KEY POINTS:
Satellite images of greenhouse gas clouds over New Zealand suggests methane from livestock may not be as big a problem as first thought.
And the New Zealanders who found the satellite discrepancy believe that if their theory proves true, the find could have major implications on taxpayers and the country's Kyoto responsibilities.
The cost of meeting obligations under the Kyoto climate change treaty falls entirely on taxpayers.
The Treasury's estimate of the bill is just shy of $600 million for the period between 2008 and 2012.
Allan Mountain and Christoph Kwintkiewicz of the Mt Maunganui-based energy consultants Key Energy believe the research from Germany's Bremen University may dramatically change the status of methane emissions from New Zealand animals.
But the National Institute of Water and Atmospheric Research (Niwa) says New Zealand emits too little to be detected from space, and monitoring since 1989 has shown methane levels growing.
Methane is nine times more potent than carbon dioxide in its ability to trap heat.
Using measurements from a space sensor, the researchers at Bremen produced maps of greenhouse gas clouds hovering over the world based on readings between 2003 and 2005.
The data indicated no detectable increase in methane over New Zealand, in contrast to the rest of the world.
"There was nothing," said Mr Kwintkiewicz. "You couldn't really see the difference between the sea around us and New Zealand, which shouldn't actually happen."
But New Zealand's carbon dioxide emissions kept pace with the rest of the world.
Mr Mountain said one possibility could be that the emissions were below the satellite sensor resolution, having been dispersed by the wind before it could be measured.
But another explanation was that due to the country's unique geography, high UV radiation exposure and moisture content, methane is broken down (oxidised) faster than elsewhere in the world.
"All we're suggesting is that we want to put this in the public domain because we think if the science can be validated, it's of huge benefit to us all here in New Zealand.
"What we're suggesting is that Government stumps up some money for the scientific research to be done, and it can be then discounted completely, or if it is the case as we hope ... it's going to be a huge reduction in our exposure to Kyoto and we'll have a little more money in the bank."
Niwa scientist Keith Lassey said New Zealand emitted relatively small levels of methane compared to the rest of the world - too little to be picked up by the space sensor.
The lack of a methane cloud is a curiosity, but Dr Lassey said he and a colleague had looked at the issue two years ago and deduced that in order to be able to measure the country's emission from space, the instrument would need a 1 per cent level of precision.
"Even though we have a little intense plume, by the time it's left New Zealand there isn't much to see."
New Zealand, meanwhile, has massive fluxes of carbon dioxide moving from the atmosphere to sinks such as vegetation and oceans, and vice versa. "Even small changes in those can appear to be a big cloud."
Dr Lassey said Niwa had been monitoring methane levels on the ground since 1989 and had seen them grow.
"We know what levels are in the atmosphere on average. What we haven't been able to do is look for the evidence of the methane cloud coming off New Zealand. We're not well positioned to do that here ... It's beyond any funding we've got to do that."
Higher concentrations of UV rays over New Zealand were unlikely to accelerate the breakdown of methane.
"The methane molecule's a pretty stable beast. They're not broken down at all easily."
UV rays indirectly oxidise methane by creating an OH radical, "the detergent of the atmosphere", which breaks down gaseous nasties like carbon monoxide and methane.
"But methane's so resistant that, on average a methane molecule that you put into the atmosphere will stay in the atmosphere for about 10 years before it gets gobbled up that way," said Dr Lassey.
He agreed with Mr Mountain's call for research funding.
"It's such a curiosity, and methane from New Zealand is potentially so expensive in terms of our Kyoto commitments, that it would be worth clearing the issue up."
Climate Change Minister David Parker said his officials would examine Key Energy's information if it was sent to his office.
GAS THAT CAUSES WORLD WARMING
What's wrong with methane gas?
It traps the sun's rays in the Earth's atmosphere, which heats up the world.
Isn't carbon dioxide the main problem?
It is in most countries. But methane is nine times as bad and in New Zealand our belching sheep and cows produce a lot of it.
Maybe not as much as we thought?
Perhaps. A German study suggests our methane emissions cannot be detected from space.
How does that help us?
If the findings are confirmed it could save us all money. Under the Kyoto agreement New Zealand faces a $600 million bill over the next four years.
