New Zealand has signed up to a number of international conventions and protocols that commit us to doing our bit to reduce greenhouse gas (GHG) emissions, with reduction targets we must meet by certain points in the future. These GHG targets include all gasses and all sectors, including agriculture.

What does this mean for the dairy industry?

• In New Zealand, half of our emissions come from agriculture, and nearly a quarter come from dairy biological emissions (i.e. nitrous oxide and methane).
• To meet New Zealand’s GHG targets and transition successfully to a low-emissions economy, the dairy industry needs to take action.
• New Zealand is investing in the development of technological solutions that will reduce biological emissions but these solutions are some time away from being available to farmers.
• In the meantime, there is action that farmers can take, and may already be taking, to reduce on-farm GHGs.

What does this mean for farmers?

• 85% of the dairy sector's emissions are generated on farm.
• Exact GHG reduction targets haven't yet been set for the dairy industry, but we know a reduction will be required, so it's important farmers know what they can do to reduce on-farm GHGs now.

What can farmers do?

Know your own GHG number

There are a number of tools available which can estimate your farms current GHG footprint. These include Overseer or the Lincoln University Greenhouse Gas calculator which provide a rough estimate.

Know where your GHGs are coming from

The main agricultural GHGs are methane (CH₄) and nitrous oxide (N₂O). Methane is produced by ruminants (e.g. cows and sheep) by methanogen microbes that are naturally present in the rumen. Most methane is emitted when cattle burp. The amount of methane produced for each farm is directly related to the total feed intake for that farm (including cows, heifers and calves).

Nitrous oxide is emitted from soil when urine, faeces and fertilisers are broken down by microbes in the soil.

HOW METHANE (CH₄) IS PRODUCED

HOW NITROUS OXIDE (N₂O) IS PRODUCED

Know how to reduce your emissions

Optimising your farm’s efficiency will help reduce your biological emissions.

Methane

A key driver of methane emissions is total feed intake on farm. This can be reduced in a profitable manner by:

• Only use supplements when they fill a true feed deficit and produce a profitable response. See the Feedright section.
• Improve cow reproduction, health and longevity to minimise cow wastage and reduce rearing of non-productive stock (e.g. replacement heifers). For more, see the InCalf programme and Pillars of a new dairy system research project.

Nitrous Oxide 

A key driver of nitrous oxide emissions is nitrogen surplus. This can be managed in a profitable manner by:

• Reduce nitrogen inputs on-farm
  • Optimise amount, timing, and placement of nitrogen fertilisers
  • Manage effluent effectively and treat as a fertiliser
  • Optimise pasture management
• Use appropriate infrastructure to manage N outputs
• Only use supplements when they fill a true feed deficit and produce a profitable response. See the Feedright section.
• Improve cow reproduction, health and longevity to minimise cow wastage and reduce rearing of non-productive stock (e.g. replacement heifers). For more, see the InCalf programme and Pillars of a new dairy system research project.

See also Mitigation options.

Frequently asked questions

• What is the difference between short and long-lived gases?

  Not all greenhouse gases have the same warming effect or stay in the atmosphere for the same amount of time.

  Carbon dioxide and nitrous oxide are long-lived gases (that build up in the atmosphere for hundreds to thousands of years) while methane only remains in the atmosphere for a relatively short period of time (about 12 years) but is 25 times more potent at warming the planet than carbon dioxide.

  Because methane doesn’t build up, scientists have advised that it does not need to be reduced to zero in order to avoid warming the atmosphere further. By stabilising methane at a reduced level (between 10-22% below current levels), we can make the equivalent contribution as net-zero for long-lived gases.

• What proportion of greenhouse gas emissions are coming from agriculture and how are they produced?

  Agricultural emissions (methane and nitrous oxide) comprise 48% of New Zealand’s total emissions. Dairy emissions make up nearly half of agricultural emissions, and therefore almost a quarter of all emissions.

  Methane is the main biological gas (80%), and is released when ruminant animals burp. Nitrous oxide (20%) comes from the urine and dung of these animals, as well as from fertiliser use.

• How have biological emissions from agriculture tracked over time?

  Between 1990 and 2017, agricultural emissions increased by 13.5% and have been relatively stable since 2005. Methane alone has increased by only 4.4% since 2019. For comparison, carbon dioxide emissions from Energy (including transport, manufacturing, and electricity) have increased by about 38% since 1990.

  

• Are there technological solutions for agricultural emissions on the horizon?

  Both the Government and the agricultural sector, including dairy farmers via the milk solids levy, is investing in technological solutions to address our biological emissions through the Pastoral Greenhouse Gas Research Consortium.

  It was set up in 2003 and receives industry investment of $5 million per year. With continued support and investment, we are confident tools will be developed to help us significantly reduce emissions from New Zealand’s pasture-grazed livestock.

  We’re already seeing promising results already into the development of inhibitors, vaccines, and other technological solutions. The development of these solutions will make us well placed to become a world leader in climate change action.

• New Zealand’s emissions are so small compared to other countries, will any of our efforts help prevent climate change?

  While New Zealand’s share of greenhouse gas emissions globally is less than 0.2%, small emitters like us make up 24% of the worlds emissions. Together we can make a big difference.

  In addition, all countries have signed up to the Paris Agreement committing them to reducing their emissions. The agreement relies on everyone playing their part. It would be a huge reputational and trade risk for New Zealand if we didn’t make an effort to reduce our emissions profile.

• Why is New Zealand considering agricultural emissions when the rest of the world is focused on carbon emitting sectors?

  Over 100 countries have included agriculture within their emissions targets under the Paris Agreement.

  They will have to address their agricultural emissions at some point. Right now many countries are preoccupied with reducing carbon dioxide emissions.

  But as their carbon dioxide emissions decrease the proportion of their emissions coming from agriculture will increase.

  Over time they will look to New Zealand for leadership on how best to reduce their agricultural emissions.

• Does ‘net carbon emissions’ include the carbon that is captured in the soil?

  Soils store significantly more carbon than trees and plants together. While at a national scale New Zealand soils have higher soil carbon levels than the world average, there appears to be little change in overall levels over time.

  It is also difficult to monitor and measure carbon in soil at a national level. It takes a long time to build up but is lost very quickly through poor land management practices, wind erosion and droughts.

  The loss of carbon in soil effects our greenhouse gas emissions. This suggests there is limited potential for significant carbon sequestration from New Zealand’s soils.

• Does ‘net carbon emissions’ include the carbon that is captured in growing grass?

  No, carbon dioxide (C02) is absorbed from the atmosphere by grass in the process of photosynthesis. Carbon dioxide leaves the system again through respiration and decaying grass. 

• Is methane “carbon neutral”?

  All carbon dioxide absorbed into grass and eaten by grazing animals eventually returns as carbon dioxide to the atmosphere and is therefore part of a closed Carbon Cycle. However, it is the conversion of some of the ingested carbon into methane that causes the challenge.

  Although methane only remains in the atmosphere for a relatively short period of time, it is 25 times more potent at warming the planet than carbon dioxide. This is above and beyond the warming which would have otherwise been caused by carbon dioxide alone, and thus methane emissions cannot be considered carbon neutral.

  

• Can on-farm planting be recognised by the Government as on offset?

  Many dairy farmers are small forestry block owners, but many more are already plant for shelter, fodder, and to improve water quality and biodiversity or to retire land.

  Farmers should be recognized for all planting, and be able to offset their emissions at the farm-gate. We would like to work with the Government as the policy mechanism is developed for agricultural emissions.

• Will efforts to address water quality help reduce emissions?

  Many farmers across the country are already thinking about environmental sustainability in a broader sense and putting this into action on their farms.

  Much of the work farmers have underway to improve water quality also has the co-benefits of improving their greenhouse gas emissions profile and biodiversity.

  We know that increased on-farm planting has positive effects for soil, air, and water quality –  therefore these environmental issues all need to be treated together.

• What is dairy industry’s economic contribution to New Zealand?

  Dairy farming is the fifth largest industry in New Zealand, and accounts for $8.2 billion (or 3.1%) of our total Gross Domestic Product (GDP). The dairy industry employs about 46,000 people, and is the largest export sector. Of the product produced, approximately 95% is exported around the world, earning $17.2 billion in export revenue. It is estimated that for every dollar spent by dairy farmers, an additional $0.98 of value add is created across the country.