Isn't a 5 - 8 degree rise catastrophic though? Genuine question.
Actually, the biggest danger is that political instability brought on by climate change will lead to nuclear war. That would be much worse than losing civilization to climate change because it would happen much faster, essentially instantaneously. That is not at all unlikely even under much more modest warming scenarios.
But homo sapiens will probably survive, and so civilization will probably eventually be rebuilt
Cleverness is a huge advantage in the survival game.
Edit: one way humans will extinctionize our species:
https://phys.org/news/2017-02-scientists-categorize-earth-to...
We're basically driving this car full speed towards the cliff. No amount of cleverness will stop this.
Just because humans are slightly more clever than past dominant species doesn't make us any less extinction-proof.
Ants, individually, are stupid. Collectively, they're intelligent, and solve complex problems.
Humans, individually, are brilliant (by animal standards). Collectively, not so much.
The good news is that runaway greenhouse warming won't evaporate oceans and bake out CO2 from surface rocks :)
[1] http://www.un.org/esa/sustdev/natlinfo/indicators/methodolog...
This is definitely not true for the US. At least not by any global notion of political instability. The US government isn't near collapse, there is a very limited likelihood of any kind of coup, the economy is doing very well, and riots have been very rare.
There is a lot of political bickering, but it doesn't seem to be any more-so than during the last party-in-the-office changes (Clinton to Bush, Bush to Obama).
A seawall isn't just a wall, it's more like a dike if it is to survive and that means it has a width many times larger than it's height.
And then there is seepage to contend with. This is anything but a trivial problem and we have never done engineering on that scale before.
The easiest solution would be to move to higher ground.
I'm sure walls are an option, but they will be expensive to maintain and it doesn't take much to have big consequences. https://en.wikipedia.org/wiki/Drainage_in_New_Orleans
If that's the bar for civilization ending, then civilization ended when people came to the US, ended again when they expanded out to the West, etc.
Just because people on the US coasts move means little to the 60 percent of citizens that don't live near the ocean.
And again, it's not going to happen overnight. A wall of water isn't coming in that will force everyone to put their things in a car and go. It will be slow build-up that slowly forces people out as they decide it's to expensive to mitigate.
Interesting that your example is literally true both times for the people who where there earlier.
Can you please elaborate on this point?
The Green Revolution was through picking all the low-hanging fruit - hybrid crops and synthetic fertilizers. Increasing yield to match demand is already looking like an issue without the effect of catastrophic climate change. Other issues occurring in the next 20-30 years include encroachment of cities into prime arable land, land degradation, and increased cost/reduced availability of phosphorous fertilizers.
It's a massive issue that barely registers on the public conscience, and we may hit the perfect storm soon, particularly if a new nasty rust or plant virus pops up on the scene at the same time.