Seas Rising at Twice the Rate of 150 Years Ago
A Deep-ocean Assessment and Reporting of Tsunamis (DART) buoy being deployed in the Pacific Ocean from the NOAA ship Ronald H. Brown in October 1999.
Credit: NOAA.

Earth's oceans are rising twice as fast today compared to 150 years ago, according to a new study.

The rise is nearly 2 millimeter per year. At that rate, sea level will be 1 inch higher in 13 years compared to today.

The increased pace is evidence for human-induced climate change, say researchers at Rutgers University, where the study was done. The results are detailed in the Nov. 25 issue of the journal Science.

Professor of geological sciences Kenneth Miller and colleagues examined sediment taken from drill sites along the New Jersey coast to establish a steady millimeter-per-year rise from 5,000 years ago until about 200 years ago. Sea-level measurements since 1850 from tidal gauges and more recently from satellite images reveal the current annual rise of two millimeters per year.

"Without reliable information on how sea levels had changed before we had our new measures, we couldn't be sure the current rate wasn't happening all along," said Miller. "Now, with solid historical data, we know it is definitely a recent phenomenon."

The shift coincides with the beginning of the industrial era, Miller points out, when humans began burning fossil fuels in a big way.

The oceans can rise as glacial ice melts, transferring stored water from land to sea. Most of the current rise, however, is do to the planet being warmer and the water expanding, other scientists say.