Greenhouse Gas Emissions

Greenhouse gases such as carbon dioxide, methane, nitrous oxide and water vapour act to absorb the sun’s heat and warm the atmosphere. The heat-absorbing gases act like the panes of glass in a greenhouse, protecting the Earth from extreme changes in daily temperatures.

Extra emissions of these gases due to the use of fossil fuels and other sources have increased the rate of global warming, which has affected the climate and created a significant global issue. Since 1950, temperatures have increased by 0.9°C across most areas of Australia, with more heat waves, fewer frosts and less rain in southern and eastern Australia.

Agriculture contributes 16% of Australia’s greenhouse gas emissions. Ten per cent of agriculture’s greenhouse gas emissions are attributed to dairy farming. This corresponds to 1.6% of national greenhouse gas emissions.

The two largest sources of greenhouse gas emissions from dairy farms are methane from the rumen, and nitrous oxide from urine and nitrogenous fertiliser.

Methane absorbs the sun’s heat 21 times more than carbon dioxide and has a global warming potential of 21. Nitrous oxide is far more powerful again and has a global warming potential of 310.

The losses of methane and nitrous oxide represent inefficiencies and losses of energy in our current dairy systems.

Greenhouse emissions are increased when cows are fed poor-quality diets or nitrogen fertiliser is managed poorly. By applying current best management practices for grazing management, balanced dairy cow nutrition and nitrogen fertiliser management we can reduce methane and nitrous oxide emissions and improve the efficiency of dairy production.

Planting trees for shade, shelter and biodiversity offers opportunities for the sequestration of greenhouse gas emissions and the potential to generate credits to offset future emission reduction liabilities.

Better management of greenhouse gas emissions should be seen as a win-win opportunity and not a threat to the dairy industry.

What you gain and what it costs

At work on the farm

Andy and Diana Thomas, Krowera, Victoria

Like many farmers, Andy and Diana Thomas from Krowera, Gippsland, are experiencing the effects of increased climate variability and climate change (longer dry spells, higher temperatures, changes in the growing season), and have decided to prepare their business for what lies ahead.
To help identify possible changes, they took part in the Western Port Greenhouse Action and Resource Efficiency Project that looks at ways of reducing water use, greenhouse gas emissions and waste.

Energy

An audit of the Thomas’ dairy shed found that the cooling water was retaining too much heat from the previous milking. This meant that more energy was required to bring the milk temperature down to the desired level. The auditor suggested re-connecting the cooling tower fan and using night-sky cooling, a $5000 investment that could result in an annual saving of more than $1000.

Pasture and vegetation

Cows fed on high-quality pasture produce less enteric methane. With the likelihood of drier conditions and shorter growing seasons, Andy and Diana are investigating the use of new pasture species that improve both pasture quality and drought tolerance.

Andy and Diana’s grazing management is tied to their efforts to provide more shade and shelter through increased tree plantings. So far they have increased their number of paddocks from 20 to 40. With many more paddocks available to them, Andy and Diana have greater control over grazing patterns, and can improve the quality of the pasture they produce and reduce their greenhouse
gas emissions.

Do any of these look familiar?

What you need to know (Victoria only)

1. A t this stage there are no laws governing greenhouse emissions from farming operations, but it is highly likely greenhouse gas emissions will attract a carbon cost in the future.
2. While agriculture is currently exempt from the Australian emissions trading scheme the intention is to include it once the practical issues have been resolved.
3. Consumers and global markets are increasingly seeking evidence of ‘green’ production systems and ‘greenhouse friendly’ produce.

Additional information

These resources can help you develop your Action Plan (Organisations, their contact details and website information were correct at the time of publication. Information may change without notice).