According to the Ministry for Environment of New Zealand, gross greenhouse gas (GHG) emissions decreased by 1% in 2018, to reach 79 MtCO2eq. The drop in GHG emissions was mainly due to a decline in emissions from the energy sector (-3%), driven by outages at the Pohokura natural gas field and higher levels of hydro generation (60% in 2018). In 2018, CO2 accounted for 44% of total emissions, followed by methane (43%, mainly biological methane from livestock), nitrous oxide and fluorinated gases (2%). The Land Use, Land-Use Change and Forestry (LULUCF) sector offset 30% of New Zeeland’s gross emissions, with net emissions reaching 55.5 MtCO2eq.
Since 1990, New Zealand’s gross GHG emissions increased by almost a quarter (+24%), due a higher fuel consumption in road transport that contributed to a 38% growth in CO2 emissions, increased fertiliser use (NOx emissions rose by 54%), emissions from dairy cattle (+6% for CH4 emissions) and increased use of hydrofluorocarbon-based refrigerants (fluorinated gases). When taking the LULUCF sector into account, the volume of timber harvested from New Zealand’s plantation forest estate rose significantly between 1990 and 2018, raising the country's net GHG emissions bt 57% over the 1990-2018 period.
In November 2019, New Zealand adopted a law aiming to cut CO2 emissions to net-zero by 2050, making the new 2050 greenhouse gas (GHG) reduction target legally binding. The government had approved a law to make New Zealand carbon neutral by 2050, except for GHG emissions of the agricultural sector. According to the bill, methane emissions from animals will have a different treatment, but will still have to reduce by 10% by 2030 and by up to 47% by 2050. The bill also established a Climate Change Commission in charge of elaborating a roadmap and plan to be updated every five years. In its Nationally Determined Contribution (NDC) submitted in 2016, New Zealand committed to reduce its GHG emissions to 30% by 2030, compared to its 2005 levels.