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24.04.15 Reducing New Zealand's greenhouse gas emissions

24th Apr 2015

The emissions intensity of New Zealand agriculture (the measure of the GHG’s generated per unit of meat or milk produced on-farms) has declined on average by about 1% per year since at least 1990. This has happened because farms have become more efficient through employing techniques such as improved animal genetics, management and better grassland management and feeding practices over the past 20 years.

On the flip side of this however, the reduced emissions intensity has been more than offset by the increased overall product generated by the sector. As such the emissions from New Zealand agriculture have risen by 15%, (although without the efficiency gains this would be much higher, about 30%). So while farmer’s efficiency gains are addressing a large proportion of the problem, they are not enough to counter the extra greenhouse gases being produced overall.

What’s the solution?

Although the drive for efficiency on-farm provides part of the solution, and by continuing to improve efficiencies, New Zealand farmers will continue to reduce the intensity of emissions (per unit of prouduct), in order to stop the total emissions from rising there is a need for practical and cost-effective tools to reduce emissions and achieve economic growth targets.

What are the research priorities?

The priorities that are being investigated in New Zealand are described below.


Low methane animals – methane emissions vary between animals. The level of emission is a genetically heritable trait, so it can be included in a selection index. Lower emissions appear not to affect other production traits so selecting for lower methane emissions would not impact negatively on a farm’s production

Low methane feeds – some feeds help reduce methane emissions and increase nitrogen utilisation. Identifying and confirming these feeds will mean recommended feeding regimes can be developed based on current and new feed options for use in different farm systems.

Methane vaccine – scientists are working on a vaccine programme which could reduce emission by up to 20% without reducing productivity. The vaccine stimulates antibodies to counter key methane-generating microbes within the rumen in livestock.

Methane inhibitors – Inhibitors can knock out methane – generating microbes. Researchers are looking for substances that work in the rumen without side-effects across a range of microbes. Successful inhibitors could be delivered in feed, a bolus or drench, mineral lick or within the water supply.

Reduce nitrous oxide and nitrate leaching – research is looking at novel interventions and on-farm management guidelines that reduce nitrate leaching and nitrous oxide emissions.

Increasing soil carbon – increasing carbon in the soil could offset greenhouse gas emissions. Research is looking at soil carbon levels across New Zealand and techniques to verify changes in carbon content. Work is also exploring management practices that increase carbon sinks.

What are farmers doing now?

At this point the biggest impact on greenhouse gas emissions intensity comes from New Zealand farmers continuing to increase the efficiency of their operations as much as possible. The research highlighted above is the crucial next step as these additional tools are needed soon.

Source: Pastoral Greenhouse Gas Research Consortium, New Zealand.