KEY POINTS:
New Zealand's ecosystems and coastal communities face threats from dramatic changes to the world's climate - and ratepayers face a big burden in paying to combat them.
Niwa scientist Jim Salinger warns the effects will be substantial if nothing is done.
Dr Salinger was the lead author of the Australia and New Zealand chapter in the report of the United Nations' Intergovernmental Panel on Climate Change.
But local authorities - which will have to pick up a big part of the bill - warned last night that they face an almost impossible task.
"We simply can't do all of this to mitigate, to adapt as a nation, and pay for it all out of property tax. It's just impossible," said Local Government New Zealand president Basil Morrison.
Local government will have to pay for upgrading infrastructure such as stormwater networks to cope with heavier rains and protecting the water supply in drought areas.
Mr Morrison said councils would need to look at everything from transport to land use and building controls.
"Are we doing enough? I guess the short answer would be no, not today, if the report was taken in its totality."
The report also contains a warning for the thousands of New Zealanders who live the great Kiwi dream of a home by the beach.
It says areas of coastal development and population growth, such as Northland and the Bay of Plenty, will face rising seas and increases in severe storms and flooding by 2050.
New Zealanders spend tens of millions each year buying properties in these coastal areas.
A fraction under $70 million was spent on new properties on the Omaha Peninsula alone last year.
Real estate agent Michael Dow, who sells about 50 per cent of the properties there at prices averaging $1.3 million, said some buyers asked about the effect of severe weather and climate change, but the risk did little to dissuade people from buying.
Mr Morrison said he was confident council action would accelerate, because it would be unwise not to make any changes.
"It would be like the council saying, 'We're not going to insure our property, because we think it's not going to burn down'."
Greenpeace climate campaigner Vanessa Atkinson said yesterday the Government had done little to counter the threat.
"Our emissions have risen substantially since 1990, and the Government has failed to do the most basic things in terms of climate policy ... "
But Climate Change Minister David Parker said that over the past year policy had been produced on vehicle fleet fuel efficiency, biofuel targets, renewable electricity generation and updating the building code.
Most of the things local councils would need to do to mitigate climate change would not create a lot of extra cost, he said.
Infrastructure upgrades such as to stormwater networks could be staggered.
But a sceptics group, the Climate Science Coalition, said the IPCC report lacked scientific rigour.
Dr Vincent Gray said its climate models had never been properly tested.
"Their projections are nothing more than the opinions of experts with a conflict of interest, because they are paid to produce the models."
Another coalition member, meteorologist Augie Auer, said nothing in the report advanced the scientific understanding of climate change.
"My position is that we can't change the climate of the planet if we wanted to, and there's been no evidence that we can.
"Nature still runs the ball game."
