Rob Fenwick: Sea levels set for dramatic rise

Polar scientists are united on the likelihood of level rises - but how much and when? When 2500 polar scientists gathered in Oslo this month to compare notes at the conclusion of the International Polar Year, a common thread ran through their presentations and papers:

"Unless we better understand the probable melt rate of ice in Antarctica and Greenland we haven't a hope of being adequately prepared for the inevitable sea level rise in the decades ahead."

The conference, described as the largest gathering of polar scientists ever, saw satellite data from both poles, including images and ice elevation calculations, which confirmed the annual melt in the Arctic and Antarctica was faster over the last summers than most had predicted.

Antarctic geologists from New Zealand, key players in the Antarctic Drilling Project (Andrill) in the Ross Sea, explained how the rate of ice melt won't be linear.

Rather there will be a cumulative, run-away effect as the greenhouse influence raises ocean temperatures, shifts ocean currents and alters the frequency of climatic events.

Data from Andrill enables scientists around the world to model what is likely to happen to the two massive polar ice sheets at each end of the Earth as temperatures rise, based on an extensive range of data - geological, biological and climatic - hidden within the rock cores when similar climatic events occurred millions of years ago.

Award-winning climate palaeontologist Tim Naish from Victoria University, whose findings were published in the prestigious Nature journal last year, noted that the last time CO2 levels in the atmosphere were as high as now, the average global temperature was as much as 5C warmer.

It is also becoming apparent that the height of sea level rise will differ from one land mass to another around the globe, depending on its latitude and the volume of ocean surrounding it.

There is now little doubt we're all going to have to adapt to a sharp increase in sea level, which in many parts of the world will have unimaginable social and economic consequences.

New Zealand scientists, with their acknowledged expertise and experience operating in Antarctica, will continue to play a key role in the quest for more certainty around when, where and how much.

* Rob Fenwick attended the IPY Conference in Oslo, Norway in his capacity as chairman of Antarctica NZ, the Crown entity responsible for developing, managing and executing New Zealand Government activities in Antarctica and the Southern Ocean, in particular the Ross Dependency.