Revealed: NZ households' impact on climate change

The average household's emissions fell 11 percent between 2006 and 2012, mostly because the production of some high-emissions goods is creating fewer greenhouse gases. Photo / File

New data has revealed a notable drop in the average Kiwi household's greenhouse gas emissions, as production of meat, dairy and electricity becomes more climate-friendly.

But the researchers behind the report say further cuts to agricultural emissions will be needed to slash New Zealand's contribution to global warming.

The paper, published by Wellington-based Motu Economic and Public Policy Research, found the average household's emissions fell 11 percent between 2006 and 2012, mostly because the production of some high-emissions goods is creating fewer greenhouse gases.

In particular, improvements in carbon intensity were made in milk, cheese and eggs, meat and poultry, air travel, and electricity.

"For example, emissions intensity of meat fell nearly 10 per cent because of how farmers now produce their beef and lamb," said Dr Suzi Kerr, a senior fellow at Motu.

"So it's not that people are eating less red meat, because they're not.

"Instead, our farmers have done a lot through pastoral grazing systems and efficiency measures to reduce greenhouse gas emissions."

But despite the improvements, it was clear that further cuts in our agricultural emissions by both producers and consumers were needed, she said.

"Many policies, possibly including bringing agriculture into our emissions trading scheme could facilitate this."

Food, particularly red meat and dairy, household utilities, particularly electricity and gas, and transport account for 89 per cent of emissions for the average household.

"It's been great to see the emissions intensity of electricity fall by more than 25 per cent over the period we studied."

Much of this was due to the increased share of renewable energy in New Zealand's generation mix.

"Kiwis also used less electricity, probably because of higher prices and gradual energy efficiency improvements like insulation, so overall average household emissions from electricity consumption fell by 30 per cent."

Unfortunately, emissions from petrol increased about 10 per cent as regular petrol became "dirtier".

Because households also consumed more fuel, average household transport emissions rose about 28 per cent.

In contrast, air travel became more greenhouse gas efficient, due to airplane improvements and better fuel efficiency.

"Household emissions from air travel fell even though wealthier households are doing more air travel than they were."

How much a household spends, and who lives in it explains nearly 70 per cent of the variation in emissions across households.

The relative importance of the different categories changed with a household's income.

Food emissions made up roughly 40 per cent of emissions, no matter the income, while utilities contributed about 30 per cent of emissions for poorer households but just over 20 percent for the wealthiest households.

The importance of transport emissions increased as households become wealthier, with the share rising from about 20 per cent to about 25 per cent.

"However, it's not just the level of expenditure that is important in determining emissions; the choices households make about what goods to consume also have large impacts," Kerr said.

If the top and bottom 10 per cent of emitters were compared at each income level, emissions from meat and dairy were 251 per cent higher in the most emitting households than the lowest emitting households, while emissions from petrol and diesel were 377 per cent higher.

The bigger picture also showed New Zealand was making a disproportionate impact on climate change.

According to a Ministry for the Environment report this year, New Zealand's gross emissions have now risen by 23 per cent, and net emissions by 54 per cent, since 1990.

New Zealand's gross emissions per person were now fifth highest out of the 41 countries which set reduction targets under the 1997 Kyoto Protocol, and our net emissions were the 14th highest.

As part of the Paris Agreement, New Zealand has pledged to slash its greenhouse gas emissions by 30 per cent from 2005 levels and 11 per cent from 1990 levels by 2030.