Sea levels around the world are already “significantly higher” than most scientific estimates assume, according to new research. It appears that coastlines are even more vulnerable to rising ocean levels as a result of global warming.
A study by Wageningen University in the Netherlands found that actual sea levels are on average about 30 cm higher around the world than estimates generated by standard scientific models, writes the Financial Times.
The gap between models and reality varies markedly around the world and is greatest in Southeast Asia and Oceania, where on some coasts ocean levels are one to 1.5 meters higher than most impact assessments assume.
Philip Minderhoud, project leader, said the study, published in the journal Nature, will change perspectives on the need for coastal adaptation and protection.
“Simply put, if sea level is actually higher for a given island or coastal city than previously expected, the effects of sea level rise will appear sooner than expected,” he said, quoted by the FT.
Wageningen scientists have estimated that the one meter of sea level rise that many oceanologists predict will occur by 2100 as a result of the melting of ice caps and the thermal expansion of seawater will result in between 77 and 132 million more coastal people living below sea level than previously expected.
Why the discrepancies? The reason is that the vast majority of sea level research to date is based on measuring the height of coastal land using models based on Earth's gravity and rotation.
“In fact, sea level is influenced by additional factors, such as winds, ocean currents and sea water temperature and salinity,” said Minderhoud, quoted by the FT.
His colleague Katharina Seeger said that only 1 percent existing scientific publications “correctly combine land height and sea level measurements and relate to the actual measured sea level.”
Source: Financial Times
