It’s not only water processes that play a role in global sea level rise – ground movements can play a significant role as well. On a continental scale, Earth’s crust is still recovering from the last ice age. Around 20,000 years ago, Canada, the northeast United States, Scandinavia and other regions were weighed down by ice sheets. As these ice sheets melted and the weight on the continents eased, the land surface slowly rebounded. This rebounding process, and related subsidence, continues to alter the shape of ocean basins today.
Subsidence can also result from human activity, like resource extraction. The Mississippi River Delta, for example, is essentially drowning as sinking ground is combined with higher sea levels. NASA is studying this case with an airborne campaign designed to study how sediments are accumulating on the delta.