Southern Alps' ice levels show sharp decrease

Franz Josef Glacier. Photo / Greymouth Star

Ice levels in the Southern Alps dropped by almost 15 per cent in the past four years, new research from climate scientist Jim Salinger shows.

Dr Salinger's new book Living in a Warmer World, launched last night, cites research showing the ice volume in the Southern Alps decreased from 44.08 cubic km in 2008/09, to 37.59 cubic km in 2011/12.

This 14.7 per cent volume loss - which takes in measurements from all the glaciers in the Southern Alps - was an ongoing response to regional warming, Dr Salinger said.

Since official records began in 1977, glaciers in the Southern Alps had lost 30 per cent of their ice.

Forty per cent of this was from the 12 largest glaciers.

Temperature data shows since the early 1900s the regional temperature has warmed by about 1C, and this directly contributed to the ice cover melting. To back this up, Dr Salinger and his colleague Trevor Chinn used research from Victoria University's Brian Anderson, a senior research fellow at the Antarctic Research Centre.

According to Dr Anderson's research model, the ice volume loss recorded since 1977 could be attributed either to the halving of the precipitation level on the South Island's West Coast for the period or an increase in temperature of about 1C, Dr Salinger said.

"Precipitation actually increased in the latter part of the 20th century, whereas temperatures warmed by a degree so its clearly temperature which has been doing it."

Further large losses of ice in the Southern Alps have been projected, he warned. Global warming research by scientists Valentina Radic and Regine Hock calculated a global decrease in ice volume of between 15 and 27 per cent by the end of the 21st century. This was based on global warming projections of 1.5C to 2.5C for the period, Dr Salinger's book stated.

"The largest losses would be in the alps of Europe and Southern Alps of New Zealand." The ice volume loss could be as much as 72 per cent here, the research showed.

"If this scenario comes to fruition, then a mere 14 cubic km would be left cloaking the Southern Alps of New Zealand" - a dramatic reduction since the "Little Ice Age" extent of around 170 cubic km, Dr Salinger said.