PHOTO: Ruben de Rijcke - Own work, CC BY-SA 3.0,

Emissions dropped over Delta lockdown – Expert Reaction

Greenhouse gas emissions from certain sectors fell 11 per cent over the September 2021 quarter according to new Stats NZ figures, with Covid-19 restrictions taking place during the second half of the period.

While the lockdown contributed to the drop, Stats NZ also said it was largely due to a reduction in coal use for electricity generation. The figures report seasonally adjusted greenhouse gas emissions from industries and households.

The SMC asked experts to comment on the data.

Dr Hinrich Schaefer, Atmospheric Scientist, NIWA, comments:

“The prominent drop in greenhouse gas emissions is clearly linked to protection measures against Covid-19, since over the last six years a similar decrease occurred only during the 2020 lockdown period.

“Aotearoa-New Zealand will have to continually reduce emissions at similar rates over the next decades in response to the climate crisis. Therefore, the breakdown of the current drop holds lessons how to cut greenhouse gases most efficiently, even though such lessons require further thought and research.

“After the 2020 lockdown, emissions dropped but rebounded right away. Identifying which type of emissions were avoided through the lockdowns in the long run can show us effective and sustainable mitigation targets.

“Compared to 2020, this year’s emission decrease went with a lower loss of GDP, probably because the lockdown was largely restricted to the Auckland area. The primary sector and mining maintained their emissions, which are dominated by the gases methane and nitrous oxide. More fundamental and structural change will be needed for long-term greenhouse gas reductions from these industries.

“The biggest emissions drop is in the infrastructure of industrial activities (energy and water supplies, waste) and is three times as large as the drop in emissions directly attributed to manufacturing. This points to big gains in long-term emissions reductions if the energy infrastructure of our industry is improved. Construction and transport are the other sectors with large reductions in emission. This shows the potential in sustainable reductions by restructuring transport and the need to move to low-emissions materials and processes in construction.”

No conflict of interest.

Distinguished Professor Robert McLachlan, School of Mathematical and Computational Sciences, Massey University, comments:

“It’s welcome to see a fall in emissions from electricity generation. As well as the shift from coal to hydro, new wind farms began operation. 2021 saw a record level of new wind and solar projects announced so we can expect electricity emissions to continue to fall and for fossil fuel power stations to be decommissioned over the next few years.

“It is interesting to see industrial emissions falling five per cent while their GDP increased 3.5 per cent. Is this a Covid-related shift, or the start of decarbonisation?

“The bigger picture is unclear due to Covid. Annual emissions were similar to the previous year at 81 million tonnes CO2e, down on pre-Covid levels of 85 million tonnes. This is mostly due to international aviation, which Stats NZ includes where the Ministry for Environment generally does not. As no measures are in place yet to address international aviation emissions, this can be expected to bounce back post-Covid.

“Apart from lockdowns, there appear to be underlying six per cent annual increases in household transport emissions. They likely have not even peaked yet, let alone begun a decline. The ground-breaking Clean Vehicles Plan is a first step to addressing these but a lot more needs to happen as well. This is an area where the Emissions Reduction Plan (due in May) and the promised ‘climate budget’ can make a difference.”

No conflict of interest.

Dr Olaf Morgenstern, Principal Scientist – Atmosphere and Climate, NIWA, comments:

“My comment would be that drops of this order, and repeated in the years to come, are required if we are to reach carbon neutrality by 2050. Covid-19 is an unusual, and unusually disruptive reason for these drops. We won’t want to resort to lockdowns to reach carbon neutrality. Also the reduction in coal burning at Huntley, the fossil-fuel power plant in the Waikato, may be due to relatively good hydropower generation in the South Island.

“So I would not read too much into these figures. They don’t reflect sustained changes in our economy that would indicate that we’re on a path to carbon neutrality.”

No conflict of interest.

James Renwick, Professor of Physical Geography, Victoria University of Wellington, comments:

“The latest numbers on national carbon dioxide emissions show that reducing coal burning can have a significant effect on total emissions. The other factor in recent reductions has been Covid-related lockdowns in the second half of 2021.

“What we need is to find ways to reduce emissions without lockdowns and damage to business and the economy, via increased use of electric vehicles, much improved public transport, and installation of new wind and solar generation to phase out coal across the board. Emissions decreased significantly in 2020 and into 2021 and there was a lot of talk of a ‘green recovery’ and of keeping emissions tracking downwards. That doesn’t seem to have happened consistently, which is worrying.

“Unless we really get CO2 emissions on a downward path, here and internationally, we are on a path to an unmanageable climate.”

Conflict of interest statement: James Renwick is a Climate Change Commissioner. He receives MBIE funding for climate research.