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Sea levels are rising faster than scientists thought: Climate change has triggered acceleration, claims study

 

Sea levels have risen faster than expected in the last 20 years as a result of global warming and other factors, according to new research.

The study claims that estimates for sea level rises between 1901 and 1990 were too high due to incomplete records.

But from 1990 to 2010, sea levels were correctly predicted to be rising faster than ever before.  

This caused a discrepancy in which the slower sea level rise seen in the last century caused the increase in recent years to appear even more rapid.

The study was carried out by scientists at Harvard University in Massachusetts. 

Incomplete records from previous estimates of global sea-level rise in the 20th Century had been overestimated by as much as 30 per cent, they say.

And the new figures suggest that in the past two decades, since 1990, the rate of sea-level rise has accelerated more quickly than previously believed.

Since 1990 global sea levels have risen by about 3mm (0.12 inches) annually as the ice caps and glaciers melt because of rising temperatures.

Previous estimates had placed sea-level rise at between 1.5mm and 1.8mm (0.06 and 0.07 inches) annually from 1901 to 1990 - but now that figure is thought to be closer to just 1.2mm (0.05 inches).

RISING SEA LEVEL ESTIMATES 

Previous estimates had placed sea-level rise at between 1.5mm and 1.8mm (0.06 and 0.07 inches) annually from 1901 to 1990. 

But, now that figure is thought to be closer to just 1.2mm (0.05 inches). 

When looking at the more recent figures, from 1990 and 2010, they found the estimates and the actual rising levels more closely matched - at around 3mm (0.12 inches) per year.  

The slower sea level rise seen in the last century causes a discrepancy. 

And this gap in the figures makes the increase in recent years appear even more rapid. 

Scientists claim that the rate of increase in rising sea levels has, therefore, been underestimated by about 0.6mm (0.02 inches), overall. 

The slower sea level rise seen in the last century causes a discrepancy. 

And this gap in the figures makes the increase in recent years appear even more rapid. 

Scientists claim that the rate of increase in rising sea levels has, therefore, been underestimated by about 0.6mm (0.02 inches), overall.

Dr Eric Morrow in the Department of Earth and Planetary Sciences 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.

'Another concern with this is that many efforts to project sea-level change into the future use estimates of sea level over the time period from 1900 to 1990.

'If we've been overestimating the sea level change during that period, it means that these models are not calibrated appropriately, and that calls into question the accuracy of projections out to the end of the 21st century.'

Dr Carling Hay, from the same department, added: '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.'