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A forthcoming collapse of the Atlantic meridional overturning circulation

nature.com

71–80 of 324 posts

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#71
post #38
post #11

Anyone else think that all these predictions are going to happen sooner rather than later in terms of the given prediction range? I can't help but think that a study focussing on a specific area like this one, antarctic sea ice, wildfire predictions etc must only be able to take so many variables into account and that second order effects, third order, fourth order and beyond from other climate subsystems are going t…

> compound and significantly accelerate the timeline There's a misconception that the biosphere is a delicate machine that will have a catastrophic internal failure if we don't follow the maintenance bibl^H^H^H^Hmanual, which apparently some experts have access to. In reality, it is a highly dynamic, self-repairing living organism, which we are a part of. There are at least as many negative feedback loops as positive…

What would be examples of negative feedback loops of comparable size?

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#72
post #65

Earlier quoted context omitted.

Yes the timeline for complete shift is before 2030. NYC weather is already temporarily altered each spring snd early summer with all the cold water from the Greenland melt, and that is just a slight shift away from there in the Gulf stream. When these shifts happen it's in about a dozen years. The last 8 years are the hottest in at least 150 years.

Are we expecting colder, or warmer weather in NY and New England from this? It's not clear to me from reading some of these articles. The expected effect for Northern Europe—that I understand.

Haven't you seen "The Day After Tomorrow"?

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#73
post #5
post #4

Last sentence in the Abstract: "We estimate a collapse of the AMOC to occur around mid-century under the current scenario of future emissions."

Further in the paper "The mean of the bootstrapped estimates of the tipping time is 〈tc〉 = 2050, and the 95% confidence interval is 2025–2095."

Climate change was sometimes dismissed (or reduced) by saying that’s it an issue for our grandchildren. With those error bars (NOW to +40 years), the immediate nature of the problem and the required response should hit home. Given recent heatwaves, I think nature is starting to hit us with the clue stick. I hope the important people are listening.

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#74

I've got a background in this field and I am very surprised to see this published in Nature. The model presented is purely statistical with no representation of the underlying physics. When we are dealing with a phenomenon that is driven by well-understood physical laws (e.g. geophysical fluid dynamics, radiation physics etc) then these physical models are the most reliable basis for prediction. When I say physical m…

The publication is in Nature Communications , which is a bit of a different (lesser) beast than Nature .

Thanks for pointing this out, I missed that

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#75
post #11

Anyone else think that all these predictions are going to happen sooner rather than later in terms of the given prediction range? I can't help but think that a study focussing on a specific area like this one, antarctic sea ice, wildfire predictions etc must only be able to take so many variables into account and that second order effects, third order, fourth order and beyond from other climate subsystems are going t…

There are so many tipping points and cascading effects at work that I doubt we have any real understanding of everything that is happening at the macroscopic level, nor even if we did could we battle everything everywhere all at once. I suspect whole swaths of humanity are in for perilous times ahead as the speed of the variances will outpace our collective ability to adapt. As the wizened Tool once sang[0], "Learn to swim, see you down in Arizona Bay".

[0]https://www.youtube.com/watch?v=CehYA3omb5o

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#77

Earlier quoted context omitted.

How does that 5C drop interact with the rise that we're currently concerned about? (Heatwave, wildfires in the med etc). I'm guessing it's hopelessly naive to assume it'll just... kinda cancel each other out?

The net energy of the system will remain the same, just distributed somewhere else.

the net energy of the system will not remain the same if we keep inputing at a non negatable rate

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#78
post #38
post #11

Anyone else think that all these predictions are going to happen sooner rather than later in terms of the given prediction range? I can't help but think that a study focussing on a specific area like this one, antarctic sea ice, wildfire predictions etc must only be able to take so many variables into account and that second order effects, third order, fourth order and beyond from other climate subsystems are going t…

> compound and significantly accelerate the timeline There's a misconception that the biosphere is a delicate machine that will have a catastrophic internal failure if we don't follow the maintenance bibl^H^H^H^Hmanual, which apparently some experts have access to. In reality, it is a highly dynamic, self-repairing living organism, which we are a part of. There are at least as many negative feedback loops as positive…

> it is a highly dynamic, self-repairing living organism

Organisms are self-repairing (to a certain extent) because they evolved to be so due to natural selection. The Earth as a whole and its climate are not subject to evolutionary pressure (they don’t reproduce) and thus are nothing like that.

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#79

I've got a background in this field and I am very surprised to see this published in Nature. The model presented is purely statistical with no representation of the underlying physics. When we are dealing with a phenomenon that is driven by well-understood physical laws (e.g. geophysical fluid dynamics, radiation physics etc) then these physical models are the most reliable basis for prediction. When I say physical m…

We've been very surprised as to which studies made it to nature over the past decade. I can't help but conclude that the influence of (politial) bias has been steadily growing over the years. (Fwiw, i'm personally taking the climate change subject extremely serious).

> Fwiw, i'm personally taking the climate change subject extremely serious

It's not worth anything, since the conservative rear guard and even outright deniers say the same thing these days. If you mean to separate yourself from such people, you'll have to put it differently.

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#80
post #57

This has been on my mind this past week(and is only lightly tangential)...but would we be able to observe adaptations being made by plants/animals/ecosystems on a timescale of years or decades...to the changing climate? Humans will be playing mental gymnastics and politics for quite a while before any true changes to move the needle are made...but all other biological things can just make the adaptations...given enou…

> but all other biological things can just make the adaptations

That only works with enough time, and changes are happening too quickly. Here's how animals have been adapting in just the last 50 years: https://phys.org/news/2022-10-wildlife-populations-plunge-ww...

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