How our land use contributes to climate change
Our activities contribute to climate change. Changing temperatures may affect the way we use our land in the future.
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The way we use our land has the biggest impact on our greenhouse gas emissions. More than half of our gross greenhouse gas emissions (methane, nitrous dioxide and carbon dioxide) are from agriculture.
For example, livestock rearing is responsible for 86 per cent of our total methane emissions and 92 per cent of our total nitrous dioxide emissions.
In recent years, the shift from beef to dairy farms has contributed to increased greenhouse gas emissions. This is because dairy cows emit more methane and excrete more nitrogen per animal than sheep and other cattle.
The manufacture and transport of fertiliser produces nitrous dioxide emissions. Emissions from fertiliser made the second largest contribution to greenhouse gas emissions from our dairy farms after those from animals. Emissions from fertiliser make up a total of 15 per cent of our farms’ carbon footprint.
Extreme weather events like floods, droughts and heatwaves are projected to increase across the country as temperatures rise.
These extreme weather events will change how we use our land and potentially will make some land unusable in the future.
Droughts, for example, can have a significant effect on the land and the people making a living from it. Between 2007 and 2017 droughts cost New Zealanders an estimated $720 million in insured damages and economic losses.
Sea level rise would make some land areas less viable for use due to flooding and coastal erosion. Since we began keeping records 100 years ago, our relative sea level rose by an average of 1.81 milliliters per year. It is projected that our sea levels will rise by 0.5 metres between 2060 and 2110.
Climate change will also affect our primary industries. It will challenge the sustainability of our production systems. It will also provide new opportunities.
Warming temperatures, for example, would make the growing season longer and may expand the range of crops that could be grown.
On the other hand increased extreme weather events (like droughts) will add new pressures, like crops drying up or heat stress for animals.
In many parts of Aotearoa New Zealand local governments have created plans to reduce greenhouse gas emissions and manage the risks from sea-level rise and flooding.
Most plans aim to reduce greenhouse gas emissions to zero by 2050 which follows the Paris Agreement and Zero Carbon Act timeline. Some have a longer timeframe (eg, the 100-year plan to address coastal erosion in Hawke’s Bay).
These plans may change how we use our land or affect economic markets. In turn this could affect how our land is used in the future.
Ultimately the global population needs to lower its greenhouse gas emissions to combat the worst effects of climate change. This will require us to change the way we use our land.
Options for reducing greenhouse gas emissions from use of our land include:
- lowering the density of dairy cows, sheep and other livestock
- improving animal performance
- using less fertiliser
- breeding sheep (which produce fewer emissions than cows).
Find out more in Our land 2021 report
Find out more about climate change in Our atmosphere and climate 2020 report