Thanks for the answer. I absolutely agree with you ! Especially this point :
Whenever human preferences collide with a resource limit, humans deny the limit or overcome it but externalize some harmful consequences.
Of course, this applies particularly well to our current growth-based civilisationāmany other human societies knew that ecological overshoot could prove deadly so they developed values that allowed better to stay within limits.
And I absolutely agree with your point. For most topics on ecology, there are thresholds upon which we trigger catastrophes : climate change, energy depletion, resource depletion, biodiversity loss, destruction of marine life, deforestation, water depletion, pollutionā¦ The threshold may be close for some causes, and far away for others, but this is not the main : in a society whose impact continues to grow as fast as possible, we inevitably cross this threshold at some point.
This is why our current civilisation is not sustainable.
We may try to solve one problem separately (say climate), but then we increase the damage caused in another area (more mining and resource depletion for renewables).
Our ocean health is in decline, and loss of it as a carbon sink in combination with loss of its biodiversity could destroy civilization.
Iām interested by this sentence. Do you have a few link on this topic ? Iād tend to agree but I havenāt stumbled on high quality sources yet for that statement.
As far as the statement, āOur ocean health is in decline, and loss of it as a carbon sink in combination with loss of its biodiversity could destroy civilization.ā
You can attribute it to me though I think itās uncontroversial in its current form[1].
Interpreted as meant, it has parts:
the oceanās health is in decline
if the oceanās health reaches a low enough level, then it will lose its ecosystem resource values for humanity (for example, its value as a food source).
if the oceanās health reaches a low enough level, then it will stop serving as a carbon sink.
if the ocean loses its ecosystem resources and loses its function as a carbon sink, then human civilization could collapse[2].
The statement you quoted does not say that the oceanās health will decline precipitously. I say that elsewhere.
I think beliefs 1, 2, and 3 are not that controversial but I can constrain them or give them nuance if thatās really necessary. Belief 4 is speculative which is why I wrote ācould.[3]ā
I have not read any source that says human pressure on the ocean has locked-in the destruction of ocean ecosystems, and only one source suggesting that within a short period of time, it could. That said, what specifically would you like sources for, among beliefs 1-4 above?
It becomes controversial if I write it as āwill destroy civilizationā or āWe will lose all ocean biomass.ā I do reluctantly believe that we will lose all (really most) ocean biomass, but that belief is contingent on human choices for at least several more years. If I see massive global change in a different and positive direction, then I will think differently about the future of the ocean.
I believe that the ocean will lose its biomass, primarily because of human neglect, but human civilization could survive that one stressor. That is only a theoretical outcome though because the causes of the oceanās decline in health also cause stress on human civilization in other ways.
I suspect there are links between ocean and terrestrial ecology that endanger terrestrial ecology if the ocean loses its plants and animals. Thatās a different and stronger stressor but I donāt understand the causes involved enough to comment on it.
The last statement contains the word ācouldā which does not indicate a likelihood but just an ambiguity between āwillā and āwill ifā. I keep that ambiguity in my language because some of the contingencies of the statementās truth are unknown to me. Furthermore, I am not making a forecast. If I were, it would be based on those contingencies and my beliefs about human behavior in the future.
I think I can agree with the reasoning. The same goes for land biodiversity: continuing the current decline (for which there is almost no trend of improvement) will at some point cause ecosystems fuctions to stop working and triggering a global catastrophe (when is more tricky).
I would have liked sources for number 4 but if I understand correctly thatās more of a logical conclusion you obtained on your part ? Then do you have sources for number 3 ? I feel this may be underestimated in climate models.
Belief 4 can be rephrased as: āpoor ocean health could lead to civilization collapse.ā
My use of ācouldā there is meant to communicate an ambiguity between two possibilities:
a pathway along which poor ocean health, in combination with other causes, is sufficient to lead to civilization collapse.
a pathway along which poor ocean death is sufficient to cause civilization collapse.
As I mentioned in a footnote, Iām interested in interactions between:
an ocean that loses zooplankton and capability to support most phytoplankton
terrestrial ecology.
human civilization.
Those interactions could cause civilization collapse along the second pathway or just contribute to the first pathway. The first pathway has additional causes that it requires, or preconditions at points along its causal pathway, to lead to civilization collapse.
Belief 3 is, as I think you noticed, open to interpretation. My intended meaning was basically that an ocean, absent the biological pump, has a simpler total flux of CO2 through it that does not provide a net carbon sink.
Ocean mesh models are not supported by small enough mesh sizes (about 1km, according to a recent podcast I listened of a climate modeler) to allow small-scale predictions of current, heating, and temp changes, so precise computer modeling of changes to PH, temperature, ocean currents, and areas of CO2 exchange with the atmosphere is not possible, but if the question is:
what happens to the ocean carbon sink if all the ocean plankton die off as the water heats up and PH drops and pollutant levels increase?
the answer is:
well, the ocean will cease to be a net carbon sink, and could become a net carbon source.
but if you find differently, let me know, and we can have the debate, and I will bring whatever sources I can to bear.
As far as I know, most scientific discussion of changes in ocean health are still speculative and meant to:
communicate lesser changes over longer time periods than a decade.
discuss concerning recent developments (for example, the recent happenings in the Eastern Mediterranean sea).
Thereās been some back and forth about how important the biological pump really is for net carbon flux, and I am tracking that down for you.
I think most of the questions are really about how to model loss of plankton in response to:
ocean heating,
acidification
overfishing
pollution effects.
After all, thereās still some doubt around whether changing ocean chemistry, temperature, toxin levels, and circulation will do much more than change species composition and get rid of some animals up the food chain. Even with pollutant effects, discussion of the sterilization of the ocean by unintended consequences of human activity is not common yet.
You seem to agree with the assertion that human civilization either denies resources limits or overcomes resource limits by externalizing harmful consequences, so let me share my further thoughts on that with you.
Resources can be supplied or recycled, but there are consequences to doing so. The limitation of EROI and Peak Resource concepts are that they set numerical limits on resource extraction but donāt seem to say much about whether itās a good idea to cross those limits if they are inaccurate or can be overcome somehow. (for example, would it be ok to extract more lithium, if it were there and energy to do so were available?).
I think the interesting perspective comes from considering what happens when people attempt to either deny or break through those limits, and then to follow the actual pathway of events and see if deniers or techno-optimists can create the future that they believed awaited them.
Are they proving themselves right after all?
Can they maintain lifestyles or build economies?
Are they improving the world as they claimed to want to do?
I have followed climate change and environmental concerns off and on since the 1990ā²s. Climate, ecology, and pollution concerns are not taken seriously, despite all the talk and attention, changes are not happening in the domains where it counts (resource conservation and family planning, mainly). Weāre decades too late for most of humanity with our current foolish approaches (renewables, replacing cars with more cars), staying under 1.5C GAST has failed, staying under 2C GAST will either fail or civilization will collapse, and thenā¦ it seems we will only respond to negative consequences.
Some EA folks think that because so much money is spent on climate change, itās not a neglected problem, but thatās clearly incorrect. Nothing defines environmental concerns more than the neglect that people show the concerns, at least as far as preventing them goes. Adaptation, mitigation, and externalization are what we attempt, mainly externalization.
Thatās just historically accurate, I mean, thatās how its been for the last 30-40 years.
As a problem, limits on shared resources punish externalization the most. Every extra bit taken by one party costs everyone else. Nevertheless, externalization continues.
The same is likely to happen with respect to resource limits of the kind youāve been documenting. The numbers might change a bit, or the specific resources that are in need, but there will be adaptation, mitigation, and externalization by some subset of humanity. Prevention has been left behind. A longer-term view of climate change was abandoned decades ago in favor of externalizing consequences, but people either donāt realize it or donāt acknowledge it.
In conclusion, the ethical agenda of those looking to prevent existential risk is at odds with how we treat resource limits. It shows in how we externalize consequences of our resource use. Iāve not seen any green agenda win before, in my lifetime, at a global scale, but itās priorities would reflect integrity and that might help in how it manages externalities. The well-known alternatives (denial and techno-optimism) tend to benefit the few at the expense of the many.
As for the links, do you have something on the declining health of the oceans that could act as a summary for āwe have a problem and it could be bigā. I donāt think Iāll go deep into this topicāI mostly want something that I can link to when I say a statement like āoceans health declining could be a very serious problemā.
I have followed climate change and environmental concerns off and on since the 1990ā²s. Climate, ecology, and pollution concerns are not taken seriously, despite all the talk and attention, changes are not happening in the domains where it counts (resource conservation and family planning, mainly). Weāre decades too late for most of humanity with our current foolish approaches (renewables, replacing cars with more cars), staying under 1.5C GAST has failed, staying under 2C GAST will either fail or civilization will collapse, and thenā¦ it seems we will only respond to negative consequences.
This is very true, Iām still surprised as to how so many people have a āweāll somehow find a solutionā mindset despite so little actually happening.
In conclusion, the ethical agenda of those looking to prevent existential risk is at odds with how we treat resource limits. It shows in how we externalize consequences of our resource use. Iāve not seen any green agenda win before, in my lifetime, at a global scale, but itās priorities would reflect integrity and that might help in how it manages externalities. The well-known alternatives (denial and techno-optimism) tend to benefit the few at the expense of the many.
This is true as well. The last sentence is particularly enlightening. A āgreen growth will workā stance is very risky, but we wonāt be the ones bearing most of the risk, as we have the money to go elsewhere and be protected by the negative impactāup to some point. So it will come at the expense of others.
All right, Iāll put together a list of links on ocean health.
What points of mine do you disagree with? Iām interested in your feedback. Have Heinberg and other Peak Resources people moved into degrowth strategies, or have a holistic take on resource use?
At this point, I see the fundamental problem less about how we are bumping up against limits as how we treat limits in general. Human civilization definitely tests them in damaging ways.
I am working on a list of links and a narrative to tie them together (one that suggests a serious problem), and will hopefully have something soon. Meanwhile, Iāl dump some links into this to show you where I am at.
The topic area is fairly complicated, and timing within a window of a decade or two depends on factors like rates of plastic pollution and predictions of overfishing given contraction of populations from other causes.
Thereās also some complicated science that I am still wrapping my head around, particularly to do with:
oxygen depletion
the lifecycle of various types of phytoplankton
micro-plastics as particulates.
Finally, thereās new problem indicators (like the cancellation of the snow crab season in Alaska this year, and why it happened), and each story about them gives the marine bio community reason to pause.
I would like to dig through the IPCC predictions of, for example, fish populations by the end of the century, and reconcile them with predictions I find in papers (for example, 60% population loss of fish populations due to temperature changes by 2100 under business-as-usual).
Thereās ocean tipping points (for example, average surface ocean PH of 7.95 according to one source), below which irreversible ecological changes occur, but those boundaries are not a consensus.
Then thereās whether humanity could leave the business-as-usual pathway by one of several plausible exit points well before the end of the century, but find itself on a pathway with the same (or worse) 2100 endpoint for the oceans because of intrinsic feedbacks, for example, due to:
carbon dumped from the ocean
sudden thaws of permafrost
rapid freshening of water around Greenland or even the Antarctic
changes in AMOC
Iām not a marine biologist (my undergradās in geophysics), but I have painted myself enough of a picture to get, in broad strokes, that marine life will perish under a business-as-usual carbon production and pollution production scenario.
Then thereās whether humanity could leave the business-as-usual pathway by one of several plausible exit points well before the end of the century, but find itself on a pathway with the same (or worse) 2100 endpoint for the oceans because of intrinsic feedbacks, for example, due to carbon dumped from the ocean, sudden thaws of permafrost
I agree, weāre pushing some massive changes into complex important systems we really have trouble understanding, this is usually a recipe for disaster.
Iām not a marine biologist (my undergradās in geophysics), but I have painted myself enough of a picture to get, in broad strokes, that marine life will perish under a business-as-usual carbon production and pollution production scenario.
This is a strong conclusion, but I can agree with it.
Just two questions :
Is your conclusion still valid given the estimates of greenhouse gasses that take into account fossil fuels depletion, like I point out at the end of post 2 (i.e. not IPCC models, closer to 2 to 3 degrees of warming) ?
Is pollution (like plastic or eutrophisation) strong enough to make marine life perish at a global level ? Or is it just very bad locally ?
OK, well, Iām running behind, having not read post 2 and having not yet linked up my last post, but if youāre asking whether we stop producing GHGās at 2-3C, then does that include methane and coal? Either way, it comes back to how fast and how much feedback kicks in between 2-3C GAST. Coal matters because thereās an aerosol effect associated with it that we already take advantage of, somewhere in the range of 0.5C degree GAST decrease, from what I remember.
Thereās global methane hydrate melting with slowing of the AMOC and heating of the water below the surface level, the earliest prediction for that from a tipping point expert is after 2C , I think thatās the link, the discussion comes up in the Q and A, itās worth watching. When AMOC slows is model-dependent, and the models donāt agree. I also came across a news article about a recent expedition that found a new methane vent in the laptev sea.
Then thereās abrupt permafrost thaw, wildfires in permafrost land acting as a positive feedback, and the eventual contribution of gradual thaw.
then thereās loss of terrestrial sinks. Need for biomass in an energy crisis will strip forests, drought will cause wildfires, disease will continue to harm forests, and damaging forest management policies, as in the Amazon, could do the rest.
The plastic problem is global. Fishing gear contributes a lot to the problem. My guess is that it gets dumped wherever fish are being harvested, but it could be the opposite. How much of an impact it has on ocean life depends on how much it scales, but notice there are waste streams from land and a separate waste stream of plastic from fishing gear. The fishing gear plastic pollution might be targeted, and possibly less of a matter of scale and more about where it is dumped. Or not, youād have to have a model of ocean circulation, plastic breakdown, and dumping areas to make sense of that. It would help to know how much of the increase in plastic use is burned, landfilled, or dumped at sea in future.
Thereās some discussion about PFAS pollutants, but the fundamentals are about ecology. Are there some pollutants that, if dumped once, could kill most marine life? I believe so, but Iām avoiding research of that topic on purpose for now, first because its about how to poison the ocean, and second, because the lesser cases with the same outcome rely more on marine ecology knowledge, something Iām still lacking.
Regardless of initial pressures on marine life, pressure on human food systems will lead to overfishing, as fisheries suffer declines, fishing fleets will cheat the system, and deplete populations. Between by-catch and abandoned gear, the fishing industry alone could destroy marine ecosystems as human population goes up and as pressure to cheat quota systems, for lack of food or to meet rising demand, also goes up. Not only will that lead to long-term fishery declines and even species extinction, it will lead to increasing amounts of fish that do not meet health and safety standards ending up on peopleās plates, before the fish are gone entirely. This is a bit of a tangent, but is important enough to explore on its own.
Another tangent is what contribution the ocean actually makes as a carbon sink. Iāve seen estimates from 25% to 40% (and one scientist claiming 50%), and the relevance of those numbers is a bit different. For example, the 25% is a historical account over the last few hundred years, whereas the higher numbers could refer to current sink contributions, but I have to track the higher numbers down to research sources.
Does killing off larger organisms lead to collapse of specific plankton populations? Thatās the bottom line as far as loss of the biological pump. Iām still working on it, I donāt have much time, so give me a chance, Iāll try to finish links on this comment tonight, and maybe get a few into the prior comment.
This is really about ocean tipping points as well, another research topic. Yeah, I need time.
Finally, thereās the possibility that leaving the ocean and coastlines entirely alone while reducing GHG emissions could increase the action of the biological pump enough to draw down our current GHGās and reduce GAST overall. By leaving the ocean alone we could undo climate change. But that would mean doing everything right. Not the usual for us humans.
Oops, I though I had answered this commentāsorry about the delay.
Thanks for the links, this is interesting. I am not sure I will dig into this topic right now but I might at some point when looking into ecological collapse, so this might provide a good start.
I was aware of the huge impact of discarded fishing gear on plastic, but probably neglected other impacts you mentioned.
But that would mean doing everything right. Not the usual for us humans.
Well put, exactly the problem. Every time there is an issue, whether social or ecological, someone says āyeah but we can do that to solve the problemā. But we donāt. Thatās the issue.
Thanks for the answer. I absolutely agree with you ! Especially this point :
Of course, this applies particularly well to our current growth-based civilisationāmany other human societies knew that ecological overshoot could prove deadly so they developed values that allowed better to stay within limits.
And I absolutely agree with your point. For most topics on ecology, there are thresholds upon which we trigger catastrophes : climate change, energy depletion, resource depletion, biodiversity loss, destruction of marine life, deforestation, water depletion, pollutionā¦ The threshold may be close for some causes, and far away for others, but this is not the main : in a society whose impact continues to grow as fast as possible, we inevitably cross this threshold at some point.
This is why our current civilisation is not sustainable.
We may try to solve one problem separately (say climate), but then we increase the damage caused in another area (more mining and resource depletion for renewables).
Iām interested by this sentence. Do you have a few link on this topic ? Iād tend to agree but I havenāt stumbled on high quality sources yet for that statement.
Hi, Corentin
As far as the statement, āOur ocean health is in decline, and loss of it as a carbon sink in combination with loss of its biodiversity could destroy civilization.ā
You can attribute it to me though I think itās uncontroversial in its current form[1].
Interpreted as meant, it has parts:
the oceanās health is in decline
if the oceanās health reaches a low enough level, then it will lose its ecosystem resource values for humanity (for example, its value as a food source).
if the oceanās health reaches a low enough level, then it will stop serving as a carbon sink.
if the ocean loses its ecosystem resources and loses its function as a carbon sink, then human civilization could collapse[2].
The statement you quoted does not say that the oceanās health will decline precipitously. I say that elsewhere.
I think beliefs 1, 2, and 3 are not that controversial but I can constrain them or give them nuance if thatās really necessary. Belief 4 is speculative which is why I wrote ācould.[3]ā
I have not read any source that says human pressure on the ocean has locked-in the destruction of ocean ecosystems, and only one source suggesting that within a short period of time, it could. That said, what specifically would you like sources for, among beliefs 1-4 above?
It becomes controversial if I write it as āwill destroy civilizationā or āWe will lose all ocean biomass.ā I do reluctantly believe that we will lose all (really most) ocean biomass, but that belief is contingent on human choices for at least several more years. If I see massive global change in a different and positive direction, then I will think differently about the future of the ocean.
I believe that the ocean will lose its biomass, primarily because of human neglect, but human civilization could survive that one stressor. That is only a theoretical outcome though because the causes of the oceanās decline in health also cause stress on human civilization in other ways.
I suspect there are links between ocean and terrestrial ecology that endanger terrestrial ecology if the ocean loses its plants and animals. Thatās a different and stronger stressor but I donāt understand the causes involved enough to comment on it.
The last statement contains the word ācouldā which does not indicate a likelihood but just an ambiguity between āwillā and āwill ifā. I keep that ambiguity in my language because some of the contingencies of the statementās truth are unknown to me. Furthermore, I am not making a forecast. If I were, it would be based on those contingencies and my beliefs about human behavior in the future.
Ok, this is interesting !
I think I can agree with the reasoning. The same goes for land biodiversity: continuing the current decline (for which there is almost no trend of improvement) will at some point cause ecosystems fuctions to stop working and triggering a global catastrophe (when is more tricky).
I would have liked sources for number 4 but if I understand correctly thatās more of a logical conclusion you obtained on your part ? Then do you have sources for number 3 ? I feel this may be underestimated in climate models.
Hi, Corentin.
Belief 4 can be rephrased as: āpoor ocean health could lead to civilization collapse.ā My use of ācouldā there is meant to communicate an ambiguity between two possibilities:
a pathway along which poor ocean health, in combination with other causes, is sufficient to lead to civilization collapse.
a pathway along which poor ocean death is sufficient to cause civilization collapse.
As I mentioned in a footnote, Iām interested in interactions between:
an ocean that loses zooplankton and capability to support most phytoplankton
terrestrial ecology.
human civilization.
Those interactions could cause civilization collapse along the second pathway or just contribute to the first pathway. The first pathway has additional causes that it requires, or preconditions at points along its causal pathway, to lead to civilization collapse.
Belief 3 is, as I think you noticed, open to interpretation. My intended meaning was basically that an ocean, absent the biological pump, has a simpler total flux of CO2 through it that does not provide a net carbon sink.
Ocean mesh models are not supported by small enough mesh sizes (about 1km, according to a recent podcast I listened of a climate modeler) to allow small-scale predictions of current, heating, and temp changes, so precise computer modeling of changes to PH, temperature, ocean currents, and areas of CO2 exchange with the atmosphere is not possible, but if the question is:
what happens to the ocean carbon sink if all the ocean plankton die off as the water heats up and PH drops and pollutant levels increase?
the answer is:
well, the ocean will cease to be a net carbon sink, and could become a net carbon source.
but if you find differently, let me know, and we can have the debate, and I will bring whatever sources I can to bear.
As far as I know, most scientific discussion of changes in ocean health are still speculative and meant to:
communicate lesser changes over longer time periods than a decade.
discuss concerning recent developments (for example, the recent happenings in the Eastern Mediterranean sea).
Thereās been some back and forth about how important the biological pump really is for net carbon flux, and I am tracking that down for you.
I think most of the questions are really about how to model loss of plankton in response to:
ocean heating,
acidification
overfishing
pollution effects.
After all, thereās still some doubt around whether changing ocean chemistry, temperature, toxin levels, and circulation will do much more than change species composition and get rid of some animals up the food chain. Even with pollutant effects, discussion of the sterilization of the ocean by unintended consequences of human activity is not common yet.
You seem to agree with the assertion that human civilization either denies resources limits or overcomes resource limits by externalizing harmful consequences, so let me share my further thoughts on that with you.
Resources can be supplied or recycled, but there are consequences to doing so. The limitation of EROI and Peak Resource concepts are that they set numerical limits on resource extraction but donāt seem to say much about whether itās a good idea to cross those limits if they are inaccurate or can be overcome somehow. (for example, would it be ok to extract more lithium, if it were there and energy to do so were available?).
I think the interesting perspective comes from considering what happens when people attempt to either deny or break through those limits, and then to follow the actual pathway of events and see if deniers or techno-optimists can create the future that they believed awaited them.
Are they proving themselves right after all?
Can they maintain lifestyles or build economies?
Are they improving the world as they claimed to want to do?
I have followed climate change and environmental concerns off and on since the 1990ā²s. Climate, ecology, and pollution concerns are not taken seriously, despite all the talk and attention, changes are not happening in the domains where it counts (resource conservation and family planning, mainly). Weāre decades too late for most of humanity with our current foolish approaches (renewables, replacing cars with more cars), staying under 1.5C GAST has failed, staying under 2C GAST will either fail or civilization will collapse, and thenā¦ it seems we will only respond to negative consequences.
Some EA folks think that because so much money is spent on climate change, itās not a neglected problem, but thatās clearly incorrect. Nothing defines environmental concerns more than the neglect that people show the concerns, at least as far as preventing them goes. Adaptation, mitigation, and externalization are what we attempt, mainly externalization.
Thatās just historically accurate, I mean, thatās how its been for the last 30-40 years.
As a problem, limits on shared resources punish externalization the most. Every extra bit taken by one party costs everyone else. Nevertheless, externalization continues.
The same is likely to happen with respect to resource limits of the kind youāve been documenting. The numbers might change a bit, or the specific resources that are in need, but there will be adaptation, mitigation, and externalization by some subset of humanity. Prevention has been left behind. A longer-term view of climate change was abandoned decades ago in favor of externalizing consequences, but people either donāt realize it or donāt acknowledge it.
In conclusion, the ethical agenda of those looking to prevent existential risk is at odds with how we treat resource limits. It shows in how we externalize consequences of our resource use. Iāve not seen any green agenda win before, in my lifetime, at a global scale, but itās priorities would reflect integrity and that might help in how it manages externalities. The well-known alternatives (denial and techno-optimism) tend to benefit the few at the expense of the many.
I agree with you on a lot of points !
As for the links, do you have something on the declining health of the oceans that could act as a summary for āwe have a problem and it could be bigā. I donāt think Iāll go deep into this topicāI mostly want something that I can link to when I say a statement like āoceans health declining could be a very serious problemā.
This is very true, Iām still surprised as to how so many people have a āweāll somehow find a solutionā mindset despite so little actually happening.
This is true as well. The last sentence is particularly enlightening. A āgreen growth will workā stance is very risky, but we wonāt be the ones bearing most of the risk, as we have the money to go elsewhere and be protected by the negative impactāup to some point. So it will come at the expense of others.
All right, Iāll put together a list of links on ocean health.
What points of mine do you disagree with? Iām interested in your feedback. Have Heinberg and other Peak Resources people moved into degrowth strategies, or have a holistic take on resource use?
At this point, I see the fundamental problem less about how we are bumping up against limits as how we treat limits in general. Human civilization definitely tests them in damaging ways.
I am working on a list of links and a narrative to tie them together (one that suggests a serious problem), and will hopefully have something soon. Meanwhile, Iāl dump some links into this to show you where I am at.
The topic area is fairly complicated, and timing within a window of a decade or two depends on factors like rates of plastic pollution and predictions of overfishing given contraction of populations from other causes.
Thereās also some complicated science that I am still wrapping my head around, particularly to do with:
oxygen depletion
the lifecycle of various types of phytoplankton
micro-plastics as particulates.
Finally, thereās new problem indicators (like the cancellation of the snow crab season in Alaska this year, and why it happened), and each story about them gives the marine bio community reason to pause.
I would like to dig through the IPCC predictions of, for example, fish populations by the end of the century, and reconcile them with predictions I find in papers (for example, 60% population loss of fish populations due to temperature changes by 2100 under business-as-usual).
Thereās ocean tipping points (for example, average surface ocean PH of 7.95 according to one source), below which irreversible ecological changes occur, but those boundaries are not a consensus.
Then thereās whether humanity could leave the business-as-usual pathway by one of several plausible exit points well before the end of the century, but find itself on a pathway with the same (or worse) 2100 endpoint for the oceans because of intrinsic feedbacks, for example, due to:
carbon dumped from the ocean
sudden thaws of permafrost
rapid freshening of water around Greenland or even the Antarctic
changes in AMOC
Iām not a marine biologist (my undergradās in geophysics), but I have painted myself enough of a picture to get, in broad strokes, that marine life will perish under a business-as-usual carbon production and pollution production scenario.
I agree, weāre pushing some massive changes into complex important systems we really have trouble understanding, this is usually a recipe for disaster.
This is a strong conclusion, but I can agree with it.
Just two questions :
Is your conclusion still valid given the estimates of greenhouse gasses that take into account fossil fuels depletion, like I point out at the end of post 2 (i.e. not IPCC models, closer to 2 to 3 degrees of warming) ?
Is pollution (like plastic or eutrophisation) strong enough to make marine life perish at a global level ? Or is it just very bad locally ?
OK, well, Iām running behind, having not read post 2 and having not yet linked up my last post, but if youāre asking whether we stop producing GHGās at 2-3C, then does that include methane and coal? Either way, it comes back to how fast and how much feedback kicks in between 2-3C GAST. Coal matters because thereās an aerosol effect associated with it that we already take advantage of, somewhere in the range of 0.5C degree GAST decrease, from what I remember.
Thereās global methane hydrate melting with slowing of the AMOC and heating of the water below the surface level, the earliest prediction for that from a tipping point expert is after 2C , I think thatās the link, the discussion comes up in the Q and A, itās worth watching. When AMOC slows is model-dependent, and the models donāt agree. I also came across a news article about a recent expedition that found a new methane vent in the laptev sea.
Then thereās abrupt permafrost thaw, wildfires in permafrost land acting as a positive feedback, and the eventual contribution of gradual thaw.
then thereās loss of terrestrial sinks. Need for biomass in an energy crisis will strip forests, drought will cause wildfires, disease will continue to harm forests, and damaging forest management policies, as in the Amazon, could do the rest.
The plastic problem is global. Fishing gear contributes a lot to the problem. My guess is that it gets dumped wherever fish are being harvested, but it could be the opposite. How much of an impact it has on ocean life depends on how much it scales, but notice there are waste streams from land and a separate waste stream of plastic from fishing gear. The fishing gear plastic pollution might be targeted, and possibly less of a matter of scale and more about where it is dumped. Or not, youād have to have a model of ocean circulation, plastic breakdown, and dumping areas to make sense of that. It would help to know how much of the increase in plastic use is burned, landfilled, or dumped at sea in future.
Thereās some discussion about PFAS pollutants, but the fundamentals are about ecology. Are there some pollutants that, if dumped once, could kill most marine life? I believe so, but Iām avoiding research of that topic on purpose for now, first because its about how to poison the ocean, and second, because the lesser cases with the same outcome rely more on marine ecology knowledge, something Iām still lacking.
Regardless of initial pressures on marine life, pressure on human food systems will lead to overfishing, as fisheries suffer declines, fishing fleets will cheat the system, and deplete populations. Between by-catch and abandoned gear, the fishing industry alone could destroy marine ecosystems as human population goes up and as pressure to cheat quota systems, for lack of food or to meet rising demand, also goes up. Not only will that lead to long-term fishery declines and even species extinction, it will lead to increasing amounts of fish that do not meet health and safety standards ending up on peopleās plates, before the fish are gone entirely. This is a bit of a tangent, but is important enough to explore on its own.
Another tangent is what contribution the ocean actually makes as a carbon sink. Iāve seen estimates from 25% to 40% (and one scientist claiming 50%), and the relevance of those numbers is a bit different. For example, the 25% is a historical account over the last few hundred years, whereas the higher numbers could refer to current sink contributions, but I have to track the higher numbers down to research sources.
Does killing off larger organisms lead to collapse of specific plankton populations? Thatās the bottom line as far as loss of the biological pump. Iām still working on it, I donāt have much time, so give me a chance, Iāll try to finish links on this comment tonight, and maybe get a few into the prior comment.
This is really about ocean tipping points as well, another research topic. Yeah, I need time.
Finally, thereās the possibility that leaving the ocean and coastlines entirely alone while reducing GHG emissions could increase the action of the biological pump enough to draw down our current GHGās and reduce GAST overall. By leaving the ocean alone we could undo climate change. But that would mean doing everything right. Not the usual for us humans.
Oops, I though I had answered this commentāsorry about the delay.
Thanks for the links, this is interesting. I am not sure I will dig into this topic right now but I might at some point when looking into ecological collapse, so this might provide a good start.
I was aware of the huge impact of discarded fishing gear on plastic, but probably neglected other impacts you mentioned.
Well put, exactly the problem. Every time there is an issue, whether social or ecological, someone says āyeah but we can do that to solve the problemā. But we donāt. Thatās the issue.