how a) warming oceans are supposed to ‘outgas’ CO2 (colder water can, as I recall, hold more CO2), and yet b) higher CO2 in the atmosphere will work its way into said warming oceans? These assertions seem at odds with each other. Anyone have graphs from experimental observations (not models) showing how this works? Thanks and sorry for the ignorant question.

  10. Haven’t fish species always moved ranges in response to sea temperature changes? I’ve always thought that there are recorded instances species “disappearing” and then returning when things change back.

    • And Polar Cod was then the only cod species around Grenland until the 1930s when warming casused the Atlantic Cod to recolonize greenland waters.

      And back during the Ice Age Polar Cod was dominant at least south to the North Sea-Baltic and the Champlain Sea.

  11. I’m probably not going to bother to dig further into the following, but I always think it’s funny when a “the sky is falling”-type article lets very important pieces of countervailing information leak out.

    **********

    Warning for Seafood Lovers: Climate Change Could Crash These Important Fisheries

    https://insideclimatenews.org/news/28112018/atlantic-cod-climate-change-fish-population-crash-risk-arctic-food-web-impact-study

    “In the Barents Sea, there have been shifts in populations. The Arctic fish communities are retreating,” he said. During a temporary regional ocean warming phase in the 1940s, Atlantic cod populations shifted northward by almost 1,000 kilometers, showing how fast and dramatic climate impacts can be, he said.

    **********

    Who knew? I certainly didn’t, not until I read this article.

    So some rather sudden and dramatic warming happened back in the 1940s, but the cod shifted/adapted, then shifted/adapted back when that warming went away. (And maybe any current warming is just as temporary.) Hardly a concern then for a potential “crash” situation; I expect that overfishing is the far more urgent danger.

    • IT WAS JUST TEMPORARY AND REGIONAL AND TOTALLY CAUSED BY HUMANS!!!!!!!!

      My political science professor told me so.

  12. IIRC Tonyb provided some history of fishing in Europe. Fishers had to search for cod and found them further north. Hope Tony can easily add that historical piece here.

  13. So how did they “survive” the Medieval Warm Period or the warm period around the time of the Romans exactly? More alarmism dressed up as pseudo science, the gutter standard now required for publication amongst the climate industry pretenders wanting their noses in the troff. Incredible to think there was no climate change before 1850 and no extinctions before man, or so their feeble minded marxism would have you believe.

  14. I recall posting some of this previously, but recall going to an American Fisheries Society meeting in Halifax in 1995 when National Geographic said that the fishery was doomed or something like that. There was an ignored paper, maybe two, on temperature changes. I went back in 1997 around Nova Scotia, overall fishery seemed good, lots of lobster.

    What was correctly originally researched was the difficult question of the role of predation (fishing) versus natural changes, especially on recruitment. This is an interesting quote from Scott and Scott (great scientists, who I met) 1988, “Atlantic Fishes of Canada.” “The year-classes of cod and haddock being fished in 1977 and the years immediately following were spawned in the early to mid 1970s. They proved to be of greater abundance by the time they entered the commercial fishery than had their immediate predecessors. Whether this was a result of management actions…..or of a naturally occurring change in the marine environment which allowed better survival during early life-history stages, has not been determined.” Now we know that the science is settled, but simulated fish don’t taste very good. It is a great book with thoughtful discussions on the fisheries and oceanography of the region. Also a great quote about science escaping a “Tower of Babel calamity. ”

    Shifts north and south were well known even well before WWII, have the papers around somewhere.
    I have a1947 or thereabout symposium on the questions.

  15. More junk ‘science’. In fertile cod locations, pH is now about 8.1 but varies seasonally when summer fresh meltwater intrusion lowers the surface value. Doubling dissolved CO2 would lower it to about 7.95 because of buffering. Fertile ocean pH could never reach 7.7.

  16. Take a look at “The Little Ice Age” by Brian Fagan.

    Northern Europeans have been following moving fish populations, triggered by changes in ocean temperatures, for centuries.

  17. Apparently Florida’s Manatees will probably become extinct when the remaining coal power stations close (unless action is taken).

    Anything under a water temperature of 17C and they risk hypothermia/death. In winter they used to rely on natural hot springs, but most of these vital locations have been destroyed/made inaccessible by development.

    Something like 80% of the Manatee population now relies on the warm water outfalls from the power stations and they mass there when they need the 24C warmth provided.

    Oh the irony.

  18. Cod evolved between 40 and 60 million years ago. How many times has the climate been much warmer than now and much colder than now in all that time. I don’t believe there is a climate threat to these fish, over-fishing is a completely different story!

  19. What always gets me about these cold water fish stories is how they Anthropomorphise the fishes.

    They always assert that the fishes or whatever aquatic critters ‘like’ cold places by simple virtue that they are Cold. Same way as we prefer Warm Places.

    I would say “Total Crap”
    The fish go where the food is, *exactly* as we do. Hence we don’t live in deserts, at the poles or really deep inside rainforests. There is nothing for us to eat in those places – we go to where the fertility is, where The Nutrients are. Where the food is.

    And I dunno what sort of picture they have of The Ocean but, get away from the continental shelves and it is another desert.
    The Nutrients in the ocean are in the coastal water coming off the land and *also* where water is upwelling from The Deep.
    Upwelling water has been trawling along the ocean floor for centuries acquiring nutrient off the ocean floor but is also, pretty well by definition, very very cold.
    Where it gets close to the surface and the sun provides some energy, then slime, plankton, shrimps, krill and other oceanic bugs & stuff multiply, feeding off that mineral nutrition coming up from The Deep.

    THEN, the Big Fishes come and eat them.

    Hence why fishes go to cold water – I do not for One Minute imagine they go there because they ‘like being cold. Not least they all contain fat of some sort or the other and it will start freezing in the cold, going into cold water will be as dangerous for them as us, except they operate on a lower (30 to 35 deg C) level to us.
    Cold is still bad.

    Unless these children are proposing that all oceanic upwelling ceases, they are doing Primary School Science mixed with a big splash of Disney sentimentality. Even before needlessly torturing critters inside (lab) experiments – EXACTLY as small children are want to do.

    Its all so poor.

    • PS and BTW, IF the ocean does haha ‘acidify’, because those nutrients all have basic or alkaline chemistry, the extra acid will effect to drag MORE nutrition off the deep ocean floor.

      An acidic ocean would thus ‘bloom’

      It is EXACTLY how nitrogen fertiliser works on farmland. The nitrogen does feed the plants directly to some extent but primarily feeds the soil bacteria.
      They ‘decompose’ soil organic material via a similar pathway to beer production and spoilage:
      ……sugar goes to alcohol goes to acid
      In the case of beer and wine, the acid is Acetic acid = vinegar.

      But in the soil a myriad different organic acids attack the mineral (basic/alkaline) part of the soil – releasing any/all of the 52 different nutrients that the plants need and use.
      Generally referred to as ‘Humic Acid’

      So it is in the ocean.
      An acidic ocean** will be a green and hugely productive ocean – esp. if it warms up a bit as well!

      Their heads would explode wouldn’t they?

      **Until pH goes below ~ 5.5 in which case all the heavy metal poisons start mobilising – EXACTLY as happens on farmland. Keep an eye on your local peasant. is he spreading ground limestone on his farm because if not, we/he are headed into BIG trouble

  20. As long as there are iced up poles there will always be cold water in meridional ocean circulation. It’s just a question of where to find it.

    This is just more ignorant lazy run-of-the-mill alarmist bollocks.

  21. I recall in Racial Carson’s book, “The sea around us”” she mentioned how the fish in the North Sea changed their location from time to time.

    Of course back then we did not have to worry about CO2.

    MJE

  22. “However, the results of the study also show that a stringent climate policy could prevent the worst consequences for animals and humans.”

    What a relief! It’s sooooooooooooooo convenient…

  23. If you pay up enough money into a stringent carbon dioxide tax, then all this multitude of problems will (eventually) go away and the body of CAGW Alarmism will be satisfied (eventually).

  24. Fortunately, unlike humans, animals are smart enough to seek out new habitats when conditions change.

    Humans just sit around bitching until governments take OPM and give it to them so they can stay in their dangerous locations.

  25. These people are utterly brainless with their catastrophic claims…. Cod have survived climate change in the last 20 000 years that has seen sea levels rise 120 meters. Many of the Cod Breeding grounds were dry land at that time… or had a kilometer of ice sitting on them.

    You get sick of this outlandish “science” after a while.

  26. “In this context, the two AWI experts have especially concentrated on the embryos’ development up to the point where they hatch as larvae, only a few millimetres long. During this stage, they are especially sensitive to changing environmental conditions, which climate change could realistically produce. ”

    If they hatch at that temperature it is only going to be an increase that affects them. Changing the conditions after hatching is not science. PETA should be informed.

  27. I recall a visit to Glacier Bay, Alaska, when the tour guide explained that water temps were cooler in the winter than in the summer. The reason was meltwater from the glaciers.

    Seems to me that if Arctic atmospheric temps increase, so will the summer melt from both sea ice and Greenland. Thus may not totally offset seawater warming, but certainly should have some counter effect.

    • Sorry, I meant that Glacier Bay water temps were cooler in SUMMER than winter. Got distracted while typing!

  28. The researchers’ findings are sobering: in both species, even a small rise in temperature can cause the eggs to die or produce deformations in the larvae. “As we can see, the embryos are very sensitive, especially in the early phase of their development,” says Flemming Dahlke. As the experiments clearly show, the situation becomes even worse when the water is acidic: the number of embryos that don’t survive increases by 20 to 30 percent at a pH level of 7.7, even at optimal temperatures..
    ___________________________________________________

    the next study will expose test sheep 6 different falling Heights to determine the resulting damages.

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