Key Points:

New Zealand could become a climate change lifeboat, swamped with returning expats, Australians and thousands of refugees from the Pacific as the weather plays havoc around the globe.

A book launched in Auckland tonight, with Climate Change Issues Minister David Parker as a guest speaker, focuses on the impact of global warming on New Zealand.

Hot Topic author Gareth Renowden explores the latest evidence from the fourth assessment report of the inter-governmental Panel On Climate Change in a New Zealand context.

Renowden, a science writer from North Canterbury, said New Zealand would not feel the rate of change as much as most countries as it was surrounded by the vast Southern Ocean which would warm relatively slowly.

That meant New Zealand would be perceived as a good place to live and its agriculture would even get a boost from the extra warmth.

"What happens if climate refugees from the Pacific or Asia knock on the door, or our half-million expat Kiwis all decide to come home to ride out the rigours of climate change?"

Colleagues living overseas were asking when they should return.

"They want to know which signs they should look for showing that climate change is happening. My answer is to look at the Arctic and when large chunks of Greenland turn into ice cubes ... What's happening there is already dramatic. If it gets worse, get worried."

Renowden said it was possible that Australians, who could live in New Zealand as of right, might want to shift here as the heat there turned up, with more droughts, a greater risk of bush fires and increased stresses on water and agriculture.

Pacific nations faced more intense tropical cyclones and rising sea levels which penetrated groundwater and increased the risk of storm surges.

"If we are seen to be a good place to escape the worst of climate change, lifeboat New Zealand could quickly become overcrowded. Managing immigration will be even more of a political hot potato if thousands of people are knocking at the door."

Land values and house prices would inevitably increase, he said.

Despite New Zealand coming off quite well, it was not totally off the hook.. Isolation would again present challenges because of the volumes of food miles incurred in exporting.

An increased focus on carbon footprints and more carbon labelling would become an important challenge.

"It is already big in Britain and beginning to be in Europe and spreading around the world ... It's important that businesses be proactive and creative in addressing such issues."

Renowden said low-carbon shipping would be sensible.

Already considerable work had been done overseas to provide wind power for cargo ships with computer-controlled aerofoils or large kites .

Such systems not only cut fuel costs, and therefore carbon emissions, but fitted nicely with New Zealand's image as a sailing nation, he said.

"I'm looking forward to seeing the first New Zealand-built wine clipper arriving in the port of London - clean, green, carbon neutral and a fantastic bit of national PR."

Renowden said governments should consider how the economy might respond if air travel was limited.

Air New Zealand could consider strategies like funding large scale possum control so regenerated native forest could offset long-haul emissions. The airline and tourism industry would enjoy a strong selling point.

Electricity and carbon-based fuels were also pivotal issues, he said.

"Building a low carbon energy infrastructure might mean wind farms in iconic landscapes or more hydro power in fragile river systems. Weaning our transport system off fossil fuels could transform agriculture and the landscape as crops are grown for biofuels."