NZ climate change warning - national | Stuff.co.nz

NZ climate change warning - national | Stuff.co.nz

Melting ice sheets, warming oceans and disappearing glaciers could mean New Zealanders have to cope with sea level rises more than triple the international estimates, scientists say.

The most recent Intergovernmental Panel on Climate Changes (IPCC) report projected a sea level rise this century of between 18cm-59cm, unless there is dramatic loss of Greenland and/or Antarctic ice. But international researchers have now upped the ante with some noted academics picking rises of three times that, and some expecting the oceans to lift as much as 2.2m, according to an "emerging issues" paper released today by New Zealand's science academy, the Royal Society. "Recent estimates of future rise are greater than those assessed in previous IPCC reports," the paper said, though it noted that uncertainty over melting and movement of polar ice sheets meant the estimates still had wide ranges. "There have been a flood of new estimates of sea level rise," said Prof Martin Manning, a drafting author of that most recent IPCC report.

Now director of Victoria University's climate change research institute, he told a briefing for science journalists today that new analysis of the main contributing factors had shown loss of glaciers and ice sheets was playing a bigger role than was previously thought. "Basically, all the new estimates are starting to push a bit higher," he said. Melting of glaciers and alpine snowpack were potentially able to raise the world's oceans by between 20cm and 50cm. If major ice sheets melted over very long periods, Western Antarctica could cause 3.5m of sea level rise, and Greenland could lift sea levels by another 7m.

"Some scientists think that Greenland is close to a 'tipping point'," Prof Manning said.