Committed to the Kyoto Protocol, New Zealand promised to cut its emissions to 1990 levels. The country's biggest source is methane from cattle, and as Stephen Evans discovers, the issue is raising a stink among local farmers.
Frank Brenmuhl is a bluff New Zealand farmer who could talk the hindlegs off a donkey and, more to the point, off a politician proposing to tax the gas that comes out of his cows.
New Zealand's climate means sheep and cows can graze outdoors all year
Mr Brenmuhl has just turned 60 and he has been a dairy farmer on the west coast of the South Island of New Zealand since he was 29.
He worked his way up from farm labourer to farm manager to farm owner, five generations after his great-great-grandfather fled as far as he possibly could from the politics of Poland and Germany in the 1870s.
Now, Frank has encountered a different sort of politics: the environmental politics of New Zealand. And he is not happy about it.
So much so that he now spends much of his time away from the farm, lobbying in Wellington on behalf of the country's dairy farmers.
There has been much to lobby about.
First, the New Zealand government came up with the idea of putting a levy on the global-warming emissions of sheep and cows.
Could a vaccine reduce the amount of methane sheep and cows produce?
These ruminant animals, as they are called, these hoofed beasts which chew the cud in the various compartments of their stomachs - produce methane which they then emit.
And this methane is by far the biggest global warming polluter in New Zealand, about half the total, in fact, there being little manufacturing to speak of.
And New Zealand, seeing itself as a good global citizen, committed itself to reduce its global warming emissions to 1990 levels.
Hence the levy, or "tax" as farmers like Frank immediately called it. In fact, a "Fart tax" - Fart, standing of course, for the Fight Against Ridiculous Taxes. This is a handy acronym for the bumper stickers that were soon as numerous as, well...as ruminant animals in New Zealand.
Partly funded by farmers, research is now going on into whether a vaccine might stop cows and sheep passing wind
With this powerful publicity campaign, farmers led by Frank Brenmuhl saw off the tax in return for promising to put up money for research into how to stop cows and sheep belching. I suppose in the interests of accuracy, I should tell you that 95% of the methane emerges from the front end.
The so-called "Fart tax" was a bit of a rhetorical device, a bit of poetical - or at least political - licence.
So, partly funded by farmers, research is now going on into whether a vaccine might stop cows and sheep passing wind.
To this end, the genome, the exact genetic make-up, of microbes in the ruminants' stomachs has been mapped in a lab on the North Island.
Scientists are also identifying cows which burp less, with a view to breeding these low emitters to produce calves which burp less.
If science does not come to the rescue, the other possibility is just having fewer cows and sheep. And this, you may imagine, is causing much chatter in the shed meetings that New Zealand farmers hold.
Shed meetings are a delightful concept.
Farmers gather in a cattle shed, usually with cases of beer or, more likely in my experience, with fine local wine.
They argue and gossip in the stark electric light, their voices echoing into the serene rural silence of a black New Zealand sky, speckled with the sparkle of the southern stars.
Farmers have been calculating the pluses and minuses of New Zealand's emissions trading scheme. Polluters, like the owners of ruminant methane expellers, pay. Those who, say, plant trees that soak up carbon dioxide, get money back.
In the great global warming debate, much of the attention has been on industrialised countries, but it is relatively easy to cut emissions in a factory, let us say, or an office
Frank reckons that cutting the herd from the typical 350 cows to 275, and then planting a quarter of the farm with trees - all to meet the Kyoto commitment - would mean running the farm at a loss.
Farmers think much of this is crazy.
And it is true that if you wanted to find the ideal place on this planet for grazing cows to produce milk, it would be New Zealand.
Cattle can stay out on abundant grass for 12 months of the year.
In harsher climates for dairying, farmers use what is called cut and carry - cut the grass and carry it to the cattle in sheds in winter.
As farmer Frank Brenmuhl says of any plan that involves fewer cows and sheep: "It does not make sense.
We know that the world needs food production. We are very good at it".
There is a wider issue here.
In the great global warming debate, much of the attention has been on industrialised countries, but it is relatively easy to cut emissions in a factory, let us say, or an office.
New materials emerge. Technology helps. People organise themselves differently with relatively little pain.
But for countries with large populations of ruminant emitters of global warming gases - like New Zealand, but also Brazil, Argentina, Ireland, Australia, Latvia - what is the answer? Perhaps they should think of a tax - but what to call it?
From Our Own Correspondent was broadcast on Thursday, 2 October, 2008 at 1100 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.