Rising temperatures not only threaten to jeopardize marine life due to the loss of oxygen and coral reefs, the temperatures also affect the ice of melting glaciers. The melted water flows into the seas and oceans, causing the sea level to rise and push the seafloor down. This would increase the total height of the water.
Sea levels are usually measured by satellite imagery. According to the study, there is a difference between the measurements by satellites, which use altimeters which can measure the surface of the ocean from the center of our planet, and measurements taken by tide gauges. Tide gauges are instruments that are located at the bottom of the sea and they can measure surface change relative to the bottom. It has measured sea level changes from 1993-2014.
The satellite measurements on the change of the sea levels are off by roughly 8% compared to the measurements by the gauges. However, researchers behind the study, including Thomas Frederikse who leads the study from Delft University of Technology in the Netherlands, explained in the study that only 4% of the measurements could be given to the ocean floor subsiding, as the other 4% is attributed to the sea level rise due to rising temperatures, which causes glaciers to melt, and thus, expand the water causing it to take over more space.