Weather1 always brings challenges for the farming community, but climate change2 has the potential to create additional risks. The dairy and agricultural sectors produce about half of Aotearoa3 New Zealand’s greenhouse gas4 emissions, and they are working on ways to reduce them.
Dairy – a significant part of Aotearoa New Zealand’s economy
Farming is a way of life in Aotearoa New Zealand, and it has shaped who we are as a nation. Our moderate climate5 and reliable rainfall have enabled good growing conditions6. This is one of the few places in the world where cows can graze on pasture year round.
The dairy sector contributes over $19 billion dollars to Aotearoa New Zealand’s economy. In 2019, New Zealand was the main exporter of milk and milk products worldwide. Not all milk products go overseas – Kiwis have one of the highest rates of domestic milk consumption in the world!
Primary industries7 like dairying require unique sets of environmental conditions for optimum8 production. If these conditions are disrupted by climate change9, the dairy producers and the communities that support them and who they support will also be impacted.
Farmers are at the mercy of the weather, so if climate change is making things more unpredictable, that makes it harder for farmers to plan and prepare.
Ben Fisher, Farm Manager, Scott Farm
Risks posed by climate change
Perhaps the biggest risk for dairy farming is the increased severity of extreme weather events. The right amount of rainfall – at the right times – is important for optimal pasture management.
Too much rain can cause a variety of problems such as:
- loss of soil to erosion10
- increased sediment11 in waterways
- loss of soil structure12 due to pugging
- increased nitrous oxide13 emissions from saturated soils
- damage to infrastructure14 such as fences, bridges and roads.
Not enough rainfall over a period of time can cause drought conditions, which can impact pasture growth and reduce the amount and quality of feed. Farmers need to buy supplemental feed to keep milk production going or dry off (stop milking) stock earlier than planned.
Animal welfare may also be impacted by climate change15. Much of the country’s livestock lives outdoors so they risk exposure to extreme weather and/or rising temperatures. Farmers may need to build infrastructure to house animals when necessary or select breeds that better suit the changing conditions.
Pasture plant species16 are also suited to particular conditions. Changes in temperature17 and rainfall may require new forage18 cultivars. Changes may even make some land unsuitable for dairy farming.
There are biosecurity19 risks associated with climate change. Warmer temperatures may allow new exotic pests, weeds and diseases20 to become established.
Impacts of dairy farming on climate change
Nearly half of New Zealand’s greenhouse gases21 come from agriculture. The main gases22 are methane23 and nitrous oxide. Methane is produced by ruminant animals24 and emitted mostly as burps. Methane production is split about evenly between the dairy sector and the beef and sheep sectors. Nitrous oxide is produced by soil microbes that transform25 nitrogen26 from urine, dung and fertiliser27 into a gas.
The dairy sector recognises that climate change is a global issue and, like any large industry, it has to play its part in reducing emissions. Scientists and farmers are involved in a wide range of research to investigate alternative forages, animal breeding and on-farm management options to reduce methane and nitrous oxide emissions.
The dairy sector and other primary producers have committed to work with the New Zealand government and iwi/Māori to reduce agricultural greenhouse gas emissions at farm level. Read about this and other initiatives in the article The primary sector and climate change.
Nature of science
Scientific developments are influenced by societal needs. Agricultural sectors are contributing to research on greenhouse gas reductions through improved plant and animal breeding and via changes to farm management practices.
Activity ideas
Investigate long-term average annual temperature and annual precipitation28 data29 for 30 sites from Kerikeri to Invercargill to view variations over time with the activity Using weather data.
Using infographics challenges students to delve into infographics and how they present science information related to climate change.
Useful links
Find out about agricultural greenhouse gases on the DairyNZ website.
Read about climate change and agriculture On NIWA's website in the Science topics for students section.
Low-emission feeds have the potential to reduce methane and nitrous oxide30 emissions.
Acknowledgement
This resource has been produced with the support of DairyNZ.
- weather: Daily or short-term conditions like temperature, cloud cover, precipitation and wind affecting a certain area.
- climate change: The large-scale, long-term increase in the Earth’s average temperatures, with associated changes in weather patterns. There is significant scientific evidence that warming is due to increased quantities of greenhouse gases in the atmosphere, with most of the rise due to human activity.
- Aotearoa: The Māori name for New Zealand, meaning Land of the Long White Cloud.
- greenhouse gases: A natural or manmade gas that traps heat in the Earth's atmosphere and contributes to the greenhouse effect. The main greenhouse gases are water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone and industrial gases such as chlorofluorocarbons (CFCs). These gases in the Earth's atmosphere trap warmth from the Sun and make life possible. An overabundance of greenhouse gases leads to a rise in global temperatures – known as the greenhouse effect.
- climate: The weather conditions of an area averaged over a series of years, usually 30 or more.
- condition: An existing state or situation; a mode or state of being.
- primary industry: This umbrella term refers to industries that are making direct use of natural resources. Primary industries in New Zealand include agriculture, horticulture, aquaculture, forestry and mining.
- optimum: The best or maximum that can be achieved.
- climate change: The large-scale, long-term increase in the Earth’s average temperatures, with associated changes in weather patterns. There is significant scientific evidence that warming is due to increased quantities of greenhouse gases in the atmosphere, with most of the rise due to human activity.
- erosion: Wearing away of the land by mechanical action, such as by wind, water and glaciers, and by material carried in them. It can also be the gradual wearing away of a surface due to friction, particle collisions or chemical attack. Part of the process of erosion transports material away.
- sediments: Material that settles to the bottom of a liquid. In geology, it describes the solid fragments of inorganic or organic material that come from the weathering of rock and are carried and deposited by wind, water or ice.
- soil structure: The way that soil particles are arranged together.
- nitrous oxide: N2O. A naturally occurring atmospheric gas. It is used as a mild anaesthetic and as a fuel. It is also a greenhouse gas.
- infrastructure: The basic facilities and services needed to support a community, such as transport, water, power, wastewater and stormwater management, and public institutions including schools, post offices and prisons.
- climate change: The large-scale, long-term increase in the Earth’s average temperatures, with associated changes in weather patterns. There is significant scientific evidence that warming is due to increased quantities of greenhouse gases in the atmosphere, with most of the rise due to human activity.
- species: (Abbreviation sp. or spp.) A division used in the Linnean system of classification or taxonomy. A group of living organisms that can interbreed to produce viable offspring.
- temperature: A measure of the degree of hotness or coldness of an object or substance. Temperature is measured with a thermometer calibrated in one or more temperature scales. Kelvin scale temperature is a measure of the average energy of the molecules of a body.
- forage: Plant material eaten by grazing livestock. It includes pasture plants like grasses, legumes and herbs as well as plants that are cut and carried to the animals, such as silage or hay.
- biosecurity: The process of preventing, detecting and controlling unwanted pests and diseases.
- diseases: 1. An abnormal condition of an organism that impairs bodily functions. 2. In plants, an abnormal condition that interferes with vital physiological processes.
- greenhouse gases: A natural or manmade gas that traps heat in the Earth's atmosphere and contributes to the greenhouse effect. The main greenhouse gases are water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone and industrial gases such as chlorofluorocarbons (CFCs). These gases in the Earth's atmosphere trap warmth from the Sun and make life possible. An overabundance of greenhouse gases leads to a rise in global temperatures – known as the greenhouse effect.
- gases: The state of matter distinguished from the solid and liquid states. Gases have the ability to diffuse readily and to become distributed uniformly throughout any container.
- methane: CH4, a gas that contributes to the greenhouse effect.
- ruminants: Herbivorous, hoofed mammals, for example, sheep, cattle, deer and camels, that have a complex 3 or 4-chambered stomach. They use a fermentation process in their rumen to break down plant material.
- transform: To be given a completely different form or appearance.
- nitrogen: A non-metal – symbol N, atomic number 7. Nitrogen is essential for life. It is a component of many molecules that make up cells, including DNA and proteins.
- fertiliser: Compounds that are given to plants to promote growth.
- precipitation: 1. The formation of an insoluble solid (precipitate) from a given solution by altering either its temperature, concentration or chemical composition. 2. In meteorology, this term describes the formation of rain, hail, snow or ice in the atmosphere.
- data: The unprocessed information we analyse to gain knowledge.
- oxide: A chemical compound made up of oxygen combined with at least one other element. Most of the Earth’s crust consists of oxides.
