KEY POINTS:
Jim Salinger and I are talking about the future. The Niwa scientist is tired and rubbing his eyes, but then he has been telling this story for years. There is no Hollywood beat-up about global warming. It is here and it will impact on New Zealand.
And no matter what we and the world do, warming will continue for years to come.
Salinger describes global warming as being like a boiling kettle. Nothing much happens ... then the kettle heats up quickly and boils. "It's exactly the same as the planet Earth."
I ask the obvious question and Salinger ponders, taking it unnervingly seriously. "Are we doomed?"
"It's quite clear we're going to see significant climate change this century," he says. "It's very serious. I'd never believe in being doomed because we're still here, we can do things.
"If we don't the climate will warm and warm and warm, will keep warming and it's a matter of what this will do."
New Zealand is one of the luckier countries. Our island geography and temperate climate will help. But what happens elsewhere in the world will impact on us.
Predictions range through drought, starvation, flood, fire, rising sea levels, and water shortages.
The Stern Report, made public in Britain last week, predicts an economic recession on the scale of the Great Depression. Tens of millions of displaced people will became environmental refugees. Aside from the human suffering, 40 per cent of species could die out.
Scientists and experts here say the consequences for New Zealand, in a matter of decades, could be life-changing - from how we farm to what we drive to the kind of homes we live in.
With warmer temperatures come new pests, weeds, bugs, diseases. One degree warmer is great news for the white-tail spider; and another degree warmer could make New Zealand very homely for snakes.
Climate change will threaten our biodiversity and change our landscape: the kiwi is already threatened and will become more threatened; the snow-capped mountains in the South Island will have less snow.
Climate change could affect our very identity. We are surrounded by ocean and the world's oceans are in big trouble too. The carbon dioxide we release does not just go into the atmosphere. If you think climate change does not matter for New Zealand, think again.
Ice and snow
Al Gore's climate-change film An Inconvenient Truth surveys the world's melting glaciers. Those in New Zealand's do not feature but they are also melting.
To see climate change in action, glaciologist Blair Fitzharris says all you need do is look at Tasman Glacier in Mt Cook National Park. In the early 1980s there were just puddles at the bottom of the glacier. Now, there is a lake of melted glacier measuring more than 1000ha, so big that tourists take boat trips on it.
New Zealand's situation is confused by the fact our two best-known glaciers, Franz Josef and Fox on the West Coast, which had retreated, have pushed forward again in recent years.
Sceptics seize on this as evidence that there is no global warming. Fitzharris and others say they are wrong.
There is a difference between the western and eastern glaciers that is to do with shape and precipitation. The western side has become wetter and the westerlies are stronger and good for the health of those glaciers. And although Franz Josef and Fox have pushed forward they are nothing like they once were.
Our biggest glacier, Tasman, is unlikely to melt entirely but some smaller glaciers are already gone.
Does it matter that our glaciers are melting?
Oh yes, Fitzharris says, for many reasons. When you lose a glacier, vast change takes place in the mountains. Slopes become more unstable and there is a risk of an outburst glacier flood. There are short-term benefits, such as for the Waitaki Catchment in Canterbury, because the rivers get bonus water. But that lasts only as long as the glaciers, then the situation is worse. Glaciers help regulate the river flow and without them the flow regime changes, affecting irrigation.
We live in an alpine country and part of our image, as in The Lord of the Rings, is ice, snow and mountains. This tourist-pleasing landscape could be in for huge changes.
And it matters globally. If we lose the ice, the meltwater contributes to sea-level rise - maybe not by much, but combined with melting glaciers in other parts of the world the sea level could rise by half a metre this century. And if ice in Greenland and Antarctica disappears we are looking at several metres of sea-level rise, perhaps within decades.
Put the "Are we doomed?" question to Fitzharris and he is not optimistic. We are undertaking a great big experiment with our climate system. In the longer term future we are certainly changing the world and we're setting in train some processes which we won't be able to switch off," Fitzharris says.
Peter Wilson echoes some of Fitzharris' concerns. A biologist, formerly of Landcare Research, and a specialist on Antarctic penguins, Wilson raises the matter of oceanic circulation.
If the ice melts in Greenland and Antarctica "you get all sorts of weird things happening - a cessation of the Gulf Stream because the conveyor belt of cold water going back down to the Gulf of Mexico will be disrupted and the warm water won't reach Europe.
"Instead of getting a heating you'll get a cooling in those areas so you'd get an ice age in Britain and overheating in the Equator."
We're not doomed, he says, but the situation is very scary. The increase in carbon dioxide is so far beyond anything we have experenced before. "You're looking at figures which will frighten most scientists."
Extreme weather events
Climatologists predict New Zealand will see more storms, more floods and, paradoxically, more drought.
Look at the Manawatu floods of 2004 and the enormous emotional and financial damage. Or at Matata last year, when torrential rain unleashed huge boulders that smashed people's homes. Scientists might not be able to pin down individual events like these on climate change but they say this is what climate change looks like.
The science is quite clear, Salinger says: "You warm the atmosphere, it holds more moisture, therefore you get more floods."
Extreme weather is expensive. Treasury estimated the cost of the Canterbury drought of the late 1990s at $1 billion.
More droughts are predicted for areas such as Otago and Gisborne.
There have been changes in New Zealand already. Subtropical grasses have spread further south because the frosts that kill them have declined.
Northland has become too warm for kiwifruit, central Otago is warm enough for grapes.
Weather patterns have changed. We have stronger westerly winds and it is becoming wetter in the west and drier in the east.
And it could get much drier, increasing the fire risk. Salinger pulls out a map that shows almost the whole North Island and half the South Island being a fire risk. Water will be limited for irrigation, possibly for drinking.
Some scientists say that if we don't act now in 50 years there will be irreversible damage.
David Wratt, a Wellington Niwa climatologist, who is on the bureau of the UN Intergovernmental Panel on Climate Change, says: "There are definitely risks, substantial risks."
Biodiversity
Matt McGlone is a scientist from Landcare Research and a bit of an optimist. He does not deny climate change, on the contrary. But he confesses he has been criticised for being "a little cheerful" about what it might mean for us.
A little bit warmer would be nice, people would flock here the way New Zealanders flock to Brisbane now.
For the world - well, that's a different matter. The Arctic Ocean is melting and land on which houses stand is being eroded by the sea. With another 1C temperature rise the whole boreal ecosystem of Greenland will begin pumping out methane.
In Europe, heatwaves have already killed thousands. And with global warming will come "mega-droughts" in the centre of continents. More death. This is an unacceptable price, McGlone says.
If he's a little cheerful in the New Zealand context, McGlone is "hand on heart" very worried about what will happen to our biodiversity.
There will be exotic invasive species.
They are already here but at the moment our indigenous flora has adapted to a cool climate and has an advantage. In a warmer climate new pests and weeds could thrive.
You can already see this with the spread of ants.
We have more than a dozen species of exotic ant and they are very temperature-sensitive. They are, says McGlone, the "stoats of the mini-world".
Argentine fire ants, for instance, are organised and hungry and have the potential to transform ecosystems.
There have been changes that might seem small but which have big consequences.
Beech trees seem to be seeding more frequently and abundantly, McGlone says. Rats and mice feed on these seeds and more rats and mice mean more stoats, which feed on them. Stoats also feed on native birds.
But we are not doomed, laughs McGlone. There is an easy solution.Technology. To get back to where we should be we will have to take carbon dioxide out of the atmosphere.
"People are talking about sequestration, stripping it out and pumping it into areas, and stripping it out at source."
The world's researchers need to get serious about this, he says. "When will they get serious? They'll get serious the moment anything really bad happens to the United States.
"It hasn't yet, but it will. They're a continent, it has to."
Bugs
Out in the field, says biologist Peter Maddison, there are signs of climate change. There is more coastal erosion - and rare organisms live on cliffs at risk - threatening plants such as Cook's scurvy grass.
Curious things are happening, he says. Plants are flowering out of season and some weeds are flowering right through the winter. Birds are nesting earlier. He saw baby mallards in the middle of July, when ducks don't normally start breeding until spring.
Maddison thinks there is evidence more pests are arriving. The Australian saltmarsh mosquito, which spreads Ross River fever, is here and is hard to get rid of.
The painted apple moth, which took intensive spraying campaigns to eliminate, probably would not have survived here 50 years ago. Nice cold winters inhibit some of the nasties.
You can see the effect with mangroves, Maddison says. A frost of -4C would usually kill seedlings but because we are getting fewer of those freezing days they are surviving and mangrove swamps are spreading. And a mystery fungus is killing kauri. A whole set of factors come together to stress plants. Climate change is one of them.
Stress makes plants more vulnerable. "The fungus is obviously killing them. But what has changed? That's the question you've got to ask. In the past 20 years what's changed? Global warming, that's what's changed."
White-tail spiders have increased. It might be natural, but warmth helps them. And the possibility of snakes establishing themselves here goes up with another degree of warming.
Henrik Moller, from Otago University's zoology department worries about our invertebrates - creatures such as beetles, moths, wetas, weevils and snails. Climate change could change the predator-prey interaction and put stress on ecosystems. It matters, Moller says. Biodiversity keeps life-cycles functioning.
It is vital for our food production, our agricultural systems - "think of things like pollinators and nitrogen-fixing animals and things that create soil".
There are health concerns, too. The Public Health Association warns of illness and death from malaria, dengue fever, injuries and heat stress, and more pollen and mould spores disrupting people's respiratory systems.
Agriculture
New Zealand's greenhouse-gas emissions profile is markedly different to those of other countries.
Along with carbon dioxide emissions from energy, cars exhausts and fossil fuels, we have the gnarly problem of 40 million sheep, 10 million cattle and a couple of million deer.
They belch (not fart) methane which is a far more damaging factor than CO2 in the mechanism of climate change, and they excrete nitrous oxide emissions through fecal matter and urine. Methane is 20 times more potent than CO2 - and nitrous oxide 300 times more potent.
Dr Harry Clark, from Agresearch, says there is no "near fix" for reducing methane emissions, but work on reducing nitrous oxide is progressing well.
He is certain a breakthrough will be made for methane emissions, perhaps by way of chemical intervention. It may be possible to develop a product, say a pill fed to the animal, which would selectively knock out organisms in an animal's digestive system and reduce the methane released.
Extreme weather could have an impact on how and where we farm. "Over time what climate change will do will alter the land use patterns, you'll be moving out of some enterprises, moving into others."
Jonathan Boston, a professor of public policy at Victoria University, is more apprehensive.
He says if we cannot find ways to reduce methane emissions and the world community decides to take collective action, New Zealand will have to make very substantial decreases in livestock numbers and move away from the kind of reliance we have at present on dairying and meat and wool production.
Boston has young children. Even if the world takes the action required to avert catastrophic global warming, the way they live in less than 50 years will still be very different.
"It seems very likely we will be driving very different kinds of cars, that we'll be relying on potentially different modes of transport.
"We may well be eating a different combination of foods, and it may well be that the structure of the agricultural sector is rather different."
Security
We cannot take ourselves out of the global context.
The retreat of glaciers in other parts of the world has huge consequences for river flows, including the major rivers of Asia, Latin America, parts of North America and parts of Europe.
Reduced water has big implications for agriculture, domestic consumption - and stability. Already many cities in China are short of water.
"The implications for New Zealand are potentially a significant increase in environmental refugees wanting to find other places to live, says Boston "There are major implications for world food production with consequences for the price and availability of food: political instability in countries which are currently stable ... potential increases in military conflicts, civil war as people take to military means to fight for scarce water resources."
None of this is far-fetched, Boston says: "This is a perfectly realistic possibility that military planners in many countries are already focused on."
The Lowry Institute, an Australian think-tank, is worried about security issues for that country. A report it commissioned concludes that the wider security implications of climate change have been seriously underestimated.
Extreme weather patterns could lead to unregulated population movements in Asia and the Pacific. And, for a handful of low-lying Pacific nations, climate change is the ultimate security threat because their countries could become uninhabitable.
"Far from exaggerating the impact of climate change it is possible that scientists may have underestimated the threat," the authors say. They recommend the emerging security challenge should be a focus for the intelligence community.
Oceans
There is a problem brewing in the world's oceans. We're not even talking about the consequences of warmer temperatures. The ocean is a big sink for the carbon dioxide which we put into the atmosphere, says Cliff Law, a principal scientist with Niwa's ocean-atmosphere group.
About a third to a half of all the CO2 we have ever released has been taken into the sea and a "neat little buffering system" against carbon dioxide has been quietly protecting oceans for thousands of years.
But since humans started putting a lot more carbon dioxide into the air - and consequently into the sea - the buffering system has started to fail.
The prediction is that the acidity of the ocean will have increased by 300 per cent in 100 years.
Scientists don't know for sure what will happen, but organisms such as shellfish and coral consist mainly of calcium carbonate and the fear is they will not be able to build their shells or skeletons in a more more acidic, corrosive marine system.
We should all care, says Law. Fish are at the top of the food chain and organisms such as shellfish are near the base. No one knows what will happen to the food chain if calcifying organisms do not survive.
New Zealand may be better off in some ways from climate change, but not so with ocean acidification.
A lot of our ocean is cold water and it is harder for these organisms to produce shell in colder water:.
"When you get down to the Southern Ocean where the water is very cold, you have these huge productive areas, big food chains going down there that support whales and large fish, and at the base you have some calcifying organisms.
"Can these organisms adapt or are they just going to die out? Will they be replaced by something else, or will the food chain collapse above them?"
With a warming ocean and overfishing, marine life is getting hammered. It's scary, "particularly when you put all the things together. It's hard to imagine that you've got this huge ocean out there that's covering 70 per cent of the world and is about four kilometres deep but it's basically reaching the level where it can't cope any more."
Are we doomed?
For God's sake don't print that, says Law. No, we're not doomed, he says.
But all the indicators are telling us there is no more time for dithering. We need to do something. Now.
