Stats NZ's latest regional greenhouse gas stocktake has again highlighted New Zealand's energy vulnerability to dry weather, finding that total emissions rose in 2019 on the back of coal use.
Over that year – when total regional emissions by increased 2.1 per cent – Waikato, home of the Huntly Power Station, saw the largest annual jump, up 1085 kilotonnes of carbon dioxide equivalent (CO2-e), or 7.5 per cent.
In 2019, hydro-generation dipped due to low rainfall in the North Island, and as a result electricity generation from coal and gas increased.
That's been similarly seen this year, with the country burning through more than a million tonnes of coal in 2021's first six months – more than any full year in nearly a decade – because of low hydro-lake levels and gas shortages.
All the while, nations have been coming under mounting pressure to phase out coal use, ahead of next month's UN climate summit in Glasgow.
Auckland's increase was meanwhile driven by manufacturing, which was up 3 per cent in 2019 compared with 2018, and accounted for 41 percent of its total industry emissions.
In 2019, the largest falls in emissions were in Canterbury, down 179 kilotonnes (1.5 per cent), Gisborne, down 48 kilotonnes (3.5 per cent), and Tasman, down 35 kilotonnes (3.9 per cent).
Canterbury emissions were down largely due to declining livestock numbers - dairy cattle and pigs in particular.
In 2019, the top three emitting regions – Auckland, Waikato, and Canterbury – accounted for 47 percent of total regional emissions.
Stats NZ noted that the high contributions of those regions to total emissions reflected both population size and the presence of emissions-intensive industries.
Auckland, which contributed the most of any region to national economic activity (GDP), was the third highest emitter of greenhouse gases in 2019.
While Wellington and Canterbury had similar economic output contributions, the two regions turned out different emissions contributions, with Wellington contributing 4.3 per cent and Canterbury 14 percent of all greenhouse gas emissions.
"This illustrates how the structure of the regional economy influences regional emissions intensity," Stats NZ's environmental-economic accounts manager Stephen Oakley said.
"A regional economy with more service industries generally produces fewer emissions per unit of GDP compared with a regional economy with a higher proportion of primary and goods-producing industries.
"Wellington has a higher proportion of service industries compared with Canterbury and is therefore less emissions intensive."
Today's report came after the Ministry for the Environment's greenhouse gas inventory showed our emissions leapt by 26 per cent - or some 17.2 million metric tonnes of carbon dioxide (Mt CO2-e) - between 1990 and 2019.
But most of that increase came from methane belched by dairy cattle and CO2 from road transport.
The inventory showed that, despite increased efforts to decarbonise, both gross and net emissions rose by around 2 per cent in 2019.
In that case, the bump was mainly down to emissions rises in manufacturing industries and construction, along with public electricity and heat production.
Overall, New Zealand's emissions in 2019 amounted to 82.3 Mt CO2-e, of which about 46 per cent came from CO2, 42 per cent from methane, and 10 per cent from nitrous oxide.
About 33 per cent of that was offset by land use and forestry - a sector whose net CO2 removals had climbed by about 14 per cent since 1990.
Earlier this year, the Climate Change Commission warned that New Zealand was on track to fall short of its 2050 target for net zero emissions of long-lived greenhouse gases by millions of tonnes of CO2-e.
It's recommended budgets – involving slashing livestock numbers, winding down petrol car imports and planting more forestry - that could drive down carbon emissions by 63 per cent, and biogenic methane by 17 per cent, all within the next 15 years.
That would put us on track to meet our target of net zero emissions of long-lived greenhouse gases by 2050 – and also bring down biogenic methane emissions by between 24 and 47 per cent.
It's unclear how much of the commission's recommendations will be fed into the Government's own Emissions Reductions Plan, which now won't be released until May because of Covid-19 disruption.