Scrutable

Melting Antarctic ice will raise sea level by 2.5 metres – even if Paris climate goals are met, study finds

Melting of the Antarctic ice sheet will cause sea level rises of about two and a half metres around the world, even if the goals of the Paris agreement are met, research has shown.

The melting is likely to take place over a long period, beyond the end of this century, but is almost certain to be irreversible, because of the way in which the ice cap is likely to melt, the new model reveals.

Even if temperatures were to fall again after rising by 2C (3.6F), the temperature limit set out in the Paris agreement, the ice would not regrow to its initial state, because of self-reinforcing mechanisms that destabilise the ice, according to the paper published in the journal Nature.

That's a big if in the first sentence, as well - we're currently on track for about 3°C.

Quite a lot of the world's biggest and most 'important' cities are under 2.5 m above sea level. London, New York, Hong Kong, Shanghai, Rio de Janeiro, not to mention entire countries like the Maldives.

The Antarctic ice sheet has existed in roughly its current form for about 34m years, but its future form will be decided in our lifetimes, according to Levermann. “We will be renowned in future as the people who flooded New York City,” he told the Guardian.

Temperatures of more than 20C were recorded for the first time in the Antarctic earlier this year.

Obviously in addition to the increase in mean sea level, with extra water in the system high tides tend to get even higher, increasing the risk from extreme events. The UK is currently spending billions upgrading coastal flood defences to cope with 0.5 m of sea level rise, and even then are having to make a "managed retreat" from large areas of low-lying coastal land (this is code for allowing it to flood sacrificially, protecting adjacent areas with more economic value).

So we're not engineering our way out of it.

It would be entirely doable to limit carbon emissions and thus climate change to lower levels, and thus reduce the amount of locked-in melting. But we'd have to accept expense and inconvenience immediately, rather than drawn out over several centuries.

Presumably that's why most of the people striking for climate action are kids, and most of the people tutting about it are older folks who'll be safely dead so would rather not sacrifice anything for a collective effort.

The Netherlands are f.cked, and so are Bangladesh and Denmark.

Woodchopper wrote: ↑

Fri Sep 25, 2020 8:39 pm

The Netherlands are f.cked, and so are Bangladesh and Denmark.

Quite a few nuclear power stations around the world are built on the coast too.

More generally, loads of coastal areas have been used for landfill, military and fuel dumps, etc. So there's lots of extra pollution to leach out into the coastal shallows of Hampstead-super-Mare.

Still, much of Lincolnshire will disappear, so there is that.

El Pollo Diablo wrote: ↑

Sat Sep 26, 2020 5:42 am

Still, much of Lincolnshire will disappear, so there is that.

Flooding Lincolnshire would ironically be one of the best things we could do to stop, erm, places like Lincolnshire from flooding, because it would stop the degredation of huge amounts of peat and would create a massive new carbon sink in the form of rewilding.

We'd have to cut down on meat though.

Bird on a Fire wrote: ↑

Fri Sep 25, 2020 11:34 pm

More generally, loads of coastal areas have been used for landfill, military and fuel dumps, etc. So there's lots of extra pollution to leach out into the coastal shallows of Hampstead-super-Mare.

I’ve been looking at the flood map. https://www.floodmap.net/

With three meters (it doesn’t seem to like decimals) Cambridge, Dagenham and Doncaster are all near the sea shore.

Woodchopper wrote: ↑

Sun Sep 27, 2020 4:50 am

Bird on a Fire wrote: ↑

Fri Sep 25, 2020 11:34 pm

More generally, loads of coastal areas have been used for landfill, military and fuel dumps, etc. So there's lots of extra pollution to leach out into the coastal shallows of Hampstead-super-Mare.

I’ve been looking at the flood map. https://www.floodmap.net/

With three meters (it doesn’t seem to like decimals) Cambridge, Dagenham and Doncaster are all near the sea shore.

Wowzers. The isle of Ely will actually become a bonafide island.

El Pollo Diablo wrote: ↑

Sat Sep 26, 2020 5:42 am

Still, much of Lincolnshire will disappear, so there is that.

Some of Lincolnshire has already been disappeared - e.g. southern edge of Humber had defences breeches to make it salt marsh with bird reserves.

There's a preprepared plan for which other bits are to be surrendered.

AMS wrote: ↑

Fri Sep 25, 2020 9:14 pm

Woodchopper wrote: ↑

Fri Sep 25, 2020 8:39 pm

The Netherlands are f.cked, and so are Bangladesh and Denmark.

Quite a few nuclear power stations around the world are built on the coast too.

You probably don't need to worry about them. I couldn't find a timescale in the Nature article (may have been one but I'm not an expert reader). But based upon the IPCC report (pp. 205-207 and 270-271) 2.5 meters of sea level rise will take hundreds of years. So the coastal nuclear power plants will have been decommissioned long before then.

As stated by Bird, what is striking about the Nature article is that some of the ice melt will be irreversible. Even if in the future people manage to cool the world much of the ice isn't going to return.

Woodchopper wrote: ↑

Sun Sep 27, 2020 10:45 am

AMS wrote: ↑

Fri Sep 25, 2020 9:14 pm

Woodchopper wrote: ↑

Fri Sep 25, 2020 8:39 pm

The Netherlands are f.cked, and so are Bangladesh and Denmark.

Quite a few nuclear power stations around the world are built on the coast too.

You probably don't need to worry about them. I couldn't find a timescale in the Nature article (may have been one but I'm not an expert reader). But based upon the IPCC report (pp. 205-207 and 270-271) 2.5 meters of sea level rise will take hundreds of years. So the coastal nuclear power plants will have been decommissioned long before then.

You may have to look carefully at what "decommissioned" means locally. I'm not sure that all these sites are owned and regulated such that it doesn't result in some of them being only partially dismantled and then ignored.

And places like Dounraey aren't decommissioned yet, and keep getting handed between different organizations for decommissioning to happen.

dyqik wrote: ↑

Sun Sep 27, 2020 11:28 am

Woodchopper wrote: ↑

Sun Sep 27, 2020 10:45 am

AMS wrote: ↑

Fri Sep 25, 2020 9:14 pm

Quite a few nuclear power stations around the world are built on the coast too.

You probably don't need to worry about them. I couldn't find a timescale in the Nature article (may have been one but I'm not an expert reader). But based upon the IPCC report (pp. 205-207 and 270-271) 2.5 meters of sea level rise will take hundreds of years. So the coastal nuclear power plants will have been decommissioned long before then.

You may have to look carefully at what "decommissioned" means locally. I'm not sure that all these sites are owned and regulated such that it doesn't result in some of them being only partially dismantled and then ignored.

And places like Dounraey aren't decommissioned yet, and keep getting handed between different organizations for decommissioning to happen.

Fair enough, a costal site might still have radioactive material in a few hundred years time.

dyqik wrote: ↑

Sun Sep 27, 2020 11:28 am

You may have to look carefully at what "decommissioned" means locally. I'm not sure that all these sites are owned and regulated such that it doesn't result in some of them being only partially dismantled and then ignored.

And places like Dounraey aren't decommissioned yet, and keep getting handed between different organizations for decommissioning to happen.

The usual UK decommissioning plan is defuel and maybe remove any easily removable nasty bits, then "care and maintenance" for a few decades while the rest cools down before moving into a deconstruction/demolition phase. But once it's defueled, there's no risk of a serious accident and stopping radioactive stuff leaking slowly into the sea won't be in our top hundred list of problems.

Sciolus wrote: ↑

Sun Sep 27, 2020 4:51 pm

dyqik wrote: ↑

Sun Sep 27, 2020 11:28 am

You may have to look carefully at what "decommissioned" means locally. I'm not sure that all these sites are owned and regulated such that it doesn't result in some of them being only partially dismantled and then ignored.

And places like Dounraey aren't decommissioned yet, and keep getting handed between different organizations for decommissioning to happen.

The usual UK decommissioning plan is defuel and maybe remove any easily removable nasty bits, then "care and maintenance" for a few decades while the rest cools down before moving into a deconstruction/demolition phase. But once it's defueled, there's no risk of a serious accident and stopping radioactive stuff leaking slowly into the sea won't be in our top hundred list of problems.

Given that the usual thing to do with spent fuel is to leave it underwater I'm not massively worried about flooding of the basements of reactors compared to, as you say, the other hundred problems.

Maybe if we'd had more nuclear reactors the Antarctic ice would be at less risk of melting.

The problems at Fukushima were because the generators were also in the basement, and the momentary 9-metre rise in the sea level.

Bird on a Fire wrote: ↑

Fri Sep 25, 2020 3:21 pm

It would be entirely doable to limit carbon emissions and thus climate change to lower levels, and thus reduce the amount of locked-in melting. But we'd have to accept expense and inconvenience immediately, rather than drawn out over several centuries.

Presumably that's why most of the people striking for climate action are kids, and most of the people tutting about it are older folks who'll be safely dead so would rather not sacrifice anything for a collective effort.

This is silly. The scale of the challenge is enormous, and I'd be interested to understand how this "doable" transition works in terms of "inconvenience" and "expense".

I'm someone who thinks we should make profound changes to the way we live to try and solve this problem, but as an ugly old grizzled bastard I also have an inkling how difficult that will be. Our economy will be f.cked over during the transition unless it has buy-in from the incumbent powerhouses, and this won't happen because it will directly challenge vested interests.

"The economy" in a capitalist system is just a way of defining "the ability of people to have a semblance of control over their lives". Poor people will be f.cked if we close down commuting, transport for leisure, current farming practices, non-renewable energy sources, inefficient housing etc without buy-in from the vested interests that currently run the show. But the vested interests are not going to to do this stuff in a hurry, partly because we're all entirely dependent on them to keep the cash flowing.

To achieve the kind of changes we need in the time we have will take the kind of authoritarian governments that kids in Portland are going nuts about, except it'll be Green Trumps. So adaptation is absolutely something that needs to be considered.

Most of the tech we need is ready. The political will isn't, but can be changed rapidly.

We already know how to decarbonise energy production, and electric vehicles are nearly ready for most use-cases. What we need is a binding, adequate target to focus action. So we say, "net zero by 2030, no new fossil power stations, no new fossil-powered cars, no more fossil industry subsidies". Whack a carbon tax on everything, including land-use, to penalise businesses and governments that don't get with the program.

That gives two bits of wiggle-room - 10 years to come up with a plan and iron out problems with it, develop additional tech and car-charging infrastructure and whatever, but massively aided by clear, legally binding commitments serving as an obvious signal to business as to where their future lies.

The other bit of wiggle room is the word "net" - there's be some maths involved, but the unavoidable bits of emissions (aviation and shipping don't seem to be quite ready to fully decarbonise, yet) can be offset through ecological restoration, which is currently the most proven and scalable carbon-sequestration tech we have: rewetting and creating wetlands, allowing forest regeneration, regenerative agriculture to improve soils, etc. I'm not opposed in principle to other carbon-sequestering technology, but I'm not aware of any that are as reliable and that deliver so many side benefits (from mitigating flood risk, improving & diversifying the food supply, and providing cleaner air and recreational access to nature to urbanised populations).

It would cost a lot, but obviously that investment would reap rewards in two ways: the standard "Keynesian" economic stimulus, as well as reducing risks in the long term. Some people would lose their jobs, but could be retrained by diverting subsidies and tax breaks from fossil industries to workers' retraining/compensation.

Whatever you think of the scale of the challenge - and I'm not underestimating it - it's far smaller than the scale of the challenge of adapting to climate change (which is obviously necessary too, not least because so much harm is already inevitable). The default position of intelligent, informed people needs to be pushing for more political progress, not hand-wringing about how tricky everything is.

Most vested interests don't actually give a f.ck about where electricity comes from. Fossil fuel companies' wealth and power is now dwarfed by tech giants, many of which are presenting a green face to the world. Most people in the world want more action, despite their personal circumstances. Banks, investors and regulators are all waking up to the carbon bubble - but slowly. Really, all that's needed is to emphasise and enhance current trends, supporting the current engines of progress and holders of (much) power. Accelerating a shift, not starting a revolution.

You’re not factoring in the inertia in the economic system when you judge which option is “easier“. This makes adaptation easier, at least right now.

TopBadger wrote: ↑

Sun Sep 27, 2020 7:43 am

Woodchopper wrote: ↑

Sun Sep 27, 2020 4:50 am

Bird on a Fire wrote: ↑

Fri Sep 25, 2020 11:34 pm

More generally, loads of coastal areas have been used for landfill, military and fuel dumps, etc. So there's lots of extra pollution to leach out into the coastal shallows of Hampstead-super-Mare.

I’ve been looking at the flood map. https://www.floodmap.net/

With three meters (it doesn’t seem to like decimals) Cambridge, Dagenham and Doncaster are all near the sea shore.

Wowzers. The isle of Ely will actually become a bonafide island.

again. Ely was an island until the fens were drained, as recently as the 17th century. https://www.historic-uk.com/HistoryMaga ... onsUK/Ely/

plodder wrote: ↑

Mon Sep 28, 2020 10:14 pm

You’re not factoring in the inertia in the economic system when you judge which option is “easier“. This makes adaptation easier, at least right now.

I'm pretty sure I mentioned it a few times - carbon tax, carbon bubble, etc.

The problem with "easier right now" is there isn't really a "later" when we can do things. We have a couple of decades, max, to limit warming to so-called 'safe' levels, and nothing will happen overnight. We need to get on with things.

For almost all of human history, the "economic system" has been a tool for, and a consequence of, society. It seems to be incredibly recent that anyone would suggest that all the governments in the world can't take the necessary steps to literally save out environment* because of "inertia in the economic system". Yes, investors would have to divest from fossil fuels quicker than they're already doing. Yes, governments would have to print money, like they did just last decade because the financial sector spaffed it all up the wall being c.nts. It's all been done already, it just needs to happen faster. Get on with it.

*I think this is the best wording for the concept - saving the conditions in the biosphere on which human civilisation has thus far depended

The economic system has been massively disrupted this year already. Which means it's easier to redirect it a bit right now - this is the "build back better" thing going on over here, at least.

dyqik wrote: ↑

Mon Sep 28, 2020 10:37 pm

The economic system has been massively disrupted this year already. Which means it's easier to redirect it a bit right now - this is the "build back better" thing going on over here, at least.

And one of the lessons from this year is that the IT infrastructure is ready to support a big drop in commuting and business travel.

Bird on a Fire wrote: ↑

Mon Sep 28, 2020 10:16 pm

TopBadger wrote: ↑

Sun Sep 27, 2020 7:43 am

Woodchopper wrote: ↑

Sun Sep 27, 2020 4:50 am

I’ve been looking at the flood map. https://www.floodmap.net/

With three meters (it doesn’t seem to like decimals) Cambridge, Dagenham and Doncaster are all near the sea shore.

Wowzers. The isle of Ely will actually become a bonafide island.

again. Ely was an island until the fens were drained, as recently as the 17th century. https://www.historic-uk.com/HistoryMaga ... onsUK/Ely/

Bonafide island! Previously Ely was an "island" in the sense of higher dry ground surrounded by freshwater swamps. This would be an island surrounded by open seawater.

That map puts my house right on the waterfront at +10m sea levels.

That map is very cool, thanks chops.

I'm quite surprised that my road seems to be safe till 10m too, as we're only two streets from the waterfront. Our flat's upstairs, though, so no worries anyway. Actually I'm a bit relieved because we're in a seismically active zone and I couldn't afford the earthquake premium on our house insurance, so it's good to know we're out of reach of a moderate tsunami.

My office starts to go under at 3m, which gives me a decent chance of bunking off for a few days later this century. They're building new fancy apartments even closer to the water than that, so it'll be fun if there's a big flood again here.

My house is at 60ish m, and all my places of work are on top of hills.

If they all go under, something has gone very very wrong.

That said, one will get considerably lower if Antarctica melts entirely.

Bird on a Fire wrote: ↑

Mon Sep 28, 2020 11:22 pm

I'm quite surprised that my road seems to be safe till 10m too, as we're only two streets from the waterfront.

The big difference is that I'm over an hour drive from the coast!