Study: sea levels rising quicker than previously estimated

Sea level rise is accelerating at a much faster pace than previously estimated, according to a new study from Harvard University. The findings have implications for climate change models.

The study, which has been published in the journal Nature, found that global sea level rise from 1900 to 1990 had be overestimated by as much as 30%. Suggesting that the rate of change is far more rapid than previously thought.

Co-author of the study and a recent Ph.D graduate in Harvard’s Department of Earth and Planetary Sciences (EPS), Eric Marrow said, “What this paper shows is that sea-level acceleration over the past century has been greater than had been estimated by others. It’s a larger problem than we initially thought.

“Scientists now believe that most of the world’s ice sheets and mountain glaciers are melting in response to rising temperatures. Melting ice sheets cause global mean sea level to rise. Understanding this contribution is critical in a warming world.”

Previous estimates had placed sea level rise at between 1.5 and 1.8 millimetres annually in the 20th century. The latest study found that from 1901 to 1990, the figure was closer to 1.2mm. However, it is agreed that global sea level has risen by around 3mm annually over the last two decades, indicating that climate change is having a much greater impact because the rate of change is faster than anticipated.

Co-author Carling Hay, a postdoctoral fellow at EPS, added, “We expected that we would estimate the individual contributions, and that their sum would get us back to the 1.5 to 1.8mm per year that other people had predicted.

“But the math doesn’t work out that way. Unfortunately, our new lower rate of sea-level rise prior to 1990 means that the sea-level acceleration that resulted in higher rates over the last 20 years is really much larger than anyone thought.”

Photo: NOAA’s National Ocean Service via Flickr 

Further reading:

Greenland ice melt and sea level rise ‘greatly underestimated’

How fast is sea level rising?

Antarctic winds could accelerate sea level rise

Thousands of US cities at risk of sea level rise

Antarctic sea levels rising above global average