Sea rise tracked back
New research suggests global sea level rise has been occurring decades longer than previously thought.
It found a jump in the rate of sea level rise from the 1960s, caused mostly by the expanding of the oceans as they warm up.
That thermal expansion drove sea level rise until the 1990s, when glacial melting overtook thermal expansion as the dominant force.
Lead researcher Sonke Dangendorf from the University of Siegen in Germany says many believed current rises stemmed from the nineties.
“The acceleration detected over the recent satellite period already started in the 1960s [and] has proceeded to present day,” he said.
“The sea level acceleration detected over the recent satellite period seems to be strongly dominated by ice melt, and in particular by the accelerated mass loss of the Greenland ice sheet.
“Also, the mass loss from the West Antarctic ice sheet is now increasingly contributing to accelerating sea level [rise].”
Global sea levels have seen average rises of 3.1 millimetres per year from 1993 to 2015, with that average having increased from 2.1mm to 3.4mm per year during that period.
But sea level rises are not uniform worldwide, and some of the greatest sea level rise has happened on Australia’s east coast
“A further very interesting and important result is the finding that the global sea level acceleration has mainly been dominated by the southern hemisphere, with largest values obtained in the subtropical Pacific, east of Australia and New Zealand,” Dr Dangendorf said.
Experts say that under a business-as-usual scenario, the rate of rise will be more than 10mm per year by the end of the century.