Climate change specialists say New Zealand would face environmental challenges if the danger of methane gas is revised. Photo / Supplied
New Zealand might be making a bigger contribution towards global warming than scientists thought.
A NASA study says climate scientists have underestimated by 20 - 40 % how much methane warms the planet - even though it is already supposed to be 25 times more potent than carbon dioxide (CO2).
The study, led by NASA's Goddard Institute for Space Studies in New York, added methane blocked the making of aerosols that would otherwise cool the planet - a new finding not counted in present estimates of global warming.
New Zealand is almost unique in the developed world because of its great proportion of methane emissions. The gas is released by farm animals, landfills, crops and coal mines.
New Zealand scientists reacted cautiously to the new study, saying lots of work was needed to back it up.
A New Zealand author் of the newest report of the Intergovernmental Panel on Climate Change, Martin Manning, said at least one more study showing the similar thing would be required before the panel would change its stance.
It was a "very short paper on a very complex topic" but it would open up debate, he added.
Pastoral Greenhouse Gas Research Consortium manager Mark Aspin added New Zealand would be look forward to the IPCC for guidance, "given our [emissions] profile it is something we want to keep an eye on".
The study found that methane and another pollutant, carbon monoxide, soaked up an atmospheric "scrubber" called hydroxyl that would otherwise unite other substances to make cooling aerosols. The sulphate aerosols elbowed to one side by methane cooled the earth by scattering light also affecting the clouds.
Standard estimates covering the next 100 years says that each tonnes of methane will have 25 times the global warming effect of a tonnes of carbon dioxide.
However methane's effects are short-lived compared with CO2, so the shorter the term, the larger weight methane is given in the equation.
Sustainability Council executive director Simon Terry, a climate change analyst and lobbyist, said New Zealand would not necessarily have to increase its emissions cuts if the study was right.
However if methane's potency was officially increased, it could affect the "exchange rate" for people wanting to offset methane emissions by carbon dioxide sinks.
That meant more carbon dioxide would have to be cut or stored in forests and elsewhere to offset each unit of methane, he added.
The study found methane also had a useful effect.
The cooling aerosols it blocked were coupled to acid rain and breathing problems.
In an article published on the Goddard Institute's website, the study's lead author added climate treaties such as the Kyoto Protocol underestimated the effect of methane along with carbon monoxide because they measured greenhouse gases as soon as they reached the atmosphere.
The institute study was a better measure, he added, because it looked at greenhouse gas emitted at the earth's surface.
A NASA study says climate scientists have underestimated by 20 - 40 % how much methane warms the planet - even though it is already supposed to be 25 times more potent than carbon dioxide (CO2).
The study, led by NASA's Goddard Institute for Space Studies in New York, added methane blocked the making of aerosols that would otherwise cool the planet - a new finding not counted in present estimates of global warming.
New Zealand is almost unique in the developed world because of its great proportion of methane emissions. The gas is released by farm animals, landfills, crops and coal mines.
New Zealand scientists reacted cautiously to the new study, saying lots of work was needed to back it up.
A New Zealand author் of the newest report of the Intergovernmental Panel on Climate Change, Martin Manning, said at least one more study showing the similar thing would be required before the panel would change its stance.
It was a "very short paper on a very complex topic" but it would open up debate, he added.
Pastoral Greenhouse Gas Research Consortium manager Mark Aspin added New Zealand would be look forward to the IPCC for guidance, "given our [emissions] profile it is something we want to keep an eye on".
The study found that methane and another pollutant, carbon monoxide, soaked up an atmospheric "scrubber" called hydroxyl that would otherwise unite other substances to make cooling aerosols. The sulphate aerosols elbowed to one side by methane cooled the earth by scattering light also affecting the clouds.
Standard estimates covering the next 100 years says that each tonnes of methane will have 25 times the global warming effect of a tonnes of carbon dioxide.
However methane's effects are short-lived compared with CO2, so the shorter the term, the larger weight methane is given in the equation.
Sustainability Council executive director Simon Terry, a climate change analyst and lobbyist, said New Zealand would not necessarily have to increase its emissions cuts if the study was right.
However if methane's potency was officially increased, it could affect the "exchange rate" for people wanting to offset methane emissions by carbon dioxide sinks.
That meant more carbon dioxide would have to be cut or stored in forests and elsewhere to offset each unit of methane, he added.
The study found methane also had a useful effect.
The cooling aerosols it blocked were coupled to acid rain and breathing problems.
In an article published on the Goddard Institute's website, the study's lead author added climate treaties such as the Kyoto Protocol underestimated the effect of methane along with carbon monoxide because they measured greenhouse gases as soon as they reached the atmosphere.
The institute study was a better measure, he added, because it looked at greenhouse gas emitted at the earth's surface.
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