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.
(Unless this leads to a war, which it might).
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.
The scenario of "post AMOC collapse Europe tries to compensate with more global climate change" is an existential threat to at least some other nations, how many depends on the scale of the change caused by the AMOC collapse and thus the scale of the change from the super-greenhouse-gasses produced in this scenario to compensate for it; even if the UK/France nuclear arsenals were significantly larger, this would not be sufficient to deter India from using nukes in this scenario if conventional methods failed.
Also, again, deliberately trying to push through an AMOC with even more greenhouse gasses is something most people don't model, so all parties would have to seriously consider if this would be at the level to melt global ice-sheets causing a (58m Antarctica + 7m Greenland =) 65m sea level rise rather than the much smaller one we'd expect in a business-as-usual scenario.
Set this map to 65m: https://www.floodmap.net
Then consider each scenario. If the AMOC fails, it's an open question how severe that even is — I've seen estimates between 2°C and 30°C of local cooling, and I expect the lower range of that hence my previous statement "Europe north of about Paris will look like southern Canada already does".
At lower levels of that range, Europe just goes back to where we were a century ago, at higher levels it could only be "solved" by greenhouse gas emissions that would cause the Antarctic and Greenland ice sheets to fully melt. Looking at the global map, my guess is that Spain and France end up like the USA Pacific coast, which isn't too bad, while the UK and Ireland have severe issues.
But even a "mere" extra 2°C globally is enough to be an existential threat to certain populations including in parts of India, who would do whatever it takes to prevent that.
If it's really a 30°C collapse — and it would have to be on that scale to seriously consider global geo-engineering rather than retrofitting buildings and building greenhouses over the farmland — then that risks the aforementioned ice sheet collapse, which neither the UK nor Ireland can risk because that would turn the problem from "it's cold and we need to import food" to "and now 50% of the country is underwater", likewise half of Belgium, all of the Netherlands, much of Denmark, and a significant part of the most densely populated regions across the continent including Italy.
France, the only other nuclear armed state in the EU besides the UK, is only affected a little bit by the sea level rise, and thus the only one which might consider that course of action. But even they would have a serious engineering project to stop the Seine from flooding back to Paris. And even with that, silver bullets (your nukes) can't stop golden guns (other people's nukes).
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No, if this particular disaster happened we might try to mass-migrate to Africa (to a chorus of "oh no not again" from the destination), but I don't see our governments trying to solve it in the "old lady who swallowed a fly" approach.
Anyway, given that Europe is in some scenarios heating up a lot while in others (like here) it freezes - not sure any deserve much effort on speculation. Too much uncertainty.
I could believe anything from half of us being dead from an accidentally mis-engineered industrial GM algae, to von Neumann probes having been let loose on the moon for mass production of aluminium sheets to be placed in Earth-Sun L1 as a solar shade, to the escalation of current conflicts into WW3, to a random terrorist getting one nuke and missile and using that to trigger a continental-scale EMP that shuts down industrial civilisation in a densely populated area.
(Only things I won't believe involve large-scale cooperation, so we're not all going to speak Esperanto by then :P)
What is [Country X] currently doing about it, then? I'd assume Country X is currently banning/disincentivizing cars, cement, AI clusters, plane travel, and all kinds of much easier measures than literal nuclear attacks on other nuclear-equipped countries.
The world is complex. There are very few (maybe zero?) cases where any given nation state is willing to do "whatever it takes" to do anything.
> What is [Country X] currently doing about it, then? I'd assume Country X is currently banning/disincentivizing cars, cement, AI clusters, plane travel, and all kinds of much easier measures than literal nuclear attacks on other nuclear-equipped countries.
Country X in this case being India, here's what they're currently up to: https://www.weforum.org/agenda/2024/02/climate-policy-india/
I was wondering if I'd emphasised strongly enough "in the scenario where AMOC has collapsed and Europe tries to resolve this by overcoming it with extra greenhouse gas emissions". This scenario is trying to correct a local 2°C reduction with enough extra greenhouse gas for a global 2°C *more than today*. Current temperatures are about 1.25°C over the pre-industrial average, so that brings us to a minimum lower bound of 3.25°C over the pre-industrial average. This is in the region of "about half the world population experiences deadly humid heatwaves every year, the Himalayan glaciers stop supplying fresh water to half of the Indian population, marine ecosystems collapse, nearly all crops are negatively affected and yields fall rapidly, 18% loss of global GDP": https://unclimatesummit.org/comparing-climate-impacts-at-1-5....
We're not currently on a course for that in the first place, the current policies reach 2.6°C relative to the pre-industrial average (1.35°C relative to today) by 2100, so what India (and everyone else) has to do to prevent that is… basically what everyone is already currently doing. Though we can do better, and we should, because 2.6°C over pre-industrial (1.35°C over today) is still pretty bad.
But if it came to that scenario? That hypothetical where the European continent (including the UK) gives the world a two fingered salute? The negative consequences of being on the receiving end of the UK and France nuclear arsenals, would still be less bad for India and its people even if they acted unilaterally than allowing the extra impact of that much additional greenhouse gasses. Never mind that all those problems with an additional 2°C beyond current would cause to everyone else which means that the USA won't be on Europe's side if Europe was hubristic enough to try to solve this with geo-engineering rather than something less drastic.
And I did also only say that as a follow-on if "Not selling them stuff to burn" was shown to be insufficient. There are of course many stops between "don't sell them stuff" and "nuke them", I didn't feel it was a good use of time to enumerate them.
So, my bet is that in case of AMOC collapse Europeans simply elect authoritarian governments that will make some unfortunate developing countries colonies once again, and use them for farming. Given bad enough existential threat, things like rules-based order, human rights and democracy cease to matter, and the strong take what they want from the weaker parties. That's just how humans work.
I've seen estimates between 2°C and 30°C of local cooling.
I expect the lower range of that hence my previous statement "Europe north of about Paris will look like southern Canada already does", and that's fine for northern Europe but may still bite Spain (the Florida of Europe) as it (or at least its Med coast) is destined for being too hot more than being too cold.
Agriculture is the main thing, and I don't feel confident about predicting that, might be OK or not.
30°C of local cooling (I have no idea how that might even be possible but I've seen it as the worst case estimate) is way outside what most of the buildings are designed for.
And geoengineering to spew more CO2 into the atmosphere won't really work and is idiotic enough, it won't happen. I guess I didn't understand that line of argument because of how ridiculous it is.
Much more likely that Europe just switches to energy-intensive hydroponic farming and to imports for whatever that doesn't work for.
On this we both agree :)
> it won't happen
Sadly this doesn't follow from the premise; governments regularly do stupid things that don't work.