- 世界上大部分的冰都在南极冰盖中。世界上所有的冰的融化以及由此产生的液态水在海洋中的扩散将导致地球重心的转移。考虑到上面的1，偏移应该是向北的。地球重心的移动不会显著影响地球陆块和海床的位置，在这种情况下，它们可以被视为海水围绕的固体块。世界各大洋中液态水的分布尽管受到其他因素的影响，但在很大程度上是由将其拉向地球重心的引力所决定的。因此，重心的北移将把更大比例的海水拉到北半球。这些假设大体上正确吗?< / p >
直接从维基百科复制，海平面变化的最简单形式$S$由地球水准面的位移(即，$N$和垂直陆地位置的变化($U$): $$ S = N-U .$$
正是第二个因素，地球和海洋底部对变化载荷的响应，你没有考虑到，这可能导致一些严重的局部偏差，仅从引力方面。
参见图2-2 from http://skb.se/upload/publications/pdf/TR-09-11.pdf，复制如下:
图2-2。 (a)由于冰盖的引力作用，海洋高度向上扰动。由于冰盖的质量，固体地球向下凹陷。(b)由于冰的引力减少(红色虚线表示以前的位置)，加上由于冰盖的质量变小，固体地球反弹(绿色线表示以前的位置)，导致局部相对海平面下降。远场海平面上升是由于融水进入海洋。改编自Tamisiea等人，2003年。在盯着这个数字看了一段时间后，你可能会意识到，确实，从状态(a)到状态(b)，随着冰盖融化，远场海平面上升，这是由于流体水的加入和附近引力的下降。然而，现在冰帽变小了，重量也减轻了，固体地球的反应是向上移动! Hence, 'close' to the ice cap, the sea level doesn't drop as much as you would expect from amount of fluid water + gravity alone. NB: the same happens with the oceans: adding more water to the oceans depresses them, see page 26, figure 11 here https://arxiv.org/pdf/1212.5061.pdf with the 'relative sea level change' around the Mediterranean Sea, compared to the present. Copied here below is one for 10 thousand years ago: 
Apparently, the sea level has risen by 30 meters in the center of the sea, but only about 22 meters on the edges. The reason is that the Mediterranean sea, from 10 thousand years ago to today, gained more mass, which caused it to depress the sea bottom / Earth's crust in the center! Hence, it had to rise even more in the center (compared to the coast lines) to create a flat surface today.
The difficult thing is that these are non-local processes. You kind of need to know about such local Mediterranean changes to make an accurate prediction for the sea level in, e.g., the Gulf of Mexico or so, because it changes the center of mass and the fluid sea water budget that can be distributed!
So with respect to your question, I absolutely think you are right that gravity is an important aspect, and 40 meters relative sea level change differences due in the hemispheres are absolutely possible for the reason you mention. If the melting is instantaneous, this is the main aspect. However, if you wait a century or so, the Earth's deformations start to kick in, can play a serious role, and can dramatically affect the sea level distribution again, in not easily foreseeable ways!