Where is NZ’s carbon capital? – Expert Reaction

Stats NZ has released figures showing each region’s greenhouse gas emissions over ten years.

Overall, Waikato emitted the most greenhouse gases in 2018. From 2007-2018, Canterbury had the most significant increase (11 per cent) in its emissions.

The SMC asked experts to comment on the figures. 

Distinguished Professor Robert McLachlan, School of Fundamental Sciences, Massey University, comments:

“For the first time, Statistics New Zealand has produced a breakdown of greenhouse gas emissions by region as well as by who is producing them (households, primary industries, goods-producing industries, and primary industries). They confirm that emissions from the burning of fossil fuels remains stubbornly high, having remained near their peak since the mid-2000s. Reductions from the electricity sector have been offset by uncontrolled increases in cars and trucks.

“Falls in some areas (mostly fossil-fueled power stations in Auckland and Waikato) have been offset by increases in others: Canterbury has overtaken Waikato in 2018 as the region with the highest agricultural emissions.

“But as a ‘team of five million’ (or a world of eight billion), the key point is not the location of the polluter but the development of an overall plan to stop burning fossil fuels. The regional councils that have declared climate emergencies (Auckland, Wellington, Canterbury, Bay of Plenty, Hawkes Bay, and Nelson, comprising two-thirds of New Zealand’s population) will be paying close attention.

“Key developments to watch out for include local plans, like Auckland’s inspiring target set this week to halve emissions in 10 years, and national emission reduction plans, especially for transport and industry, that are presently under development by the government and the Climate Change Commission.”

No conflict of interest declared.

Dr Sara Mikaloff-Fletcher, Atmosphere-Ocean Scientist, NIWA, comments:

“The Stats NZ regional greenhouse gas data released today fill a crucial gap in Aotearoa New Zealand’s emissions data and may play a key role in supporting our transition to a low carbon economy. The Ministry for the Environment (MfE) currently reports Aotearoa New Zealand’s national greenhouse gas emissions each year. This national scale reporting is a fundamentally important work, which is required to assess whether we have met emissions targets set out in international climate treaties such as the Paris Climate Agreement.

“Yet, much of the planning and decision making needed to reduce emissions in practice occurs at regional scale. The new Statistics NZ data provide the first regional breakdown of our emissions, compiled using uniform methodology across every region in the country. Their aspiration to update this information annually will allow regional councils and community groups to not only plan effective action but track their progress.

“This represents an important first step towards providing high quality regional information about our greenhouse gas emissions, but an essential piece is still missing from the puzzle. These statistics do not yet include the carbon emitted or absorbed due to the way we care for our land, e.g. cutting or planting trees, soil management on farms, urban green spaces, invasive pest eradication, etc. Yet, land management, particularly re-forestation, is a key strategy to slow climate change for many regions.

“Atmospheric observations may hold the key to providing better regional information in the future. As air passes over the land, it gains or loses carbon due to exchange with the underlying biosphere. Therefore, when atmospheric gas measurements from a network of sites around New Zealand are combined with weather model simulations that tell us the pathway air took before arriving at a site, we can determine the total amount of carbon that has been absorbed or emitted. These methods will not replace the approach used by Stats NZ or MfE, but they can provide independent verification and shed light on terrestrial processes that are difficult to estimate directly, particularly carbon exchange in the land biosphere.

“CarbonWatch NZ is a collaborative research programme that uses these atmospheric data to infer regional and national emissions or uptake. We are in the process of deploying new observing sites that will target all of the three regions that Stats NZ have identified as the largest emitters: Waikato, Auckland, and Canterbury, as well as targeting forest carbon uptake in Fiordland, Raukumara Forest, and on the banks of Lake Taupo. This project will enable us to provide better regional data on the impact of land management decisions in the future to support New Zealand’s Carbon Zero goals.”

No conflict of interest.

Professor Emeritus Ralph Sims, Sustainable Energy and Climate Mitigation, Massey University, comments:

“For the first time, Stats NZ has presented the greenhouse gas emissions released directly in each of the 14 regions of New Zealand. The trends from 2007 till 2018 (latest data available) portray an interesting story.

“However, care is needed when interpreting the data since the methodology used do not relate to the direct consumption of products and services in each region. Instead the data is measured from which region the emissions actually arise. Thus emissions from say a gas-fired power station in Taranaki are assessed for that region, and not for the regions where that electricity is consumed.

“To comprehend the data, it is also important to understand some key trends that have occurred during the 11 year period. For example:

  • Renewable electricity generation has increased its share of the total annual generation.
  • Dairy farming has increased, particularly in the lower South Island.
  • Total population has increased, particularly in Auckland and the Bay of Plenty.
  • Private cars have increased in number and size (e.g., utes and SUVs are now far more popular than they were in 2007).
  • Tourism has also increased (but noting that all the data is pre-COVID-19).

“The emission data as presented for each region is mostly shown for all greenhouse gases added together as ‘carbon dioxide equivalents’. However, when carbon dioxide (mainly from energy-related emissions) is separated from methane and nitrous oxide (mainly from agricultural emissions) this can result in different conclusions being drawn between urban and rural regions.

“For example, Waikato had the highest share of total emissions in 2018 (17.5%) due to both having the highest number of cattle (around 2 million) but also the Huntley coal-fired power station and some geothermal power plants (that also emit carbon dioxide) are located there. Over the 11-year period total emissions declined around 2%. Conversely the Bay of Plenty only had 4.3% of total emissions but had the highest increase over the period of 11.9% mainly due to the major increase in population there.

“Canterbury was the second highest emitting region and had increased its emissions by 11%. Together with Southland (7.3% increase) and Otago (6.5% increase) this was mainly due to increased cattle numbers and probably the associated milk processing plants consuming coal for process heat.

“Auckland was the third highest emitter, mainly due to its increase in population and related transport, although overall emissions declined 7.8% as the increase in household emissions was offset by a reduction in goods-producing industries.

“Southland had the highest emission intensities per capita and per GDP in 2018, which is not surprising given its relatively low population versus the high emitting local agricultural industry and the aluminium processing at Tiwai Point (even though the smelter consumes low-carbon hydro electricity). This reinforces the point that directly comparing regions must be undertaken with care and take regard of the specific circumstances from where the emissions arise.

“Regions with the greatest reductions over the 11 years were Taranaki (-11.3%), Gisborne (-10.9%) and Northland (-10.8%) followed by Auckland. However, given these reductions did not result from any specific greenhouse gas mitigating policies, these regions cannot rest on their laurels.

“Across all regions a 1.2% reduction in emissions was calculated. However, our total greenhouse gas emissions per capita remain one of the highest in the world at 16.2 tonnes per person in 2018. Perhaps the overall message from the analysis is that a major effort to reduce emissions in the next two to three decades is essential in every region in order to rapidly drive down our total emissions and meet our international commitment. If we are to stay below the 2oC target of the Paris Climate Agreement (never mind 1.5oC), the commitments of all countries including New Zealand have to become far more ambitious.

“This will require strong leadership, robust policies, tough regulations and personal commitments by our team of five million to all play their part by lowering personal carbon footprints.

“Without these measures, the drought followed by the floods recently experienced by Northland will pale into insignificance as the present global temperature rise (already at around 1.1oC) heads towards the projected 3 to 4oC within a few decades if no urgent action is taken.”

No conflict of interest.

Dr Laura Revell, Senior Lecturer, School of Physical and Chemical Sciences, University of Canterbury, comments:

“Greenhouse gas emissions are reported relative to their 100-year global warming potential (GWP). The GWP metric quantifies how effective a particular gas is at heating the atmosphere relative to carbon dioxide. Methane, nitrous oxide and fluorinated gases have much higher 100-year GWPs than carbon dioxide, therefore although they are emitted in relatively small quantities their contribution to New Zealand’s overall emissions profile is significant. This is especially true of methane and nitrous oxide, which are associated with agriculture.

“Agriculture accounted for more than half of the 2018 total regional industry emissions and was dominated by Canterbury and Waikato followed by Manawatū-Whanganui, Otago and Southland. Waikato was the highest emitting region overall, although total emissions decreased in the region by 272 kilotonnes (CO2-eq) or 2 per cent between 2007 and 2018. Canterbury recorded the largest change in emissions over the same period of 1,175 kilotonnes (CO2-eq), an 11 per cent increase, which was driven by dairying. Unsurprisingly, given the links to agriculture, Canterbury and Waikato emitted larger amounts of nitrous oxide and methane than any other region. Along with contributing to climate change, nitrous oxide is damaging to the protective ozone layer.

“Interestingly, the two regions with the highest regional GDPs (Auckland and Wellington) also had the lowest emissions intensity per $1m of GDP, indicating that economic activity is not necessarily linked to CO2-eq greenhouse gas emissions. The Auckland region saw a large reduction in industrial emissions of 16 per cent, however household emissions rose by 18 per cent. The increase in household emissions is in line with population increase in the region and the associated car emissions and fuel consumption. This indicates that as our cities grow, widespread use of electric vehicles, public transport, walking or cycling along with careful urban planning could make an important difference to New Zealand’s carbon footprint.”

No conflict of interest.