Sea levels rising more quickly than in last 2,700 years

Feb 23, 2016, 2:31 PM EST
Source: MaxGag/flickr
Source: MaxGag/flickr
Scientists have remapped the rising levels of the world’s oceans, and have concluded that the rate of sea level rising over the past century has been “extremely likely faster than during any of the 27 previous centuries.” CNN reports:
Bob Kopp, a climate scientist at Rutgers University who led the research, said in a statement on his website that he and his collaborators had determined with 95% probability that the rate of sea level increase in the 1900s was faster than during any century since at least 800 B.C.
It is not that seas rose faster before that date, he wrote -- but "simply that the reconstruction quality isn't good enough before then" to say so with the same level of confidence.
The researchers estimated, using tidal data and reconstructive techniques, that in the absence of global warming, 20th century sea levels likely would have either receded three centimeters or climbed seven centimeters. That would have been consistent with sea level averages that have held for millennia, tending not to fluctuate more than 7.6 centimeters in either direction per century, as the Guardian notes.
Instead, sea levels appear to have risen by 14 centimeters, or about 5.5 inches, in the past century. About half of observed sea level gains between 1900 and 2000 are likely due to human activity and industrialization, the scientists determined.
The study blames emissions and human activity. The Washington Post adds:
The new research also forecasts that no matter how much carbon dioxide we emit, 21st-century sea level rise will still greatly outstrip what was seen in the 1900s. Nonetheless, choices made today could have a big impact. For a low emissions scenario, it finds that seas might only rise between 24 and 61 centimeters. In contrast, for a high emissions scenario — one that the recent Paris climate accord pledged the world to avert — they could rise as much as 52 to 131 centimeters, or, at the very high end, 4.29 feet.