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Comment by geoid | Hacker News Reader

This is correct. The earth is ductile at long time periods, and mountains maintain isostatic equilibrium as the tops are eroded away. The article quote is absurd. Source: my earth science PhD.

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Yes, you're right, it is the isostatic unloading that they're referring to - but in regards to the 'sucking', they seem to mean that the semi-localised unloaded of the top of crust (via rain, river incision) creates a zone of lower lithostatic pressure, and so that area ends up getting pushed up to maintain isostatic equilibrium. Not truly a 'sucking', but as an analogy, I think it's OK. It's more easily seen as part of the critical wedge angle for fold and thrust belts.

Does anything truly 'suck'? When you drink a milkshake with a straw, the milkshake is pushed up your straw by the atmosphere..

Exactly, good point. It is convenient short-hand term, and in the case of climate forcing tectonic activity, it works well, I think.

Fair. 'sucking' does work to describe the unloading. I guess the idea that the _speed_ of the erosion creates suction, is what bothered me.

I love your username. I spend a lot of time with Census Tigerfiles. GEOID is life!

Thanks. There's another meaning of geoid, which is the shape of mean sea level of the globe. The height of sea level varies according to the local strength of gravity. When they first put up satellites that could accurately map sea level, it gave us the amazing maps of the sea floor. Basically, the sea surface subtly mimics the features of the sea floor.

I think I recall being thaught that water followed the gravity pull which was greater around the equator than the poles which would explain why with the poles melting, the equatorial regions would be the most affected by the subsequent seas rise. Is this wrong? Where can I see a good sea map? Thanks!

Guess I just went and looked at a Geoid map and I was lied to, EU is in big trouble!

Maps are here:

https://topex.ucsd.edu/grav_outreach/

Yes, water does follow the gravity. I'm not a climate person, and it's a complicated system, but as I understand it, new melt would be distributed evenly by mass around the globe, which means a larger volume of water at the equator due to higher temperatures there. My hunch in that changes in wind patterns and currents will be the more important effect though.

According to an article I read recently, the reason that equatorial reasons will see the greatest rise in sea level is that ice currently exerts a significant gravitational pull. As ice melts, that gravitational pull is reduced, causing sea levels to fall in the vicinity of the melting ice and to rise far away from the source of the melting.

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