Glacial Melt And Ocean Warming Drive Sea Level Upward

The average sea level around the world has risen a total of 222 millimeters (mm) since 1875, which means an annual rate of 1.7 mm. Yet at the end of this long period, from 1993 to 2009, the sea level rose 3.0 mm per year—a much faster rate. An estimated 30 percent of the sea level increase since 1993 is a result of warmer ocean temperatures that cause the water to expand (thermal expansion). Another 55 percent of the increase results from the melting of land-based ice, mainly from glaciers and the Greenland and Antarctic ice sheets. The other 15 percent of the rise is due to changes in terrestrial freshwater dynamics, such as wetland drainage and lowered water tables.

Read: Glacial Melt and Ocean Warming Drive Sea Level Upward by John Mulrow and Alexander Ochs, with Shakuntala Makhijani Complete trends are available with full analysis, endnote referencing, Excel spreadsheets, and customizable presentation-ready charts as part of our new subscription service, Vital Signs Online.