Confirmation of rising seas
Core samples from deep in the Antarctic ice obtained by a Wellingtonbased research team have confirmed climate change models that predict rapidly rising sea levels.
Furthermore, a research paper released by the University of California, San Diego, on March 26 supported the local researchers’ work and found that the Antarctic ice melt has accelerated rapidly since 2003.
Dr Nancy Bertler is the ice core leader of the multi- national Roosevelt Island Ice Core research project, which is based at GNS in Gracefield.
Cores up to 70,000 years old were taken down to 764 metres below the ice surface.
Water and air samples from suspended bubbles have shown scientists what global air and ocean temperatures were in different periods, as well as how much carbon dioxide was in the air, and how ice and sea levels responded.
Bertler said the International Panel on Climate Change predicted in 2010 that global sea levels would rise about 50cm during this century, but that had changed.
‘‘Now we think it will be significantly more than 50cm,’’ she said.
Increased frequency and intensity of storms had already been observed. The severe storm of 2013 was a onein-100-year event, but with a sea level rise of 50cm, storms of that severity were likely to be annual.
‘‘Storms we think of as ‘the storm of the year’ would become a daily event,’’ she said.
The project is also investigating another spectre – the possibility that a ‘‘ melt- water’’ pulse has begun. These have occurred twice in the past 14,000 years.
For a period of between 100 and 200 years, sea levels rise one metre every 25 years.
These melt pulses originate at the West Antarctic Ice Shelf, which feeds the Ross Ice Shelf, where Roosevelt Island is.
The news from the University of California two weeks ago added more weight to the research.
Satellite radar altimeter readings found that West Antarctic ice was melting at a rapidly accelerating rate.
Between 1994 and 2003, 25 cubic kilometres of ice disappeared every year, but from 2003 until 2012, it was melting at 310 cubic km per year.
Apparent growth in the massive East Antarctic Ice Shelf has also stopped and some ice shelves have lost 18 per cent of their thickness over 20 years.
Scientist Dr Nancy Bertler with an ice core from 656 metres below the surface of the Antarctic ice surface. The storage freezer is maintained at minus 36 degrees Celsius.