Canterbury experienced the largest increase in greenhouse gas emissions among New Zealand regions in 2025, despite a nationwide overall decline, according to recent data from Stats NZ. The region’s emissions rose by approximately 314,000 tonnes of carbon dioxide-equivalent, representing a 2.5% increase, while national emissions fell by 2.5% during the same period.
The rise in emissions in Canterbury was primarily driven by the agricultural sector, which saw an increase of about 331,000 tonnes, offsetting reductions in household emissions that fell by 18,000 tonnes. Methane and nitrous oxide accounted for the bulk of these increases, with methane emissions rising by around 221,000 tonnes and nitrous oxide by approximately 68,000 tonnes. Both gases are closely linked to pastoral farming activities—methane from ruminant animals such as cows and sheep as they digest feed, and nitrous oxide largely from animal urine and nitrogen-based fertilisers.
Tim Clough, a professor at Lincoln University, noted that while dairy cow numbers in Canterbury have remained relatively stable, productivity per animal and per hectare has increased. This higher productivity tends to require greater feed intake, which can lead to enhanced methane and nitrous oxide emissions. However, Clough also pointed out that other factors could be contributing to the rise, such as sheep populations, fertiliser application, weather conditions, and Canterbury’s extensive irrigation infrastructure. He mentioned that nitrogen fertiliser use has slightly declined, which might place more emphasis on emissions tied directly to ruminant animals.
The regional divergence in emissions trends is particularly notable. While Canterbury’s methane emissions rose sharply, southern regions like Otago and Southland reported significant decreases—methane emissions fell by 213,000 tonnes and 214,000 tonnes respectively, with nitrous oxide emissions also declining in these areas.
Changes in regional regulatory frameworks may also be influencing agricultural emission trends. Since the expiry of temporary national rules in early 2025 that required resource consent for converting land to dairy farming, Environment Canterbury (ECan) has approved conversions and expansions that could accommodate nearly 35,000 additional dairy cows. This potential increase represents almost 4% of Canterbury’s existing dairy herd, though not all consented capacity is expected to be fully utilised.
The expansion of dairy farming presents a challenge to Canterbury’s environmental objectives. ECan declared a climate emergency in 2019 and has since declared a nitrate emergency in response to rising concerns about groundwater contamination, underscoring the complexity of balancing agricultural growth with environmental stewardship in the region.