New technologies will help reduce agricultural greenhouse gas emissions but, for now, efficiencies remain key
17 July 2019
Within the next 5–10 years, it’s likely New Zealand’s livestock farmers will be able to employ selective breeding,
methane inhibitors and perhaps even methanogen vaccines to help reduce their greenhouse gas emissions. In the meantime,
farmers wanting to make a difference need to know what their emissions are and where they come from, so they can examine
every facet of their business for efficiency improvements that can maintain profitability while reducing emissions.
That’s the message from Dr Harry Clark, Director of the New Zealand Greenhouse Gas Research Centre (NZAGRC) and a member
of the Interim Climate Change Committee (ICCC), following the launch today of a new website (www.farmingmatters.nz
) by NZAGRC, aimed at equipping New Zealand farmers and rural professionals with the knowledge they need to assess and
manage on-farm emissions, and adapt to a changing environment.
Dr Clark says the launch of the website is timely in light of the Government’s signal yesterday that it will implement
farm-level accounting and pricing of agricultural greenhouse gas emissions by 2025.
The site initially focuses on methane, which makes up 70% of New Zealand’s agricultural emissions, but will soon expand
to include information on nitrous oxide, another significant agricultural greenhouse gas, as well as strategies for
adapting to climate change.
“Methane belched out by ruminant livestock such as cows and sheep is a problem for New Zealand,” Dr Clark says. “While
methane breaks down in the atmosphere a lot faster than other greenhouse gases such as carbon dioxide, every tonne
emitted is 28–34 times more effective at trapping heat than a tonne of carbon dioxide, over the first hundred years
after an emission occurs.
“Researchers here and overseas are therefore investigating a number of technologies that might help to reduce methane
emissions by livestock in the future.”
Some animals emit less methane per unit of feed eaten than others, thanks to a smaller rumen (fore-stomach) with a
distinctive population of micro-organisms. Breeding for this trait could result in a potential emissions reduction of
3–8% over 20 years. This research is well advanced in sheep, while work in cattle is just starting, Dr Clark says.
Methanogen vaccines and inhibitors are also under development. Vaccines are being tested in the laboratory, with the
goal of reducing methane emissions by 30%. An inhibitor has already been developed in the Netherlands that demonstrably
reduces emissions by at least 30%. However, in its current formulation, it must be included in every mouthful of feed –
less than ideal for New Zealand’s pasture-based livestock. New formulations and alternative products are being
But until such technologies are available, Dr Clark encourages farmers wanting to further reduce their emissions to keep
looking for small improvements in every aspect of their operation. He says efficiency gains already achieved across the
sector mean that New Zealand’s total agricultural greenhouse gas emissions are no longer going up.
“Not all farms have the same potential to further reduce emissions,” he adds. “Some farmers have already done what they
can. Others are limited by their unique climate, topography, markets and infrastructure. But there are a number of steps
they might like to consider – and every small step is a step in the right direction.”
These could include getting more production from pasture to reduce reliance on imported feeds, trialling alternative
forage crops, reducing animal numbers but increasing productivity per animal, achieving greater longevity in the
breeding herd or flock, and applying nitrogen fertiliser using precision technologies.
Dr Clark says there’s no one-size-fits all solution, and individual farmers are in the best position to figure out how
they might be able to reduce their emissions without compromising profitability – particularly as the framework for
managing farm-level emissions takes shape over the coming years.
The new Farming Matters website aims to help by addressing some of the existing myths and misunderstandings about
agricultural greenhouse gases and climate change and communicating the very latest advances in emissions-reduction
technologies and practices. The site uses short videos and simple graphics to help explain the science and associated
“Ultimately, New Zealand’s emissions-reduction targets and ongoing response to climate change will be the outcome of a
range of complex interacting factors, not just science and technology,” Dr Clark adds. “Our goal with Farming Matters is
to ensure farmers have the information they need to weigh up their options and take steps towards reducing farm-level
greenhouse gas emissions.”
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