Greenhouse Gas Emissions

The earth is heating up due to rapidly increasing concentrations of greenhouse gases in the atmosphere. Significant changes to the climate are occurring as a result, which affect our natural environment, primary sector, infrastructure and built environment, as well as human health.

Many gases created by human activities act as greenhouse gases, but the three most important from a New Zealand perspective are:

Carbon dioxide (CO2): Carbon dioxide enters the atmosphere when fossil fuels (oil, natural gas and coal), solid waste, trees and wood products burn, and during other chemical reactions such as manufacturing cement. Carbon dioxide is removed from the atmosphere by growing plants, which absorb and store it in their tissue. It gets released again when plants decay as part of the biological carbon cycle. Carbon dioxide from fossil fuels makes up 44% of New Zealand’s gross annual greenhouse gas emissions. Carbon dioxide is also emitted during application of urea and lime.

Methane (CH4): Methane is emitted during the extraction and transportation of coal, natural gas and oil. Methane emissions also come from livestock and agricultural practices such as growing rice, and by the decay of organic waste in landfills. It makes up 43% of New Zealand’s gross emissions, mainly from cattle and sheep.

Nitrous oxide (N2O): Nitrous oxide is emitted during agricultural and industrial activities, and when fossil fuels and solid waste burn. It makes up 12% of New Zealand’s gross emissions. 

• Producing more per cow means you have lower emissions due to less metabolic maintenance overheads. In an integrated context, fewer cows allows more space for activities such as biodiversity; lower staff requirements and more attention to care for each cow enables better animal health and welfare.
• Reducing additional Nitrogen (N) onto pasture through pasture management actions  such as planting more clover which naturally captures N, could help reduce fertiliser costs and the farm inputs budget.
• Plantain is a pasture plant which helps minimise N loss by several clever mechanisms such as diluting the concentration of N in cattle urine.
• Breeding from only the best performing stock from sexed semen means less young to slaughter and better performing, smaller cows which produce lower emissions. Smaller cows have lower body maintenance requirements and cause less damage to soils which can reduce erosion and water quality issues.

Climate change basics reproduced above from AgMatters