Heavy snowfalls push NZ glaciers' recovery

New Zealand's glaciers are continuing to advance as the rest of the world's glaciers retreat, according to the National Institute of Water and Atmospheric Research.

"Over the last three years, the glaciers have gained in mass, halting the declines seen between 1998 and 2002," said the principal scientist at Niwa, Dr Jim Salinger.
But he said recent gains did not compensate for the overall loss in ice mass over the past century due to global warming.

"The iconic Franz Josef Glacier is still much shorter than in 1900, and the volume of ice in the Southern Alps dropped by about 25 to 30 per cent last century.

"This is linked to an increase in regional mean temperatures of 0.7degC."

The good news about our glaciers results from the high volume of rainfall west of the main divide in the Southern Alps, where more than 10m of rain falls each year.

Most of the world's glaciers, with the exception of Norway, lie in low rainfall areas, making them more susceptible to melting in the rising temperatures. This year's advance in the southern glaciers results from greater snow fall in five months between late winter and early summer 2004. Niwa's annual glacial survey undertaken in March records the height of the glacial snow line at the end of summer.

"This reveals how much snow the glaciers have lost and gained during the past year - the lower the snow line, the more the amount of snow that has accumulated to feed the glacier," Dr Salinger said.

"On average, the snow line this year was about 110m below where it would be to keep this ice mass constant."

He said the level of the glacier snow lines is not closely related to the amount of snow that might fall on the country's skifields during winter. "Most of the popular skifields are east of the Main Divide, or in the North Island. Mt Hutt, for instance, gets its snow from big southeasterlies, whereas most of the glaciers are fed by westerlies."

- NZPA