Global warming may have already passed irreversible tipping point

[Forogil]

You're assuming some orderly structured rebuilding operation that would replace all cities/ports in a timely fashion.

Yes, given that if we are talking about some major sea-level raise (caused by Greenland melting - whether Antarctica will melt is less clear) we seem to be talking about several hundred years; while most of the cities/ports were built in less than a hundred years.

[Shadowferal]

Time is a double-edged blade here.
If the shit kicks in overnight losing infrastructure, livelihoods, and possibly lives, then nations would be sympathetic and donate resources for assistance.
However things are gradual...there's no urgency, and no one wants to admit things will become worse for the simple reason that they don't believe that they need to something now.

[cubby]

Yes, given that if we are talking about some major sea-level raise (caused by Greenland melting - whether Antarctica will melt is less clear) we seem to be talking about several hundred years; while most of the cities/ports were built in less than a hundred years.

I think the topic came up because of the polar ice caps melting (which would cause an approximate 230 sea level rise), not Greenland melting (and I'm not sure about the timeline, impact of Greenland melting - @Endus probably has better info).

Now, I'm not sure what the timeline is for the polar ice caps melting, but I know it's sooner than Greenland. This article suggests by 2035, which is soon, and I believe it uses pretty good data for their timeline. And interesting, Greenland "melting" wouldn't affect sea level rise nearly as much as the polar ice caps. Really the danger are the Polar Ice Caps melting, I think.

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Time is a double-edged blade here.
If the shit kicks in overnight losing infrastructure, livelihoods, and possibly lives, then nations would be sympathetic and donate resources for assistance.
However things are gradual...there's no urgency, and no one wants to admit things will become worse for the simple reason that they don't believe that they need to something now.

If it kicks in overnight I believe we'd be fucked, as a civilization. 200+ foot sea level rise would be the end of most things civilized. For the United States, we'd lose Hawaii and Alaska (collapse because no shipping). We'd lose more than 1/3 of the population's housing, all of our shipping. We'd see riots, famine, and more than likely the collapse of government.

Found an interesting tool that show sea level rise, but it only goes up to 10 feet.

[Bakis]

If 40% of the population lives at what is defined as near or on the coast I wonder what the CO2 emissions would be in order to re-settle.
And I know that mean the poor nations are simply "tough luck".

[cubby]

If 40% of the population lives at what is defined as near or on the coast I wonder what the CO2 emissions would be in order to re-settle.
And I know that mean the poor nations are simply "tough luck".

I think we'd collapse rather than resettle. We'd lose D.C. and all the government infrastructure that would be key to organizing a nation wide resettlement. The military might stay functional, depending on desertion for family (people leaving their station to save their family, etc). Without a functional government and a military to keep order, we'd devolve to local Warlord rulers. Hard to dig out of that.

Globally most island nations would disappear.

[Bakis]

I think we'd collapse rather than resettle. We'd lose D.C. and all the government infrastructure that would be key to organizing a nation wide resettlement. The military might stay functional, depending on desertion for family (people leaving their station to save their family, etc). Without a functional government and a military to keep order, we'd devolve to local Warlord rulers. Hard to dig out of that.

Globally most island nations would disappear.

I should have been clearer. If it even comes close to that we are fucked anyway. All of us.
We just cant go there.

[cubby]

I should have been clearer. If it even comes close to that we are fucked anyway. All of us.
We just cant go there.

Gotcha, agreed.

Also, I think my info must be off a little. I'm seeing articles saying polar ice cap melt by 2035, and that equals 200+ sea level rise. But if that were conclusive (more the timeline than the sea level rise) I would think people would be freaking the fuck out. I keep bugging @Endus for his knowledge/input, and I feel a little guilty, but that guy knows his shit - especially what is good info/articles and what is not.

[Mayhem]

snip

https://www.floodmap.net/, yes I know it's in meters, get with the times.

[Endus]

I think the topic came up because of the polar ice caps melting (which would cause an approximate 230 sea level rise), not Greenland melting (and I'm not sure about the timeline, impact of Greenland melting - @Endus probably has better info).

I'd have to look it up to get the exact figures, but it's somewhere around 30-50 feet of the total that's Greenland, the rest being Antarctica (the remaining glaciers around the world are basically negligible, a couple percent of the total; they're more critical as indicators than in terms of volume).

Now, I'm not sure what the timeline is for the polar ice caps melting, but I know it's sooner than Greenland. This article suggests by 2035, which is soon, and I believe it uses pretty good data for their timeline. And interesting, Greenland "melting" wouldn't affect sea level rise nearly as much as the polar ice caps. Really the danger are the Polar Ice Caps melting, I think.

Hookay. Gotta make some points here.

First, that article is looking at the Arctic ice cap, the Northern pole. That's sea ice, in that it's floating, not landborne. Ice that's floating is already displacing a volume of water equal to its weight in liquid form; you can trivially test this yourself by filling a glass with ice, and then filling it RIGHT to the brim with water so the ice floats, and then letting that ice melt; the water won't overflow. Arctic ice melt doesn't directly contribute to sea level rise.

I emphasize "direct" because losing that ice darkens the albedo of the Arctic seas, meaning they absorb more solar energy, meaning they warm up, which both accelerates further melting, and also causes water to expand; that expansion isn't huge, but when you're talking oceans, it adds up and adds inches to sea level rise.

As for Greenland's lower contribution; see my first response here; it's a much smaller ice sheet than Antarctica's. But it's basically down to those two.

If it kicks in overnight I believe we'd be fucked, as a civilization. 200+ foot sea level rise would be the end of most things civilized. For the United States, we'd lose Hawaii and Alaska (collapse because no shipping). We'd lose more than 1/3 of the population's housing, all of our shipping. We'd see riots, famine, and more than likely the collapse of government.

Found an interesting tool that show sea level rise, but it only goes up to 10 feet.

It's not gonna happen overnight. Best guesses are that melting all of Antarctica is a centuries-long issue. We could easily be on a path that will inevitably bring that about, but it's not gonna happen in our lifetimes. Maybe 500 years or so. That melting is a long-term problem, not a short-term, but it's the kind of thing you'd want to make long-term planning with that taken into account, especially since that'd be centuries of slowly rising sea levels. Remember, even if it takes 500 years, that's 5-6 inches or so of sea level rise every year.

The short-term worry is calving. There's some massive ice sheets that are landborne (and Antarctica has some floating ice sheets, which are the ones calving off icebergs the size of Rhode Island or whatever that sometimes hit the paper; not direct contributers to sea level rise because it's sea ice), and those landborne sheets are cracking. They're also starting to melt from below. That melt tends to "grease" the landscape, so to speak, and if one of those sheets splits off enough and starts to slide, it could hit the oceans, and that would lead to sudden catastrophic sea level rise. We know a massive chunk the size of Arizona broke off the East Antarctic Ice Sheet about 400k years ago, and that it raised sea levels globally by about three meters basically overnight; https://www.sciencemag.org/news/2020...sea-level-rise

That could easily happen again; conditions are comparable and we're accelerating in warming much faster. If it happened, picture a tidal wave 9 feet high rushing around the entire world and then never retreating, and you get an idea of what it would be like.

[Forogil]

I think the topic came up because of the polar ice caps melting (which would cause an approximate 230 sea level rise), not Greenland melting (and I'm not sure about the timeline, impact of Greenland melting - @Endus probably has better info).

As stated Antarctica melting is a more remote possibility than Greenland melting; and if it happens it will be even later.

Now, I'm not sure what the timeline is for the polar ice caps melting, but I know it's sooner than Greenland.

You are wrong. There are two polar ice caps: the Artic one doesn't matter for the sea level. It will have some impact on further warming and be bad for the local wildlife (and good for shipping).

And then the Antarctica one that actually will be responsible for more than 80% of those 230 feet in sea level increase - if it melts, and that will happen after Greenland.

[jonnysensible]

3 degrees by 2100 lets gooooo

[MasonTravis21]

3 degrees doesn't sound like much, but that's plenty on a global scale. I mean, a few degrees change near the poles, and you've got tons of water entering the oceans. 3 degrees will be an issue for folks in 2100. Good thing we'll mostly be long gone by then lol.

[Fuiking]

Let me tell you the story of Venus and how the people there once thought everything would be fine.

Now it's raining sulfuric acid on Venus, maybe let's try not to test the limits of our planet.

Dude.. thats a secret!

[muto]

Shipping operations, and a large part of human settlements are built on the coast - if the coast moves they move with it; rebuilding all harbors and coastal cities in the world will be costly, but can clearly be done on these time-scales - as it has already been done on a shorter time-scale.

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You don't necessarily fill it up to the same level, but a strip mine means that you strip of the top-soil, and then dig/dredge underneath that for the thing you want; so you can just put the waste back and then the old top-soil.

Yeah which they usually don’t on large scale mines. Look up the Homestake mine for example. Been there. It’s literally a crater.

[Edge-]

Yeah which they usually don’t on large scale mines. Look up the Homestake mine for example. Been there. It’s literally a crater.

You're still going on about this strip mine issue off the back of your incorrect assertion that lithium ion batteries cause more pollution than internal combustion cars?

Also, that is not just "literally a crater", it's used for scientific research - https://en.wikipedia.org/wiki/Homest...(South_Dakota)

[Endus]

Yeah which they usually don’t on large scale mines. Look up the Homestake mine for example. Been there. It’s literally a crater.

If you wanna get technical, pit mines aren't strip mines.

[Shadowferal]

If it kicks in overnight I believe we'd be fucked, as a civilization. 200+ foot sea level rise would be the end of most things civilized. For the United States, we'd lose Hawaii and Alaska (collapse because no shipping). We'd lose more than 1/3 of the population's housing, all of our shipping. We'd see riots, famine, and more than likely the collapse of government. Found an interesting tool that show sea level rise, but it only goes up to 10 feet.

Yeah...and PC2 will say "See? It's all good. It pays to be optimistic!

[Forogil]

Yeah which they usually don’t on large scale mines. Look up the Homestake mine for example. Been there. It’s literally a crater.

But it's not a strip-mine.

People often incorrectly use strip-mining for all kinds of surface mining, since it sounds bad. Note that one reason Homestake is not being restored is that it is converted to a science center (primarily solar neutrinos, yes actual science), and it seems that Homestake isn't even a surface mine - as there are a number of deep underground tunnels.

Similarly people use "melting of polar ice caps" to confuse the melting of the Artic (which is happening) with the melting of Antarctica (which would be problematic if it happens, but that's hundreds or thousands of years in the future).

[Endus]

Similarly people use "melting of polar ice caps" to confuse the melting of the Artic (which is happening) with the melting of Antarctica (which would be problematic if it happens, but that's hundreds or thousands of years in the future).

Nitpick; melting in Antarctica is increasing. I believe the most recent data till has deposition outpacing melting, but the Antarctic icecap has been the result of millions of years of deposition outpacing melting. And once that balance tips, it's "only" going to take centuries for it to vanish. And we're on the cusp of that; it's likely the underlying balance has already tipped, and melting simply hasn't increased sufficiently to outpace deposition yet.

That point being passed is something that could happen basically any time now.

[Forogil]

Nitpick; melting in Antarctica is increasing. I believe the most recent data till has deposition outpacing melting, but the Antarctic icecap has been the result of millions of years of deposition outpacing melting. And once that balance tips, it's "only" going to take centuries for it to vanish. And we're on the cusp of that; it's likely the underlying balance has already tipped, and melting simply hasn't increased sufficiently to outpace deposition yet.

That seems unlikely to be that fast, as east Antarctica seem to take a long time to melt.

It took me some time to find someone who had studied it, but - https://www.nature.com/articles/nature17145.epdf "Contribution of Antarctica to past and future sea-level rise" has some reliable data - and even in the "worst case" RCP8.5 the sea level rise after 400 years is "just" 13+/-3 m; and peaks at 20 m in the year 3500; whereas if everything melted (including Greenland - which is included already in 13 m) it would be 80 m.

However, there are obviously uncertainties (including what we will do so far in the future).