Eli5: How does glaciers melting cause the oceans to rise?


If global warming causes glaciers to melt, how does that increase the water level if there is still the same amount of water, but in different forms (liquid and solid)?
Like if you have a glass of water with ice cubes in it filled to the brim, and the ice melts, the glass doesn’t overflow…

In: Chemistry

Because a lot of the ice of the glaciers are above sea level. A more accurate comparison would be a glass of water with ice somehow stacked wayyyy above the brim then left to melt.

The problem is that these glaciers are on land not on water… thus when they melt the add water to the ocean. This, in turn, causes ocean levels to rise.

Glaciers are ice on land, ice melts and the water goes into the oceans. The Greenland ice sheet is losing about 250,000,000,000 metric tons of ice per year.

2 main reasons I know of:

The melting ice isn’t all floating, a lot is on land.

The ice that is floating tends to be freshwater, rather than salty, so it displaces less liquid than it contains. Think along the lines of an ice cube in a glass of custard, but obviously closer in density.

Definition of glaciers is a huge chunk of ice on land, not in the sea at all. Sea-ice is the name given to ice shelves which sit in the sea at the North Pole and around the edges of Antarctica and Greenland. The polar ice caps is what we call the huge masses of ice on land on Greenland (north) and Antarctica (south).

Most of the sea level rise we have experienced in recent decades has actually been from the thermal expansion of water as the surface layer of the sea all around the world warms up slightly. Only in the last few years has the contribution of glacial melt water overtaken thermal expansion of seawater in terms of how much is going towards rising sea levels.