NZ 'must prepare for warmer climate'

New Zealand should be stamping out rock snot and stepping up efforts to beat rats and possums to prepare for global warming.

Roger Jones, a visiting expert on climate change risk from Victoria University in Melbourne, said New Zealand should work harder at wiping out invasive plants and animals to get native species as healthy as possible to adapt to future climate change.

Dr Jones, in Wellington last week to speak at the New Zealand climate conference, said neither this country nor Australia was spending enough to get native eco-systems in shape. Natural eco-systems were so complex scientists did not know how they would react.

"We don't know what's going to happen so the best protection is to keep it in a healthy state."

Scientists at the conference looked at how Kiwis could prepare for two possible futures at the lower and upper ends of IPCC predictions for global warming.

Environment Minister Nick Smith said New Zealand was likely to warm by 1C by 2040 and 2C by 2090 no matter how successful efforts to cut greenhouse gases were.

Sea level rises of 20cm mid-century and 50cm by the end of the century were likely, as well as more rain for the west and more droughts for the east, he said.

Landcare ecologist Matt McGlone, who also spoke at the conference, told the Herald New Zealand's remaining patches of biodiversity were already stressed by pests and weeds. Climate change would add another stress.

Dr McGlone said intense development of parts of the coast and major estuaries had backed coastal eco-systems into a corner.

Estuaries and sand dunes would normally move inland or outwards in response to changing sea levels.

But in many places they would now strike roads or sewage ponds directly inland, he said.

"In many places people's houses are just behind the dunes."

Dr Smith wants the Ministry for the Environment to come up with a national policy on sea-level rise to help councils direct new coastal development.

Dr Jones, a professorial fellow at the Centre for Strategic Economic Studies at Victoria, said councils should vary their approach to new building near the coast depending on what was at stake.

"If you're building a boatshed you might not worry too much about sea level rise, [but] if you're building a hospital ... you would kind of prepare for the worst," he said.

Dr McGlone noted New Zealand was relatively safe from the severe climate effects likely to be felt in the centre of continental countries such as Australia or in low-lying or very small states. Westerlies would probably increase.