5 ms·

Defining a discrete "boundary" seems misleading, since most of these things have linearly worse effects as you do more of them, there's no bright red sharp line

Defining a discrete "boundary" seems misleading, since most of these things have linearly worse effects as you do more of them, there's no bright red sharp line. Eg. climate change is obviously bad, but you can't really point to a specific temperature as a "boundary" - 2C of warming is worse than 1.5C, 3C is worse than 2C, 4C is worse than 3C, and so on. I didn't recognize the term "novel entities" - it seems to refer to new industrial chemicals, plastics, etc. developed by humans that don't exist in nature. The graphic is drawing on a paper which says people are developing and releasing these chemicals without enough safety testing. That's bad, sure. But how could you say when this has crossed a "boundary" - at a million tons of release? Ten million tons? Of which chemicals? Any chemicals? The paper is very fuzzy, and basically just waves its hands and says: "We define and apply three criteria for assessment of the suitability of control variables for the boundary: feasibility, relevance, and comprehensiveness. We propose several complementary control variables to capture the complexity of this boundary, while acknowledging major data limitations. We conclude that humanity is currently operating outside the planetary boundary based on the weight-of-evidence for several of these control variables." Again, sure, obviously pollution is bad, but this doesn't meaningfully define what a "boundary" would be, or what the consequences of crossing it are. https://pubs.acs.org/doi/10.1021/acs.est.1c04158# https://pubs.acs.org/doi/10.1021/acs.est.1c04158#

Bud 3y ago
Please cite support for your claim that effects of surpassing these boundaries are linear. The people who actually know the science in these areas do not agree with you. Specifically with regard to global warming, the science has been clear on this for decades now: past around 1.5C, we risk cascading effects that could be uncontrollable. This is really fairly common in natural systems: if you mess it up, past a certain boundary effects accelerate and are uncontrollable.
- bobjonesy 3y ago
  The science has been clear? Phrasing like "we risk" and "that could be" don't inspire clarity.
  - ClumsyPilot 3y ago
    Science if pretty clear that if you build a house out of flammable materials with no regard for fire safety, it could burn down and kill everyone kill it. What you are doing is the equivalent of complaining that your house didn’t burn down this month and therefore fire safety is fake science
  - mostlylurks 3y ago
    Non-discreteness does not imply linearity. Seems like a nitpicky point to make, but in fact the difference between linearity and other types of continuous growth can easily be the difference between a non-issue and an unprecedented catastrophe.
kelseyfrog 3y ago
They are identified as the largest contributing factors to Holocene maintence[1]. The thresholds are boundaries where long-term Holocene maintenance no longer holds. Just curious, is Holocene maintenance is important to you? 1. https://www.science.org/doi/10.1126/sciadv.adh2458 https://www.science.org/doi/10.1126/sciadv.adh2458
- thriftwy 3y ago
  Holocene is very important for countries with harge coastal cities, since these may submerge. Iran and North Korea would likely not care much.
  - JumpCrisscross 3y ago
    > Iran and North Korea would likely not care much "Iran is vulnerable to the arable land equipped for irrigation, food imports over total merchandise exports, and the cereal imports dependency ratio while being resilient per capita food production and food supply variability" [1]. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9874189/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9874189/
    - thriftwy 3y ago
      It is higly likely that end of Holocene will eventually make climate in Iran better in terms of arability.
      - kelseyfrog 3y ago
        Can you walk me through your argument? If it did, would you conclude that the negative outcomes experienced in other areas would be justifiable?
        thriftwy 3y ago
        Why would Iranians care abour other areas? When was the last time the rest of the world cared about them in a good way? Weather will become tropical all over planet, including Iran, which is likely too arid currently.
over_bridge 3y ago
Agreed. Setting a boundary invites people to point out that nothing happened the second that boundary was crossed. Maybe defining zones with consequences attached might be more meaningful so we can evaluate which cost is preferred - solving the problem or living with it.
- digging 3y ago
  > Setting a boundary invites people to point out that nothing happened the second that boundary was crossed. This problem is unsolvable by changing terminology because it's rooted in denial and misinformation. > Maybe defining zones with consequences attached might be more meaningful so we can evaluate which cost is preferred - solving the problem or living with it. How is this not identical to setting boundaries? A zone is a bounded area. As for the preferred cost - the only correct response is solving the problem. The alternative is not "live with it", it's failure and suffering. Only when we're in the failure state does the choice become "live with it [and suffer]" or "die". You seem to have internalized the suicidal narrative that addressing climate change is a tax on our economy, when in fact it's just a different and more productive way to spend money that we're already spending.
  - over_bridge 3y ago
    What are you on about? So condescending... I'm just saying that you can link certain zones to specific outcomes. If we move into a new zone we haven't crossed the boundary (which feels final and irreversible), we are in a new zone with new consequences. We can leave that zone as well and change the outcome. Obviously I'm in favour of fixing the problems but I'm not the majority of elected officials or their climate denying donors. You need to frame it in a way that they can act on it hence the choice.
abdullahkhalids 3y ago
I have not a climate expert but I can give the abstract math answer to what is a boundary. A dynamic system can have several stable states. There can exist forcing functions F_param, which can push the system towards different directions. Due to the interaction of the these pushes, the system can settle into a single stable state. Now, start changing one param, which only linearly changes one of the forcing function's direction. But eventually, the forcing function param will cross a value so that instead of the system accelerating towards the first stable state, the system starts accelerating towards another stable state. That crossover point for param is the boundary. In other words a linear small change in param can create a highly non-linear and large change in the state of the system. That is the intuition about keeping warming below 2C, for example. Once Delta T goes beyond 2C, the system starts rapidly accelerating towards a new stable state which is very bad for humans.
- retrac 3y ago
  There are examples at a smaller scale. Nutrient pollution (nitrogen, phosphorous fertilizer in water) can build up for quite a while in a lake with no apparent effect. For reasons not well understood, sometimes after quite a long time (many years) of rising nitrogen/phosphorous levels, run-away growth of algae occurs suddenly and rapidly, depleting the lake of oxygen and killing off most animals and plants. Lakes and ocean regions which have undergone this process thoroughly become stable in their own way, with anaerobic bacteria and algae, but no plants or fish: https://en.wikipedia.org/wiki/Dead_zone_(ecology) https://en.wikipedia.org/wiki/Dead_zone_(ecology)
- nostrademons 3y ago
  That's very helpful, thanks. It sounds like the implication is that the earth has already left the stable equilibrium of the holocene and has now entered chaotic-behavior territory. This squares with a lot of the other climate science I've read (eg. 1.5C being the boundary and us going past it, my wife's climate-change focused employer shifting the focus from mitigation to resilience, or just private chats with climate scientists where they admit that yes, we're past the point of no return) and geologists now saying we're in the anthropocene era. I'm not entirely sure I'd classify this as being "very bad for humans" though. It does mean that our assumptions about very basic things like "Can humans live in this part of earth?" may not be valid. But humanity (and life) in general has proven to be very resilient. It's probably bad news for a significant number of specific humans, and very bad news for the social systems that currently bind us, but it seems likely that some form of descendant from humanity will survive.
michaelbuckbee 3y ago
My understanding was that the "boundaries" marked the point where the normal stabilization mechanisms in the environment wouldn't bounce back or where they were so kicked over that change rapidly accelerated. It was explained to me like putting salt into a freshwater pond. It can take some but the salinity eventually reaches a point (boundary) where the fish die and you can't really "go back" and take out the salt.
abeppu 3y ago
Maybe the boundary isn't "discrete" or a "bright red sharp line". But for climate change, haven't relevant experts been saying for some time that effects _aren't_ linear because of feedback loops? If each of several such feedback mechanisms has a 'steep' region where small differences can be amplified, then there may be multiple 'soft' boundaries. I think the non-science part of this is we can't know with certainty where these feedback loops kick in until a while after we've already crossed them. But just b/c we can't know with certain where the boundaries are ahead of time doesn't mean it isn't really stupid to be cavalierly charging off into uncharted territory.
- mlyle 3y ago
  You may not know where the boundaries are exactly, but you can come up with bounds: lower bounds are places where Earth has spent a lot of time in the geological record in regimes that are compatible with human life; upper bounds where known terrible effects are guaranteed to happen.
  - abeppu 3y ago
    What's an example of a useful known upper bound where terrible effects are guaranteed but we haven't had to actually live through them? Naming that we don't know the specific values is important; given the stakes at play, the fact that we don't know where they are ought to push us to stay close to the lower bounds. If we want to discover where the boundaries are, we can, but only at great cost.
    - mlyle 3y ago
      E.g. a value of CO2 where by direct radiative forcing, without feedback, terrible stuff happens.
      - abeppu 3y ago
        Right, so for the purposes of predicting what will happen on our actual planet, on which our continued existence is dependent, this is a very loose upper bound right? I'm not claiming that knowledge of where the boundary values lie is somehow epistemically unavailable. But there's some important, lower, unknown value, beyond which a bunch of very bad stuff will already happen, and learning the exact values through experience is extremely costly. In the context of responding to this report which is saying "we have already crossed the boundaries! (and we should immediately try to course correct)" rather than squabbling about "well, do you really know the boundary on each of these factors", I think the more honest and pragmatic reframing is to say "we don't know where the boundaries are, but we're headed rapidly away from the known safe region, and we should turn back immediately."
deleted 3y ago
[deleted]
dylan604 3y ago
> But how could you say when this has crossed a "boundary" When you take samples of ocean water at various depths and locations and they all come back with having microplastics, you can go ahead and say we've crossed a boundary. When you have factories producing "forever" chemicals that have high concentrations feeding into water table and soil that can be detected large distances away from the source, you can consider a boundary crossed. You don't have to be obtuse about admitting we've fucked up, we continue to fuck up, and we are very hesitant to stop fucking up. To me, trying to put these definitions of what is a "boundary" seems rather small minded. We know we're causing things. We know we don't have to do these things, but we're lazy and comfortable with what these things allow us to do. Until we can fix human nature, I don't see us fixing mother nature.
- nullstyle 3y ago
  > We know we don't have to do these things, but we're lazy and comfortable with what these things allow us to do. That's absurdly reductive.
  - dylan604 3y ago
    Is it? The source for these things tends to be from the waste of the things society throws away after using once. If we weren't comfortable with it, we'd make changes to make the discomfort go away. If we feel some discomfort but choose to ignore it, we're lazy.
    - nullstyle 3y ago
      Yes, your opinion here is absurdly reductive. Open your eyes, my dude. Get out there and live a little; It shouldn't hard to see that the situation is more complex than "We're lazy sinners." Here's just one perspective on the complicated situation we find ourselves in: https://www.youtube.com/watch?v=OW8vkUY93i8 https://www.youtube.com/watch?v=OW8vkUY93i8. There are many perspectives on this _historic global issue_ if you are open to them.
      - 3y ago
LASR 3y ago
> 2C of warming is worse than 1.5C, 3C is worse than 2C, 4C is worse than 3C, and so on. Are you thinking about continous instead of linear? The effects of global temperature rise are certainly non-linear, given the extremely complex dynamical system under it.
- gowld 3y ago
  "monotonically"
jauntywundrkind 3y ago
I find it doesn't strain me at all to take these warning signs as is, without having to feel tied in a knot over what the word "boundary" means.
pjerem 3y ago
As far as I understand, there is not any boundary about climate change. +1.9 will be worse than +1.8 but better than 2.0 The more we wait, the harder the consequences but, for better or worse, there will never be a threshold where we will be in position to abandon the fight. Also the good news seems to be that there is in fact very few inertia in the climate system : every increase in temperature is forever but we will always have the choice between keeping the current situation (by acting drastically) or getting an even worse outcome (by doing nothing).
- nostrademons 3y ago
  My understanding is that that's technically true, but not what they mean here. The idea behind 1.5C is that that's (supposedly, and probably given what we've observed in 2022-2023) the point at which natural feedback loops kick in and climate change becomes non-linear. So for example, 1.3C is better than 1.4C is better than 1.5C. But if you cross 1.5C, you might get decreased albedo from glaciers melting, or increased methane emissions for permafrost. The result might be that you can't actually have a state with 1.8C in warming, because once you cross 1.5 you trigger natural feedback loops which bake in an extra 1C of warming. Total climate change jumps straight from 1.5C to 2.5C, because once you cross 1.5C it's not just us warming the planet anymore. It's still better to have 1.8C of emissions than 1.9C than 2.0, but the difference in actual temperatures might be 4.8C vs 4.9C vs 5.0, while if we could've just stayed under 1.5C we could've stayed under 1.5.
datadrivenangel 3y ago
You only need a tiny bit of nerve gas to kill an entire population. There's less certainty about what less obviously lethal interventions result in. CFCs deplete the ozone layer, which increases the amount of UVB light reaching the planet, which increases cancer rates, which reduces the lifespan of humans and many animals. We can model some of this even if there's uncertainty. Boundaries are harder to define, but models can identify some of them. If multiple climate models are more accurate on current data by predicting disastrous increases in ice melt and sea level rise somewhere above 6-8C we can probably draw a boundary.
dubcanada 3y ago
That's because it's supposed to be a doom article. Nobody has any idea, it's not something you can quantify (well you can, but if 99 of the 100 simulations say nothing and 1 says we all die, what does that mean?). And when it does happen it will largely be too late to do anything. Which is why we get doom articles like this. It's purpose is to attempt to get people to care. The earth could just fix itself. It is very capable of doing so, and has done so in the past. It may not be able to sustain us anymore, but life will live on in some form.

Bud 3y ago

Please cite support for your claim that effects of surpassing these boundaries are linear. The people who actually know the science in these areas do not agree with you. Specifically with regard to global warming, the science has been clear on this for decades now: past around 1.5C, we risk cascading effects that could be uncontrollable. This is really fairly common in natural systems: if you mess it up, past a certain boundary effects accelerate and are uncontrollable.

bobjonesy 3y ago
The science has been clear? Phrasing like "we risk" and "that could be" don't inspire clarity.
- ClumsyPilot 3y ago
  Science if pretty clear that if you build a house out of flammable materials with no regard for fire safety, it could burn down and kill everyone kill it. What you are doing is the equivalent of complaining that your house didn’t burn down this month and therefore fire safety is fake science
- mostlylurks 3y ago
  Non-discreteness does not imply linearity. Seems like a nitpicky point to make, but in fact the difference between linearity and other types of continuous growth can easily be the difference between a non-issue and an unprecedented catastrophe.

kelseyfrog 3y ago

They are identified as the largest contributing factors to Holocene maintence[1]. The thresholds are boundaries where long-term Holocene maintenance no longer holds. Just curious, is Holocene maintenance is important to you? 1. https://www.science.org/doi/10.1126/sciadv.adh2458 https://www.science.org/doi/10.1126/sciadv.adh2458

thriftwy 3y ago
Holocene is very important for countries with harge coastal cities, since these may submerge. Iran and North Korea would likely not care much.
- JumpCrisscross 3y ago
  > Iran and North Korea would likely not care much "Iran is vulnerable to the arable land equipped for irrigation, food imports over total merchandise exports, and the cereal imports dependency ratio while being resilient per capita food production and food supply variability" [1]. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9874189/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9874189/
  - thriftwy 3y ago
    It is higly likely that end of Holocene will eventually make climate in Iran better in terms of arability.
    - kelseyfrog 3y ago
      Can you walk me through your argument? If it did, would you conclude that the negative outcomes experienced in other areas would be justifiable?
      - thriftwy 3y ago
        Why would Iranians care abour other areas? When was the last time the rest of the world cared about them in a good way? Weather will become tropical all over planet, including Iran, which is likely too arid currently.

over_bridge 3y ago

Agreed. Setting a boundary invites people to point out that nothing happened the second that boundary was crossed. Maybe defining zones with consequences attached might be more meaningful so we can evaluate which cost is preferred - solving the problem or living with it.

digging 3y ago
> Setting a boundary invites people to point out that nothing happened the second that boundary was crossed. This problem is unsolvable by changing terminology because it's rooted in denial and misinformation. > Maybe defining zones with consequences attached might be more meaningful so we can evaluate which cost is preferred - solving the problem or living with it. How is this not identical to setting boundaries? A zone is a bounded area. As for the preferred cost - the only correct response is solving the problem. The alternative is not "live with it", it's failure and suffering. Only when we're in the failure state does the choice become "live with it [and suffer]" or "die". You seem to have internalized the suicidal narrative that addressing climate change is a tax on our economy, when in fact it's just a different and more productive way to spend money that we're already spending.
- over_bridge 3y ago
  What are you on about? So condescending... I'm just saying that you can link certain zones to specific outcomes. If we move into a new zone we haven't crossed the boundary (which feels final and irreversible), we are in a new zone with new consequences. We can leave that zone as well and change the outcome. Obviously I'm in favour of fixing the problems but I'm not the majority of elected officials or their climate denying donors. You need to frame it in a way that they can act on it hence the choice.

abdullahkhalids 3y ago

I have not a climate expert but I can give the abstract math answer to what is a boundary. A dynamic system can have several stable states. There can exist forcing functions F_param, which can push the system towards different directions. Due to the interaction of the these pushes, the system can settle into a single stable state. Now, start changing one param, which only linearly changes one of the forcing function's direction. But eventually, the forcing function param will cross a value so that instead of the system accelerating towards the first stable state, the system starts accelerating towards another stable state. That crossover point for param is the boundary. In other words a linear small change in param can create a highly non-linear and large change in the state of the system. That is the intuition about keeping warming below 2C, for example. Once Delta T goes beyond 2C, the system starts rapidly accelerating towards a new stable state which is very bad for humans.

retrac 3y ago
There are examples at a smaller scale. Nutrient pollution (nitrogen, phosphorous fertilizer in water) can build up for quite a while in a lake with no apparent effect. For reasons not well understood, sometimes after quite a long time (many years) of rising nitrogen/phosphorous levels, run-away growth of algae occurs suddenly and rapidly, depleting the lake of oxygen and killing off most animals and plants. Lakes and ocean regions which have undergone this process thoroughly become stable in their own way, with anaerobic bacteria and algae, but no plants or fish: https://en.wikipedia.org/wiki/Dead_zone_(ecology) https://en.wikipedia.org/wiki/Dead_zone_(ecology)
nostrademons 3y ago
That's very helpful, thanks. It sounds like the implication is that the earth has already left the stable equilibrium of the holocene and has now entered chaotic-behavior territory. This squares with a lot of the other climate science I've read (eg. 1.5C being the boundary and us going past it, my wife's climate-change focused employer shifting the focus from mitigation to resilience, or just private chats with climate scientists where they admit that yes, we're past the point of no return) and geologists now saying we're in the anthropocene era. I'm not entirely sure I'd classify this as being "very bad for humans" though. It does mean that our assumptions about very basic things like "Can humans live in this part of earth?" may not be valid. But humanity (and life) in general has proven to be very resilient. It's probably bad news for a significant number of specific humans, and very bad news for the social systems that currently bind us, but it seems likely that some form of descendant from humanity will survive.

michaelbuckbee 3y ago

My understanding was that the "boundaries" marked the point where the normal stabilization mechanisms in the environment wouldn't bounce back or where they were so kicked over that change rapidly accelerated. It was explained to me like putting salt into a freshwater pond. It can take some but the salinity eventually reaches a point (boundary) where the fish die and you can't really "go back" and take out the salt.

abeppu 3y ago

Maybe the boundary isn't "discrete" or a "bright red sharp line". But for climate change, haven't relevant experts been saying for some time that effects _aren't_ linear because of feedback loops? If each of several such feedback mechanisms has a 'steep' region where small differences can be amplified, then there may be multiple 'soft' boundaries. I think the non-science part of this is we can't know with certainty where these feedback loops kick in until a while after we've already crossed them. But just b/c we can't know with certain where the boundaries are ahead of time doesn't mean it isn't really stupid to be cavalierly charging off into uncharted territory.

mlyle 3y ago
You may not know where the boundaries are exactly, but you can come up with bounds: lower bounds are places where Earth has spent a lot of time in the geological record in regimes that are compatible with human life; upper bounds where known terrible effects are guaranteed to happen.
- abeppu 3y ago
  What's an example of a useful known upper bound where terrible effects are guaranteed but we haven't had to actually live through them? Naming that we don't know the specific values is important; given the stakes at play, the fact that we don't know where they are ought to push us to stay close to the lower bounds. If we want to discover where the boundaries are, we can, but only at great cost.
  - mlyle 3y ago
    E.g. a value of CO2 where by direct radiative forcing, without feedback, terrible stuff happens.
    - abeppu 3y ago
      Right, so for the purposes of predicting what will happen on our actual planet, on which our continued existence is dependent, this is a very loose upper bound right? I'm not claiming that knowledge of where the boundary values lie is somehow epistemically unavailable. But there's some important, lower, unknown value, beyond which a bunch of very bad stuff will already happen, and learning the exact values through experience is extremely costly. In the context of responding to this report which is saying "we have already crossed the boundaries! (and we should immediately try to course correct)" rather than squabbling about "well, do you really know the boundary on each of these factors", I think the more honest and pragmatic reframing is to say "we don't know where the boundaries are, but we're headed rapidly away from the known safe region, and we should turn back immediately."

deleted 3y ago

[deleted]

dylan604 3y ago

> But how could you say when this has crossed a "boundary" When you take samples of ocean water at various depths and locations and they all come back with having microplastics, you can go ahead and say we've crossed a boundary. When you have factories producing "forever" chemicals that have high concentrations feeding into water table and soil that can be detected large distances away from the source, you can consider a boundary crossed. You don't have to be obtuse about admitting we've fucked up, we continue to fuck up, and we are very hesitant to stop fucking up. To me, trying to put these definitions of what is a "boundary" seems rather small minded. We know we're causing things. We know we don't have to do these things, but we're lazy and comfortable with what these things allow us to do. Until we can fix human nature, I don't see us fixing mother nature.

nullstyle 3y ago
> We know we don't have to do these things, but we're lazy and comfortable with what these things allow us to do. That's absurdly reductive.
- dylan604 3y ago
  Is it? The source for these things tends to be from the waste of the things society throws away after using once. If we weren't comfortable with it, we'd make changes to make the discomfort go away. If we feel some discomfort but choose to ignore it, we're lazy.
  - nullstyle 3y ago
    Yes, your opinion here is absurdly reductive. Open your eyes, my dude. Get out there and live a little; It shouldn't hard to see that the situation is more complex than "We're lazy sinners." Here's just one perspective on the complicated situation we find ourselves in: https://www.youtube.com/watch?v=OW8vkUY93i8 https://www.youtube.com/watch?v=OW8vkUY93i8. There are many perspectives on this _historic global issue_ if you are open to them.
    - 3y ago

LASR 3y ago

> 2C of warming is worse than 1.5C, 3C is worse than 2C, 4C is worse than 3C, and so on. Are you thinking about continous instead of linear? The effects of global temperature rise are certainly non-linear, given the extremely complex dynamical system under it.

gowld 3y ago
"monotonically"

jauntywundrkind 3y ago

I find it doesn't strain me at all to take these warning signs as is, without having to feel tied in a knot over what the word "boundary" means.

pjerem 3y ago

As far as I understand, there is not any boundary about climate change. +1.9 will be worse than +1.8 but better than 2.0 The more we wait, the harder the consequences but, for better or worse, there will never be a threshold where we will be in position to abandon the fight. Also the good news seems to be that there is in fact very few inertia in the climate system : every increase in temperature is forever but we will always have the choice between keeping the current situation (by acting drastically) or getting an even worse outcome (by doing nothing).

nostrademons 3y ago
My understanding is that that's technically true, but not what they mean here. The idea behind 1.5C is that that's (supposedly, and probably given what we've observed in 2022-2023) the point at which natural feedback loops kick in and climate change becomes non-linear. So for example, 1.3C is better than 1.4C is better than 1.5C. But if you cross 1.5C, you might get decreased albedo from glaciers melting, or increased methane emissions for permafrost. The result might be that you can't actually have a state with 1.8C in warming, because once you cross 1.5 you trigger natural feedback loops which bake in an extra 1C of warming. Total climate change jumps straight from 1.5C to 2.5C, because once you cross 1.5C it's not just us warming the planet anymore. It's still better to have 1.8C of emissions than 1.9C than 2.0, but the difference in actual temperatures might be 4.8C vs 4.9C vs 5.0, while if we could've just stayed under 1.5C we could've stayed under 1.5.

datadrivenangel 3y ago

You only need a tiny bit of nerve gas to kill an entire population. There's less certainty about what less obviously lethal interventions result in. CFCs deplete the ozone layer, which increases the amount of UVB light reaching the planet, which increases cancer rates, which reduces the lifespan of humans and many animals. We can model some of this even if there's uncertainty. Boundaries are harder to define, but models can identify some of them. If multiple climate models are more accurate on current data by predicting disastrous increases in ice melt and sea level rise somewhere above 6-8C we can probably draw a boundary.

dubcanada 3y ago

That's because it's supposed to be a doom article. Nobody has any idea, it's not something you can quantify (well you can, but if 99 of the 100 simulations say nothing and 1 says we all die, what does that mean?). And when it does happen it will largely be too late to do anything. Which is why we get doom articles like this. It's purpose is to attempt to get people to care. The earth could just fix itself. It is very capable of doing so, and has done so in the past. It may not be able to sustain us anymore, but life will live on in some form.