Understanding & mitigating greenhouse gas emissions
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| Tony McSeveny measuring greenhouse gas exchange in mature kānuka. Image - John Hunt |
Many people have argued about the cost-effectiveness of the Kyoto Protocol, but few argue against the reality of mankind'scontribution to increasing concentrations of greenhouse gases in the atmosphere, and the dangers this presents to our economy and our quality of life. Global warming is potentially the greatest threat facing the world over the next decades. Science has a key role in developing mitigation strategies.
To offset future liabilities and risks, New Zealand must reduce its We are also developing remote sensing techniques, using aircraft-net greenhouse gas emissions. Hence our science is focused on or satellite-imagery, to assess carbon stored in forests. Together, re?ning estimates of emissions and stored carbon so that we have these projects improve the accuracy of systems for estimating more accurate understanding of potential climate change threats, stored carbon and how much this needs to increase by to mitigate and more information in support of two key mitigation strategies: the greenhouse gas emissions that New Zealand cannot reduce by other means.
- Increasing carbon stored in forests and soils; and
- Reducing emissions, especially of carbon dioxide (CO2) from fossil fuel use, and methane and nitrous oxide gases from agriculture.
One tonne of methane has the same atmospheric warming potential as 21 tonnes of CO2; one tonne of nitrous oxide is equivalent to an astonishing 310 tonnes of CO2.
New Zealand's large numbers of ruminant sheep and cattle are responsible for the unusually high methane component of our greenhouse gas emissions. Directly measuring emissions from a whole paddock full of sheep or cows is not easy but Manaaki Whenua and colleagues from the University of Edmonton, Canada, have now developed some innovative techniques for doing just that. Better quality measurements will give more con?dence to national-scale estimates and enable researchers to quantify the impact of methane-reducing technologies in agriculture, if and when these become available.
This year, we demonstrated the mechanism by which New Zealand soils under both indigenous and planted exotic forests absorb and deactivate methane-an exciting discovery as increasing the amount of land under forest could have significant potential for offsetting methane emissions as well as CO2 emissions.
Agricultural soils and effuents are the main sources of nitrous oxide, an extremely powerful greenhouse and ozone-depleting gas. We produced the first regional maps of nitrous oxide emissions, based on a New Zealand version of a robust predictive model in wide use globally. These maps are a step towards producing the all-important national map. Concurrently with the inventory work, Manaaki Whenua scientists, with AgResearch Tony McSeveny measuring greenhouse gas exchange in mature kānuka. and industry organisations, have been progressing research on soil treatments to interrupt the formation of nitrous oxide, as this could have a disproportionately large impact on mitigation efforts.
Manaaki Whenua, Scion (formerly Forest Research) and Wildlands Research are now four years into a five-year cycle of measuring the carbon stored in 1400 permanent field plots of indigenous forest and scrub throughout New Zealand. A similar programme is underway in planted forests, and other research is refining an internationally recognised soil carbon monitoring system.
We are also developing remote sensing techniques, using aircraftor satellite-imagery, to assess carbon stored in forests. Together, these projects improve the accuracy of systems for estimating stored carbon and how much this needs to increase by to mitigate the greenhouse gas emissions that New Zealand cannot reduce by other means.
| New Zealand emissions* | Global emissions |
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* New Zealand’s greenhouse gas inventory 1990–2003, MfE, April 2005.
Compared to the rest of the world, New Zealand has a higher proportion of nitrous oxide and significantly higher proportion of methane in our emissions.
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Talk to us |
Richard Gordon
Email 
Ph (03) 325 6700 |
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On our website |
| Greenhouse Gases & Carbon Sinks | |
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Funding |
| FRST |