Rising Waters: Our Dynamic Earth

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 gradual lift, the recovery from the last ice age as well as ice that is melting today, continues to alter the shape of ocean basins.

Rising sea levels can also be compounded by sinking land. Land can compact as people pump water, oil or natural gas out of the ground. The Mississippi River Delta, for example, is essentially drowning as sinking ground is combined with higher sea levels. NASA is studying this case with a field campaign designed to study how sediments are accumulating on the delta.