[HN Gopher] Probability Estimates of a 21st Century AMOC Collapse
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Probability Estimates of a 21st Century AMOC Collapse
Author : rntn
Score : 67 points
Date : 2024-08-03 17:39 UTC (5 hours ago)
(HTM) web link (arxiv.org)
(TXT) w3m dump (arxiv.org)
| dayofthedaleks wrote:
| I appreciate an abstract that doesn't beat about the bush:
|
| The collapse time is estimated between 2037-2064 (10-90% CI) with
| a mean of 2050 and the probability of an AMOC collapse before the
| year 2050 is estimated to be 59 +/- 17%.
|
| We'll miss you, Gulf Stream.
| roughly wrote:
| We really, really will.
| bendigedig wrote:
| The AMOC and the Gulf Stream are two separate systems.
| cube2222 wrote:
| For those curious, I found this article[0] going into the
| details, differences, and interactions between them.
|
| TLDR: the Gulf Stream originates from a very different
| phenomenon than the AMOC and is not at risk of collapse. A
| small part of the heat transported by the Gulf Stream does
| originate from the AMOC though, but its collapse would be
| much less severe than a full collapse of the Gulf Stream.
|
| [0]: https://bigthink.com/strange-maps/gulf-stream-collapse-
| amoc/
| candiddevmike wrote:
| Wonder how much immigration this will create from northern
| Europe. AIUI the collapse will make those countries quite
| chilly.
| huuhee3 wrote:
| I wonder how the summers would be under this scenario. Cold
| winters alone wouldn't be such a huge problem, but if food
| production collapses then we'll be in trouble.
| lkrubner wrote:
| I worry that these scientists are focused on the 21st Century
| simply because many people will only care about this if it
| happens during our lifetimes. But if we care about our great-
| grandchildren, we should also be worried about the 22nd Century,
| and the possibility that the Gulf Stream will collapse before the
| year 2200 is great.
| ben_w wrote:
| Predicting things that far ahead is almost impossible.
|
| Looking back, the greenhouse effect of CO2 was known in the
| 1800s, but even at the end of that century people thought it
| would take a millennium and be good.
|
| Looking forward, it's _technically possible_ (yes I have done
| the maths) to build a global power grid today such that the
| Scaninavian arctic midwinter can be powered by solar panels in
| New Zealand, but only China makes enough aluminium and only
| China has demonstrated any interest in attempting massive
| infrastructure projects of this kind for soft power projection.
|
| When do we get von Neumann replicators? Do we make GM algae
| that turn atmospheric CO2 directly into crude oil to substitute
| fossil oil in the petrochemical industry? Will fundamentalists
| Hindus create a synthetic disease that induces an allergy to
| beef thus causing an end to cattle farming? Will the Russian
| invasion of Ukraine escalate into WW3?
|
| I can't tell which specific big things will radically change
| the world, but I am sure there's going to be at least one every
| 25 years -- one between today and 2050, at least two more by
| 2100, and at least four between 2100 and 2200.
| IIAOPSW wrote:
| >Looking back, the greenhouse effect of CO2 was known in the
| 1800s, but even at the end of that century people thought it
| would take a millennium and be good.
|
| IIRC Charles Babbage wrote in his survey of British Industry
| for the royal society words to the effect of "it is not
| presently known how exactly the coal exhaust is recycled back
| into the ground".
|
| Maybe some people correctly guessed that it wasn't recycled
| at all and in fact is an expendable (albeit quite large)
| resource, but their guess was as good as any other and far
| from something that was widely _known_ and believed.
| ben_w wrote:
| By "the end of that century" I mean 1896 and Svante
| Arrhenius, which was a bit after Babbage died (1871).
|
| Arrhenius published an update in 1908 (not sure when he
| realised the mistake) accounting for the increased rate of
| CO2 emissions, stating that would be "beneficial"[0] in his
| own lifetime -- he ended up dying in 1927, I'll let others
| decide if it was a net good or bad by that point.
|
| [0] Wikipedia's citation for this is "Arrhenius, S., Worlds
| in the Making: The Evolution of the Universe. New York,
| Harper & Row, 1908," -- https://dn790004.ca.archive.org/0/i
| tems/worldsinmakingev00ar...
|
| I can find the "beneficial" part, but not (yet) the "in
| [his] lifetime" part. Quoting from the linked archive copy:
|
| "By the influence of the increasing percentage of carbonic
| acid in the atmosphere, we may hope to enjoy ages with more
| equable and better climates, especially as regards the
| colder regions of the earth, ages when the earth will bring
| forth much more abundant crops than at present, for the
| benefit of rapidly propagating mankind." - page 63.
| candiddevmike wrote:
| > I can't tell which specific big things will radically
| change the world, but I am sure there's going to be at least
| one every 25 years -- one between today and 2050
|
| Aren't we still due for one between now and 2025 then?
| ben_w wrote:
| We've had several.
|
| The first draft of the Human Genome Project was only
| published in 2003, but that covered 92% of the genome; it
| only got up to 99.7% in 2022. Personal genome tests are now
| regularly on special offer for a few hundred bucks rather
| than the $2.7 billion (non-inflation adjusted) of the
| original Human Genome Project.
|
| Genetic engineering was possible in 1999, but it wasn't
| until 2005 that CRISPR was discovered, 2006 that it was
| theorised how it might function, 2007 that this was
| demonstrated, 2012 until it was patented, and 2013 until it
| became commercially viable.
|
| Mobiles and the web technically existed in 1999, but the
| former were mostly black and white screens with number-pad
| keyboards and the latter was mostly dialup; now it's good
| enough that the _global pandemic we just went through_ had
| a lot of people switch to remote work -- and ask to keep
| doing that after the pandemic restrictions ended. The tech
| that enabled the vaccines to be created so fast, or even
| their genomes to be sequenced so fast, didn 't exist in
| 1999.
|
| PV existed in 1999, but there was a total installed
| nameplate capacity of 0.8 GW; in 2022 that was 1061.7 GW,
| with an estimated 341-402 GW in 2023 and 600-660 GW this
| year, likely taking the nameplate capacity over the current
| total global electricity demand. (The capacity factor was
| 14% in 2022, so there's room for the nameplate capacity to
| become 700% of current global electrical demand).
|
| 3D printers existed in 1999, but cheap domestic models only
| happened around the time of RepRap in 2005. Brief period
| where it seemed everyone was worried about domestic
| printers making guns, now industrial printers make
| spaceship engines.
|
| AI has gone from "squiggly line under a mis-spelled word",
| Norns with tiny neural nets, and the state machines of
| video game NPCs, to what is essentially the character of
| the main computer on TNG era Star Trek, complete with
| universal translator, creating interactive NPCs and
| environments on the fly, and letting us talk to an always-
| listening microphone when we want to change which music is
| playing or what mood we want the lights to provide.
|
| China has gone from "LOL" to "superpower". North Korea got
| nukes (and if they can do it, anywhere bigger than a tiny
| island or a city-state can do it). Pakistan, which has
| nukes, had a military coup in 1999; 9/11 was a pretty big
| event that shifted American international behaviour, but
| the choices the US government made in Iraq and Afghanistan
| were sufficiently tone-deaf to the locals it likely played
| a significant role in the rise of ISIS.
| actionfromafar wrote:
| Re the last sentence, quite an understatement.
| sillywalk wrote:
| From a news article[0] that links to the paper:
|
| " "All the negative side effects of anthropogenic climate change,
| they will still continue to go on, like more heat waves, more
| droughts, more flooding," he told CNN. "Then if you also have on
| top of that an AMOC collapse ... the climate will become even
| more distorted."
|
| ...
|
| The impacts of an AMOC collapse would leave parts of the world
| unrecognizable.
|
| In the decades after a collapse, Arctic ice would start creeping
| south, and after 100 years, would extend all the way down to the
| southern coast of England. Europe's average temperature would
| plunge, as would North America's - including parts of the US. The
| Amazon rainforest would see a complete reversal in its seasons;
| the current dry season would become the rainy months, and vice
| versa. "
|
| [0] https://lite.cnn.com/2024/08/02/climate/atlantic-
| circulation...
| warkdarrior wrote:
| Nice, so that's how we counteract climate change!
| Ar-Curunir wrote:
| That is climate change...
| actionfromafar wrote:
| I'm sure the US and EU would not do _anything_ crazy if its
| crops started failing.
| CalRobert wrote:
| This seems like it should be the front page story on every news
| outlet. "Your kids will live in a frozen wasteland and perhaps
| die of starvation or conflict by middle age" is a big deal, is it
| not? It is to me.
| ben_w wrote:
| It's more like "Europe north of about Paris will look like
| southern Canada already does", which is bad but not necessarily
| catastrophic.
|
| (Unless this leads to a war, which it might).
| Ekaros wrote:
| Hmm, so obviously we have to compensate with even more CO2
| and other greenhouse gasses. It is not unreasonable solution
| for those living the area.
| ben_w wrote:
| The people living in the entirety of Europe combined are
| outnumbered by a factor of 10 by people who very much won't
| let them. :P
| RandomLensman wrote:
| How?
| ben_w wrote:
| The usual methods. Not selling them stuff to burn,
| followed by military involvement if they try to
| manufacture super-greenhouse gases.
|
| Bear in mind that Europe trying to compensate for an AMOC
| collapse with more greenhouse gases would involve enough
| greenhouse gases to make India uninhabitable and that
| India has nukes, and that such a temperature change would
| significantly alter the agricultural productivity of the
| USA and the USA has nukes, and that half of China is a
| desert and China has nukes.
|
| I'm not sure if that kind of change would require global
| changes sufficient to melt the Greenland and Antarctic
| ice sheets, but if it did then that would also result in
| basically every costal nation also considering it an
| existential threat and thus warranting military action to
| prevent, _including the UK_.
| bendigedig wrote:
| Fuuuuuuuuuuck
| hyperpape wrote:
| Can anyone comment as to how seriously to take this paper? One
| paper is ultimately just one paper.
|
| The Wikipedia page on the AMOC
| (https://en.wikipedia.org/wiki/Atlantic_meridional_overturnin...)
| links to a page summarizing some scientists' reactions:
|
| https://www.sciencemediacentre.org/expert-reaction-to-paper-...
|
| However, I have no idea if this is representative or not.
| netsharc wrote:
| Those reactions are to the paper by 2 Danes, as covered in this
| article:
|
| https://www.wired.com/story/amoc-collapse-atlantic-ocean/
|
| HN discussion: https://news.ycombinator.com/item?id=41087977
| yodon wrote:
| There are about 20 major climate simulation models focused on
| ocean calculations at different research labs around the world.
|
| All of those models show the AMOC to be meta-stable (meaning it
| rapidly flips from on to off, as opposed to long gradual
| slowing).
|
| All of those models show the AMOC is on track to shut off
| "soon."
|
| All of those models show an AMOC shutoff event to be very
| serious, particularly for Northern Europe, but also for the
| world as a whole.
|
| Prior to this paper, the estimates on what "soon" meant were
| not very good and generally took the form of "it could be this
| century, or it could be in the next couple centuries."
|
| This paper has not been through peer review yet, but the
| authors are significant participants in the field.
|
| The paper is trying to answer one of the most important
| question in science right now, which is how long until the AMOC
| shuts down and what signals should one watch for to improve
| that prediction.
| truculent wrote:
| > All of those models show the AMOC is on track to shut off
| "soon."
|
| Presumably this means the AMOC is on track to hit its tipping
| point "soon". How long after hitting the tipping point would
| it take to "stop"? 100 years? Less?
| bikenaga wrote:
| For another point of view, see: "Uncertainties too large to
| predict tipping times of major Earth system components from
| historical data" -
| https://www.science.org/doi/10.1126/sciadv.adl4841
|
| Their primary example is the AMOC.
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