[koops]

The US east coast has post-glacial rebound and Atlantic meridional overturning circulation slowdown to compound their sea-level problems. But most the rise is nothing special compared the rest of the world, which is the worst part of this.

[njarboe]

Calculating what the sea level rise will be if certain amount of ice melts is quite complicated because of gravitational attraction due to the large mass of the ice, changes in ocean circulation due to the temperature and saltfree content of ice meltwaters, change in the earths axis of rotation due to ice melt, change in ocean currents, etc.

When part of the Greenland ice sheet melts the global mean sea level rises, but it is likely to cause sea level drops in some places around the northern Atlantic. How and where is going to be almost impossible to model and we will just have to wait and see how it plays out. Journal articles here [1,2]

[1] https://link.springer.com/article/10.1007%2Fs10584-010-9935-... [2] https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/201...

[jackcarter]

Won't post-glacial rebound counteract rising sea levels?

[koops]

Unfortunately no, not here. The metaphor I've heard is continent as couch cushion: the glacier was "sitting" on the upper part of North America, pushing up the edges. Now that weight is gone, the coasts are dropping slightly.

[jackcarter]

Ah, that’s interesting and believable. Do you know where you heard that?

I found this article, which talks about a slightly different effect: If Antarctic ice melts more quickly than arctic ice, then the Antarctic land rebound will shove southern-hemisphere water north, raising sea levels in the northern hemisphere. The opposite effect happens if arctic ice melts before Antarctic ice.

https://www.theguardian.com/commentisfree/2018/oct/01/cities...

[wcoenen]

The article doesn't even mention the effect of gravity, which is also significant. Ocean water is currently gravitationally attracted to the ice caps, and when an ice cap disappears, all that "bunched up" water will spread around the globe. This effect reduces sea level rise in a large area around the ice cap, and increases it everywhere else.

This other article in The Guardian does mention it: https://www.theguardian.com/environment/ng-interactive/2018/...

[koops]

Here the Woods Hole oceanographers talk about it without the couch analogy:

https://www.whoi.edu/news-release/why-is-sea-level-rising-hi...

[darkerside]

If it's sitting on top, wouldn't it push down? Or do you mean upper as in north?

[zaroth]

It’s fantastic and even mildly hilarious that this is a real effect at such a massive scale.

[jcranmer]

It depends on where you are. If you were underneath the ice sheet (which is Long Island and further north), then you are rebounding since the ice was pushing down on you. If you were further south, then you are slowly sinking due to the rebalancing of weight.