DATE: January 4, 2018
SNIP: The bottom of the ocean is more of a “sunken place” than it used to be.
In recent decades, melting ice sheets and glaciers driven by climate change are swelling Earth’s oceans. And along with all that water comes an unexpected consequence — the weight of the additional liquid is pressing down on the seafloor, causing it to sink.
Consequently, measurements and predictions of sea-level rise may have been incorrect since 1993, underestimating the growing volume of water in the oceans due to the receding bottom, according to a new study.
[Scientists] found that around the world for two decades, ocean basins deformed an average of 0.004 inches (0.1 millimeter) per year, with a total deformation of 0.08 inches (2 mm).
However, there were distinct regional patterns to the seafloor’s bending and stretching, and the amount of sag in certain parts of the ocean bottom could be significantly higher — as much as 0.04 inches (1 mm) per year in the Arctic Ocean, for a total of 0.8 inches (20 mm), the study authors reported.
As a result, satellite assessments of sea-level change — which don’t account for a sinking ocean bottom — could be underestimating the amount that seas are rising by 8 percent, according to the study.