Mostly differences in the geoid [1]. The planet isn&#x27;t perfectly round, and gravity varies quite a lot [2].<p>There are other factors, such as the cold&#x2F;warm water cycle creating very slow currents that push water towards certain landmasses.<p>But as I understand it, gravity is the main cause.<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Geoid" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Geoid</a><p>[2] <a href="http:&#x2F;&#x2F;e360.yale.edu&#x2F;feature&#x2F;the_secret_of_sea_level_rise_it_will_vary_greatly_by_region&#x2F;2255&#x2F;" rel="nofollow">http:&#x2F;&#x2F;e360.yale.edu&#x2F;feature&#x2F;the_secret_of_sea_level_rise_it...</a>