As global warming proceeds, sea level is rising, partly because of thermal expansion and partly because of meltwater from disappearing icecaps and glaciers. Coastal cities are expected to be flooded as a result. By how much would sea level go down if all the ships in the oceans are removed? The world’s oceans have a surface area of about 3.5 × 10¹⁴ m² and the mass of all the ships afloat is roughly 1.8 × 10¹² kg.