Eustatic change refers to a global change in sea level due to an actual rise or fall in sea level. As global temperatures rise due to global warming more precipitation falls as rain and more ice melts from glaciers/ice sheets, less water is stored on land than sea and as a result sea level increases
When the height of land increases the sea level falls and this is known as isostatic sea level change. Isostatic change also occures when the height of the land decreases - the sea level rises. Unlike eustatic change, isostatic sea level change refers to a local sea level change as supposed to a global. An example of isostatic change is in the period of an ice age when there is a build of ice on the land.