Eustatisk

Eustatisk refers to changes in global sea level that are not related to changes in the Earth's shape or crust. These are the primary drivers of sea-level rise and fall over geological timescales. The main factor influencing eustatisk sea level is the volume of water in the oceans, which is primarily affected by the amount of ice locked up in glaciers and ice sheets. During periods of glaciation, large amounts of water are sequestered as ice, leading to lower sea levels. Conversely, during interglacial periods, melting ice sheets release water into the oceans, causing sea levels to rise.

Another significant contributor to eustatisk sea level change is the thermal expansion of seawater. As ocean water warms, its volume increases. This effect is particularly relevant in the context of modern climate change, where rising global temperatures are leading to both increased ice melt and thermal expansion. The geology of the ocean basins themselves can also play a role. Changes in the rate of seafloor spreading can alter the volume of the ocean basins, thereby affecting sea level. However, these tectonic influences are typically slower acting than changes in ice volume or thermal expansion. Understanding eustatisk sea level is crucial for predicting future coastal changes and for interpreting Earth's past climate.