Global greenhouse gas emissions largely come from:
- burning fossil fuels – for example, burning coal for electricity production and using fossil-fuelled vehicles for transport
- cement production
- burning natural gas associated with oil extraction (flaring)
- land-use changes – for example, clearing tropical rainforests and other vegetation for human settlements and agriculture (IPCC, 2014).
Global net greenhouse gas emissions show a statistically significant increasing trend. In 2011, estimated global net greenhouse gas emissions were 33 percent higher than 1990 levels. From 2000 to 2010 emissions were the highest they ever have been (IPCC, 2014).
New Zealand’s overall contribution to global emissions is small, but our emissions per person are among the highest in the world
Between 1990 and 2011, New Zealand emitted an average of 0.1 percent of global net greenhouse gas emissions. While New Zealand’s overall contribution to global emissions is small, in 2012 our emissions per person were the fifth-highest of 41 developed countries with international commitments on climate change (Ministry for the Environment, 2016).
In 2014, the agriculture sector (for example, from nitrous oxide from fertiliser and methane from livestock) contributed 49 percent to New Zealand’s gross emissions. The energy sector, which includes road transport and electricity production, contributed 40 percent to gross emissions (Ministry for the Environment, 2016).
For more detail see Environmental indicators Te taiao Aotearoa: Global greenhouse gas emissions.
Global concentrations of atmospheric carbon dioxide are at levels unprecedented in human history
Carbon dioxide is the greenhouse gas that has the greatest impact on warming the planet over the long term because it persists in the atmosphere longer than other natural greenhouse gases. Global atmospheric concentrations of carbon dioxide are now at levels unprecedented in at least the past 800,000 years, which is the period for which records from ice cores are available (IPCC, 2013).
In New Zealand, the concentration of carbon dioxide in the atmosphere has increased 21 percent since observations began in 1972 at Baring Head near Wellington (see figure 2). The increase is statistically significant and is a major shift in the state of our atmosphere over a short time period. The Baring Head record is one of the world’s longest records of atmospheric carbon dioxide data, and shows similar results to observations in other locations around the world.
Note: Baring Head is near Wellington. Observations are made only when the wind is blowing from the south and away from any likely local sources of gas emissions. This gives a measure representative of the concentrations over the Southern Ocean. Data are unavailable for some periods.
This graph shows the carbon dioxide concentrations at Baring Head between 1972 and 2013. Visit the MfE data service for the full breakdown of the data.
For more detail see Environmental indicators Te taiao Aotearoa: Greenhouse gas concentrations.