Snow-where to go: Alpine grasshoppers will be amongst first victims of climate change in Aoteaora, but not the last 

Steve Trewick

The 2022 Winter Olympic Games presented us with the sickening spectacle of  artificial snowfields produced using fossil energy because the use of fossil energy has resulted in global temperature rise that now inhibits the natural accumulation of snow.   A crushing display of human indifference and misguided priorities.

The inconvenient lack of snow on skifields has critical biodiversity and ecosystem implications for Earth. A new study reveals that anthropogenic climate change will result in at least a quarter of our alpine species becoming extinct in the next 50 years. Species that are already endangered and others that are currently widespread could lose all their current habitat in Aotearoa New Zealand due to anthropogenic global warming. The future distribution of 12 grasshopper species were inferred by projecting current niche models onto the predicted New Zealand climate with 1oC or 3.7oC warming. The conclusion was that most of these alpine species that occur nowhere else on the planet, would lose at least 30% of suitable habitat.

The earth has already heated 0.66 oC in just 20 years, the  1oC threshold will soon be passed, and the IPCC has now emphasised that chronic failure to meet promises could soon push planetary heating beyond control. In the mountains of New Zealand we can expect the green rock-hopper will be extinct within a matter of years and our other widespread flightless grasshopper species will have reduced and fragmented habitat.

Populations of alpine animals are restricted to high-elevation ‘islands’ and most cannot jump or fly the gap to unconnected mountain habitat. This means that as the Earth warms, alpine species will find their habitat dwindling. In Aotearoa New Zealand most of our alpine plants and animals are found nowhere else in the world, and the list is growing with six new species of alpine wētā just described. [Listen here] When their habitat shrinks, we are set to lose a quarter of all our endemic alpine biodiversity, and that is just the start.

The treeline on a mountainside shows the climatic limit of conditions suitable for tree growth. At higher elevation, day-night and seasonal temperature extremes and aridity prevent trees establishing. That leaves the space open for other types of plants and alpine animals that can survive and reproduce in the short alpine growing season and stay alive through the winter. But with a warmer planet the treeline will move up, squeezing out our alpine ecosystems.

A clear and present danger

The IPCC has released its latest damning report in which they identify systematic and widespread failure to fulfil existing GHG emission reduction pledges. Solutions now require drastic action to curb GHG production AND work to recapture CO2 released into the atmosphere. COVID and recent wildfires and floods will be as nothing if continue with business as usual (BAU). The failure of governments around the world is our failure. Our indifference allows politicians to side-line the solutions in favour of perceived business interests, which we can translate as short-term gain. Politicians must be shown that business as usual  is not an option and all aspects of our existence need to be refocused on the climate problem.

Indifference now denies us the right to complain when the problems hits us; and they will hit us as individuals not future generations. The problem and the solution is not somewhere else, or someone else it is here and it is YOU.

Managing New Zealand’s greenhouse gas emissions from aviation

By Robert McLachlan and Paul Callister

New Zealand at COP26

On 10 November 2021 at COP26 in Glasgow, New Zealand along with twenty-two other countries joined the “International Aviation Climate Ambition Coalition”, committing to “Preparing up-to-date state action plans detailing ambitious and concrete national action to reduce aviation emissions and submitting these plans to ICAO well in advance of the 41st ICAO Assembly” . This Assembly of the UN’s International Civil Aviation Organization will take place in September 2022.

What would “ambitious and concrete action” to reduce aviation emissions look like for New Zealand?

Aviation is not only a large industry and a large emitter. It also underpins other sectors of the economy like tourism and trade, and it links globally dispersed families, even though an estimated 80% of the world’s population have never set foot on a plane. All of these aspects are particularly acute for New Zealand, whose geography and infrastructure influence even domestic travel. If a domestic Sustainable Aviation Fuel (SAF) industry were to develop, then agriculture, land use, and renewable energy use would be implicated as well. Psychologically, the rapid rise of cheap and comfortable air travel and its continued glamorisation in the media has built support for the status quo and made addressing its emissions more difficult politically.

If there is to be limited overshoot of 1.5 ºC, global net anthropogenic CO₂ emissions must decline by 45% from 2010 levels by 2030. As the chairs of the IPCC Special Report on 1.5 ºC write,

Without increased and urgent mitigation ambition in the coming years, leading to a sharp decline in greenhouse gas emissions by 2030, global warming will surpass 1.5 ºC in the following decades, leading to irreversible loss of the most fragile ecosystems, and crisis after crisis for the most vulnerable people and societies.

The Paris Agreement and the Zero Carbon Act

The 2016 Paris Agreement does not mention aviation specifically. Nevertheless, the agreement to limit warming to “to well below 2.0 ºC above preindustrial levels and pursuing efforts to limit the temperature increase to 1.5 ºC above preindustrial levels” and to reach net zero emissions globally in the second half of this century, does include all sectors, including international aviation and shipping, as does the agreement for developed countries to undertake “economy-wide” emission reductions.

The Zero Carbon Act adopts the 1.5 ºC target, interpreted as reaching net zero emissions of long-lived gases (mostly CO₂) by and beyond 2050, along with substantial cuts in short-lived gases (mostly methane). However, international aviation is not yet included either in the targets or the carbon budgets.

The urgent need to phase out the burning of fossil fuels, New Zealand legislation, the Government’s climate goals, international agreements, and emerging international action all point towards reducing aviation emissions.

In a new report, we survey a wide range of ‘Net Zero 2050’ scenarios for aviation and how they relate to New Zealand. A summary follows below.

Key aspects of New Zealand aviation emissions

  • CO₂ 4.9 million tonnes in 2019
  • Per-capita 6th highest globally at 1 tonne CO₂
    (cf. US 0.56t, EU 0.65t)
  • 12% of CO₂ emissions, cf 2.8% globally
  • Proven ability to grow emissions rapidly:
    International +40%, domestic +20% in 2015–2019
  • International passengers fell 97.6% in the 12 months to March 2021
  • Domestic aviation CO₂ included in NZ ETS and the falling cap on emissions
  • Founding member of the International Aviation Climate Ambition Coalition, committed to presenting an “ambitious and concrete national action plan” in 2022 to reduce aviation emissions

New Zealand’s aviation emissions

The factors behind aviation’s rapid growth are many, but two key ones are price and quality. Since Air New Zealand launched their Auckland–London flight in August 1982, prices have fallen 70% in real terms, while incomes have risen. Prices relative to income have fallen by a factor of 6. Long-haul flights have become steadily more reliable and comfortable over the decades.

More passengers means more flights. The Tourism Satellite Account lists more than 100 new and expanded routes during the 2015–2019 period of rapid growth, some of them extremely long, such as Auckland to Buenos Aires, Chengdu, Chicago, Doha, Dubai, and Ho Chi Minh City.

Our population has become more globally linked. In 1996, 17.5% of the New Zealand population were born overseas. In 2001, 19.5%; in 2006, 22.9%; in 2013, 25.2%, and in 2018, 27.4%. The two largest groups of migrants are from the UK (265,000 people) and China (144,000). Perhaps 1 million New Zealanders live overseas, including one in six Māori.

New technology

A lot of media attention has been focused on projects and proposals for “zero-emission” aircraft, of which the three main contenders are battery electric, hydrogen electric, and hydrogen combustion. (Emissions would be very low or zero during flight; lifecycle emissions including building the aircraft and making the fuel and providing renewable energy for it would not of course be zero.)

Nice computer graphics from Airbus, but irrelevant to the subject of this blog post.

There are two big problems with relying on new technology to deal with aviation emissions. The first is that the new aircraft do not exist yet, so the uncertainties are large and the time spans involved mean that industry and government scenarios do not envision much role for them out to 2050. The second is their energy requirements. A study by Ian Mason considered the prospects for hydrogen aviation, finding that 42 TWh of electricity could be needed by 2050—equal to New Zealand’s entire current supply. In addition, New Zealand would be attempting to replace all the fossil fuels used in land transport, and a lot of those used in industry, with electricity and/or hydrogen at the same time. Electrolysers tend to be placed where the fuel is needed, indicating a need for a 3800 MW electrolyser at Auckland airport, a power demand equivalent to about 6 times that produced by the Manapouri power station. (About 200 MW of electrolysis is currently in existence worldwide.) Power could be provided, for example, by 14,000 MW of wind turbines, i.e., 63 copies of the Turitea wind farm that is currently under construction at a cost of $370 million.

In other words, the energy requirements are extreme.

The lion’s share of many aviation pathways focus on sustainable aviation fuels (SAF). In 2019, 0.05% of global aviation fuel was biofuel, made from food crops and waste food such as tallow and used cooking oil. These are limited in supply. Therefore, pathways with high levels of SAF look to other feedstocks, especially (for New Zealand) wood waste and logs. However, there are no such plants in commercial operation. A report from the ICCT concluded that the EU could be capable of producing 2 Mt a year of wood-based biofuel by 2035, slightly more than New Zealand’s 2019 consumption of jet fuel. Closing the apparent gap—a factor of 100—will need close attention.

New Zealand is in the process of implementing a biofuel mandate for land transport, with a target of 9% biofuel by 2035. An initial study estimates that a $520 million plant could produce 57 million litres of fuel per year, 0.7% of New Zealand’s liquid fuel consumption, and that there is enough feedstock available for 20 such plants. A wood-to-fuel plant is presently under construction in the US by Lanzatech.

E-fuels, made directly from water and carbon dioxide (sourced from the air or from flue gases) and a lot of renewable electricity, can potentially be supplied in any amount. Some small trial plants are under construction in Europe. The obstacles are cost and (if the industry were to scale up) renewable electricity supply. The ICCT estimate that at 2 euro per litre support, the EU could produce 0.23 Mt a year of e-fuels by 2035. Their cost, five times the current price of jet fuel, would increase the price of travel while also reducing emissions at the source. The energy requirements are about twice that of hydrogen.

An ambitious scenario for 2035 for aviation SAF for New Zealand would involve two $520m wood-based biofuel plants (producing 57 million litres a year each) and one 100 MW e-fuel plant producing 40 million litres a year. Together they would provide 8% of New Zealand’s aviation fuel at 2019 levels of demand.

Although New Zealand has good potential resources of both renewable electricity and of feedstock for biofuels, significant capital investment and advance planning would be required to exploit them. Nevertheless, sustainable aviation fuel mandates open up pathways in which the higher costs of sustainable fuels lead to greater focus on efficiency and lower traffic growth.

The obstacles in the way of a technological solution to aviation emissions are formidable. In addition to cost, technological readiness, feedstock supply, and environmental side-effects, there are difficult timing issues. On one hand, emission reductions are needed now, but the alternatives are not ready; on the other, it is hard to reliably forecast the future cost of different solutions in order to make the necessary decisions now.

The industry view

Air New Zealand has taken an increasingly strong line on sustainability, which has been maintained and even strengthened during Covid. Their 2021 sustainability report was the first to outline a pathway to reach net zero by 2050. It involves 75% passenger growth by 2050, with net zero to be achieved by 20% of the emissions cuts coming from new conventional aircraft; 20% from zero-emission aircraft; 50% from SAF (implying an 86% SAF mandate); 2% from operations; and 8% from offsetting.

They see a need for strong government action to establish a domestic SAF industry, first based on forestry residues with a domestic plant running by 2027, then on waste, then (from 2045) on whole logs and e-fuels, with steady progress ensured via an SAF mandate. The head of Air New Zealand’s sustainability advisory panel, Jonathan Porritt, commented that

New Zealand will always be a price-taker. By 2030, it will be the big players in the industry who will be determining that price. The only way of managing that risk is for New Zealand to ensure its own, indigenous SAF capability—and that means taking big decisions in a clear and accountable way over the next couple of years.

The Ministry of Business, Innovation, and Employment will advise on an aviation SAF mandate in 2022, with the mandate proposed to start in 2025.


The entire topic of offsetting and its role in climate solutions is controversial. For example, Wim Carton discusses the supposed carbon, geographical, and temporal equivalences between positive and negative emissions, and concludes that climate justice requires their uncoupling:

Increasing carbon in terrestrial sinks simply replaces carbon that has been lost to the atmosphere over past centuries. Fossil carbon, on the other hand, is permanently locked away. Thus, burning fossil fuels moves carbon from permanent storage into the active carbon cycle, causing an aggregate increase in land, ocean, and atmospheric carbon. Once added, this additional carbon cannot be removed through natural sinks on time-scales relevant to climate mitigation.

In addition, on purely physical grounds, Kirsten Zickfeld concluded that a CO₂ emission into the atmosphere is more effective at raising atmospheric CO₂ than an equivalent CO₂ removal is at lowering it.

For these and other reasons, the NGO Climate Action Tracker recognises gross emissions only.

The issue is particularly acute for New Zealand, where mitigation pathways require forestry to rapidly and continuously increase to 2050 and beyond. Emissions from the first half of the century would be stored above ground and maintained by our descendants in the second half of the century.

EU Fit for 55, UK Jet Zero, and the IEA Net Zero scenario

Under “Fit for 55”, the EU will phase out free ETS allowances for intra-EU aviation (currently covering about half of such travel) over 2024–2027, and reduce the emissions cap of the whole ETS faster. They will tax jet fuel for intra-EU flights from 2023, with the tax rising to $250/tCO₂ by 2033. An SAF mandate will rise from 5% in 2030 to 20% in 2035 and 63% by 2050, for which only waste wood and fats and e-fuels will qualify.

Their model forecasts a baseline growth in emissions of 20% over 2015–2050, with the new proposals reducing emissions by 52% overall.

The UK’s Jet Zero has a headline goal of net zero aviation by 2050. On top of traffic growth of 54%, reductions come from demand reductions 9%; efficiency gains 36%; zero emission aircraft 4%; SAF 14%; and offsets 37%. SAF proposals are oriented around the establishment of a very large domestic industry, with 25–125 large SAF plants in the UK by 2050.

The International Energy Agency released an influential net zero study in 2021 . For aviation, their scenario involves business travel and flights longer than 6 hours held at 2019 levels; regional flights shifted to high-speed rail where feasible; total travel to increase 70% between 2019 and 2050; advanced biofuel and e-fuel use to reach 50% by 2040 and 78% by 2050; governments to define their SAF strategies by 2025 at the latest; and carbon prices across all advanced economies rising to US$130 by 2030 and US$250 by 2050.


Aviation growth and airport expansion go hand-in-hand.

In New Zealand, Auckland Airport’s long-held plans for a second runway have been put on hold by Covid, but a $1 billion airport redevelopment will go ahead. Wellington Airport is in the process of expanding; the first stage has been approved and is now under a court challenge. Christchurch Airport is proposing to build an entirely new international airport in Tarras, Otago, to serve the Queenstown–Wanaka region, again prompting environmental concerns. All three airports are partly publicly owned.

In the UK, the Balanced Net Zero pathway of the UK CCC requires no net airport expansion in the UK; but eight airports are currently planning expansions.


The growth of aviation has been tightly linked to the growth of tourism, both in New Zealand and worldwide. If aviation continues to grow, tourism will likely either continue in this role or become even more dominant. Through the 2010s the marketing of tourism continued to evolve, with talk of adventure and bucket lists for the upper middle classes in developed countries, and privilege and luxury for those on the highest incomes.

In January 2022, James Higham of the University of Otago co-edited a special issue of the Journal of Sustainable Tourism, writing in the introduction (“Code red for sustainable tourism”):

Governments need to take a leading responsibility, but we cannot currently expect this to come from national tourism administrations. […] Tourism administrations are guided by two key performance indicators: volume of (international) tourists, and volume of expenditure. Until their mandate changes, and they are required to develop metrics of success aligned with the Sustainable Development Goals and the Paris Agreement, any change will only happen as a result of other government departments that have a sustainability remit, particularly from those in charge of transport, energy and climate.

In 2021, the Parliamentary Commissioner for the Environment, Simon Upton, made tourism aviation emissions one of four key foci of a report on sustainable tourism. In view of the particular political and practical challenges of the sector, he made two modest recommendations: one, to incorporate an emissions price into the cost of air travel from New Zealand, along the lines of the UK’s departure levy, with revenues directed to decarbonisation R&D and Pacific climate finance; and two, to seek a plurilateral agreement, such as a climate club. So far, this has gone no further.

Stefan Gössling has proposed three areas of action for national and regional tourism bodies. First, to lower emissions by focussing on closer markets, longer stays, and lobbying for regulation of aviation emissions. Second, to add value by promoting local and year-round activities. Third, to reduce financial leakage due to franchises, foreign ownership, travel booking sites, credit cards, and frequent flyer programs.


The natural experiment of Covid has revealed the startling availability of substitutes for flying, including flying less, videoconferencing (which, although not an exact substitute, has perhaps connected more people than flying ever did), substituting domestic for international tourism, substituting local tourism for distant domestic tourism, and substituting land transport for domestic air travel.

The land transport options are private vehicles or public transport, bus and train.

Low-occupancy private cars are at present even higher-emission than flying and likely to improve only slowly on a fleet-wide basis. This option is high-emission for the vast majority of car owners, and not available at all for people who do not own a car or drive.

Regional public transport is limited to buses and trains. The passenger rail network, which had eight lines totalling 2700 km in 2001 and shrank to four lines and 1340 km by 2020, now just has three short routes left, Wellington–Palmerston North, Wellington–Masterton, and Hamilton–Auckland, totalling 348 km. For tourists, there is still the train from Christchurch to Greymouth. A private coach network still exists, but suffers from infrequent service, poor quality, substandard terminals, lack of connectivity, and lack of integrated ticketing.

Until the entire inter-regional transport system is considered as a whole, it will not be possible to assess the case for specific interventions such as rail electrification, resurrection of regional passenger rail, or an upgrade to higher-speed trains.

Emissions pricing

In New Zealand, domestic aviation is included in the Emissions Trading Scheme and in the carbon budgets. The first budget period covers 2022–2025. Prices rose from $39/tCO₂ to $85/tCO₂ in the year to 18 February 2022.

Therefore, one view is that no further action is needed on domestic aviation.

However, a recent review by one of us comes to an opposite conclusion, namely that emissions pricing can’t do it alone. The behaviour change and technological transitions are too demanding in the required time frame, and prices are unlikely to be allowed to rise high enough. Complementary policies can deliver emissions reductions in a fairer and more orderly way, even under a cap on emissions.

For example, the EU is proposing to use both an SAF mandate and a fuel tax, in addition to a strengthened ETS and a cap on (EU) emissions. European support for rail is also linked to reducing intra-EU aviation. The IEA’s net zero pathway also involves significant carbon pricing along with SAF and traffic regulation.

The tax advantage of international aviation (no ETS charge, no GST, no fuel tax) is an obstacle to emissions reduction. The legal obstacles to revising it were canvassed by the Parliamentary Commissioner for the Environment. They were a primary reason for his recommendation of a distance-based air passenger duty, as a pricing option that is legally available immediately. It could form the first step in a more comprehensive pricing regime. And now that the EU is proposing to tax jet fuel the options politically open to other countries may increase.

The distribution of air travel

Air travel is strikingly unevenly distributed. A large study of EU household emissions found that 90% of EU households have air travel emissions averaging 0.1 tonnes per person; 9% average 0.8 tonnes; and the last 1% average 22.6 tonnes. The authors write that this “confirms air travel as a highly carbon-intensive luxury” and describe transport as “one of the most unequally distributed and the strongest drivers of the carbon footprints of the rich”.

The implication is that other things being equal, an increase in inequality will be associated with an increase in flying, and in increase in GDP will be associated with a disproportionate increase in flying.

Statistics New Zealand are preparing a study of the distribution of emissions of New Zealand households.

From a study in Nature Energy of the role of high socio-economic status (SES) people in the climate crisis:

High-SES status people often lead hypermobile lives, travelling by air for private and work-related purposes induced by income, business travel paid for by employers and expectations associated with status, work and ownership of multiple homes. Although the behavioural plasticity of air travel is under-researched, it may be substantial for high-SES people given the likelihood that the marginal benefits of each flight are lower for them than for lower-SES people who may fly only rarely to visit family. Changing social norms around hypermobility therefore appear to be an important potential lever to decrease GHG emissions from air exposure and the glamorisation of high-SES people), as owners and managers of organisations, and through lobbying.

The problem is not just that the high emitters have to pay more towards the transition. The harder problem is that they actually have to reduce their emissions. Ivanova and Wood regard a target of 2.5 tonnes per person by 2030 as consistent with the Paris agreement. That means average emissions falling by 70%. But the bottom half of emitters can’t reduce by very much at all, which means the top half have to do more. The situation is particularly extreme in aviation: only flyers can reduce their aviation emissions.

Flying less

Most modern economists and policymakers do not engage in the question of what consumption is luxurious, wasteful, or unnecessary . On the other hand, some go further and argue that overconsumption is built in to capitalism, and that therefore reducing emissions will require significant changes in work, production, consumption, advertising, and social norms.

The widespread realisation of ecological overshoot and its catastrophic consequences, as well as humanity’s acceleration of unsustainable resource use when confronted with the reality of climate change, has prompted a wide range of responses. One framework is the “degrowth” movement, which calls for a decrease in global resource consumption until it reaches sustainable levels.

A decent standard of living actually requires very little energy. A global study describes a lifestyle involving 5000–15000 km of annual travel per person, of which 1000 km is by air, and total energy consumption of just 15 GJ/person/year, one-twelfth of New Zealand’s present consumption.

One of that study’s authors, Julia Steinberger, Professor of Ecological Economics at Lausanne, is an active voice in the climate movement:

In the UK, the “Jump” campaign asks people to sign up to six key lifestyle changes, one of which is to limit flights to one short-haul ( < 1500 km) return flight every three years, or one long haul return flight every eight years, levels derived from a study of urban lifestyles compatible with 1.5 ºC.

Applying the “avoid, shift, improve” framework to New Zealand aviation would likely reveal that the greatest opportunities lie in “avoid”. “Shift” also has a role in domestic aviation, for example by improving land-based low-carbon public transport. As we have learned from Covid, it is possible to avoid most international air travel with unexpected ease, whereas avoiding such a large proportion of emissions so quickly from food, housing, and goods and services without disastrous side-effects would be impossible.

James Higham examined aviation in light of the UN Sustainable Development Goals, noting that ICAO and the aviation industry claim that aviation contributes positively to almost all of the Sustainable Development Goals yet ignore the two most important factors, growth and emissions. Higham writes:

… aviation is deeply embedded in not only the economic, but also the social, functions of global capitalism. Because air transport is so “tightly bound up with the reproduction and expansion of capitalist societies”, there has been a reluctance to act on the environmental impacts of aviation. Rather than confront the problem of aviation emissions, the macro-level sociotechnical regime has been consciously developed to perpetuate growth in air travel.

It is difficult to define what flights are ‘essential’. The Ngā Tūtohu Aotearoa wellbeing indicators are monitored by Statistics New Zealand. While 81% of the population reported high overall life satisfaction in 2018, this rose to 84–86% in 2020–21, during a time when international travel was almost impossible (international passenger numbers fell 97.6% in the year to March 2021 compared to the previous year.) A further measure, on ‘leisure’, is under development: it will measure people’s amount of leisure time and their satisfaction with their amount of leisure time. It seems unlikely that international travel will impact on this score. Under the Material Wellbeing Index, ability to have a holiday away from home once a year scores one point (out of 35 points in total).

Noel Cass, in a study for Oxford University’s Centre for Research into Energy Demand Solutions, consider the role of curbing excess energy consumption in a fair transition. After comparing ten possible definitions of ‘excess’, they conclude that

excess is whatever people can agree it is, based on ideas of ‘fairness’ and ‘just’ levels of consumption that can be rationalised, defended, and justified to others…any policies that are used to target excess consumption and excessive consumers must be similarly reasonable and justifiable, based on the principles of deliberative democracy and exploring options, impacts, and fairness with members of the public.

What is a fair share for aviation emissions?

There is no universally agreed approach to this question.

One possible avenue follows the carbon budgets of the IPCC . Taking the remaining global carbon budgets for 1.5 ºC and allocating aviation 2.4% of global CO₂ leaves a carbon budget for global aviation of 9600 MtCO₂, or about ten years of flying at 2019 levels.

In 2019, New Zealand was responsible for 0.54% of global aviation emissions. Retaining this share and assuming aviation recovers to 2019 levels by 2024, followed by a decline to net zero in 2050, would see the carbon budget for 1.5 ºC exhausted by the early to mid 2030s.

Under the carbon budget approach, very sharp reductions in emissions are needed. However, earlier action makes meeting the budgets easier. Ensuring that 2019 levels are never regained would make meeting carbon budgets significantly easier.

Fairness towards future generations points towards relying as little as possible on carbon sequestration (whether by forestry or CCS) and focussing on absolute emissions reductions.

Fairness to all New Zealanders requires taking the (at present) highly unequal distribution of air travel, and the luxury and inessential nature of some air travel, into account, implying that aviation emissions should reduce more rapidly than other, more equal and more essential sectors.

In place of these considerations, the dominant narrative so far has been that, first, aviation is “hard to abate”; second, that it should be allowed to grow and to consume an ever larger share of gross emissions; and third, that it should not be subject to the “polluter pays” principle.

The experience of Covid indicates that even an almost complete stop to international aviation had surprisingly little effect on the economy (GDP grew 3.4% from 2019 to 2021) or effects on wellbeing. However, there are confounding effects for both of these, namely government economic stimulus, social solidarity, and knowledge of the health risks of travel. Substitutes including telecommunications, domestic tourism, and local tourism were adopted.

Taken together, these considerations imply that a naive “net zero by 2050” pathway, with steady traffic growth and heavily reliant on offsetting and nonexistent technology, would not sufficiently fair or ambitious for New Zealand.


The three main factors that will affect aviation emissions over the next 30 years are efficiency, alternative fuels, and total travel. Zero-emission aircraft will play a limited role.

Efficiency gains could be encouraged by carbon pricing, by an SAF mandate, or by banning the operation of high-emission aircraft models.

There is wide disagreement over the potential for alternative fuels and for the speed with which they can be supplied. Proposals for SAF vary widely and rely on technology which is not yet in commercial use.

Total travel also varies widely in the different pathways. The high growth scenarios are dubious for a number of reasons.

  1. They rely on significant amounts of offsetting (which is not sustainable in the long term) or permanent carbon dioxide sequestration (which is unproved at commercial scale)
  2. They rely to some degree on technological solutions, which may not be available quickly enough.
  3. They have not been found to be consistent with the Paris Agreement, nor to demonstrate its principles, including fairness, responsibility, capability, and highest ambition.
  4. They do not take into account the need to reduce fossil fuel burning drastically in the coming decade.
  5. They rely on a naive interpretation of the claim that aviation is “hard to abate” which has not been sufficiently justified or interrogated—for example, by comparing to other sectors which are also challenging technologically. As things stand, climate safety points towards phasing out “hard to abate” sectors where possible.
  6. Other things being equal, a net zero pathway with high growth will result in greater total emissions than a net zero pathway with low or negative growth. Under a finite carbon budget, it is the total emissions that are relevant, not the endpoint.
  7. A net zero pathway with high growth involves devoting greater total resources (of renewable energy, land, and construction of SAF facilities) than a pathway with low or negative growth. In a transition in which all of these resources are constrained, there is a need to prioritise resources.
  8. The high-growth scenarios, which generally show a continued acceleration of growth continuing past 2050, do not address fundamental questions of sustainability, even if net zero were to be reached.
  9. They do not take into account the distribution of aviation and its resulting implications for climate justice.

The past two years have seen numerous international bodies have aligned behind a vision of net zero aviation by 2050.

The main areas of difference between industry- and non-industry-led scenarios is that the former involve more growth—they often consider growth rates as given and not as a key variable—and reject emissions pricing. Some industry proposals seek government funding and subsidies. Some also reject regulation and rely on voluntary action and aspirational goals.

While pricing international aviation is difficult, which would by itself tend to point more towards regulation of emissions, some jurisdictions are now starting to consider it. Most likely, a combination of pricing and complementary policies will be needed .

A national action plan should include consideration of the following factors.

  1. Adoption of the “avoid, shift, improve” framework;
  2. emissions pricing and the “polluter pays” principle;
  3. where pricing is not achievable, regulation of emissions and emissions intensity;
  4. the non-CO₂ effects of aviation;
  5. the distribution of flying in a climate justice perspective;
  6. the availability of substitutes, and the national strategies for those substitutes (e.g., regional public transport);
  7. coordination with the tourist industry;
  8. the rate of growth or degrowth;
  9. the role of airports;
  10. timely implementation;
  11. emphasis on proven technologies, such as using the most efficient existing aircraft filled as much as possible;
  12. the lifecycle emissions and resource requirements of SAF, including land use, renewable energy, and facility construction;
  13. a fair share for aviation emissions with reference to the whole population and economy, not just to frequent flyers and the aviation industry; and
  14. the transition to true sustainability respecting the rights of future generations.

Two key events of the past half decade reinforce the urgency of the task. The first is the proven ability of the New Zealand aviation industry to increase emissions at a staggering rate when unregulated, as observed from 2015 to 2019; the second is Covid. Ensuring that aviation emissions remain permanently well below 2019 levels requires urgent action, but would make the longer-term task significantly easier.

Read the full report.

‘We do all need to change our ways of living’: Interview with David Hall on climate change and democracy

Dr David Hall is a political theorist with a research focus on climate change, sustainable finance, and land use. He has a DPhil in Politics from the University of Oxford and currently is Senior Lecturer at the School of Social Sciences and Public Policy, AUT University, and Chair of the Vice-Chancellor’s Sustainability Taskforce. He is also co-founder of Mōhio’s Climate Innovation Lab, a partnership with ANZ which designs novel financial instruments to enable climate action. His most recent book is A Careful Revolution: Towards a Low-Emissions Future (BWB Texts). He was interviewed by Robert McLachlan at the Auckland Art Gallery on 12 January 2022.

Robert McLachlan: Where do you see New Zealand’s climate response sitting right now?

David Hall: I see us still, in the international context, as a follower, and I think we’re in a phase of doing catch-up. The previous government dragged its heels more than the current government, which is now picking up on policies that other countries have implemented in the meantime. So there’s not much in the way of leadership, not much in the way of path-breaking, but there is policy transfer underway, with New Zealand adopting some of the trends from overseas, especially from Europe. This includes the Zero Carbon Act, which is one of many climate framework laws around the world, as well as the Clean Car Discount, the vehicle emissions standards, and so on.

Robert McLachlan: There are some new things emerging. There are youth climate activists and people interested in new urbanism. But there’s also a much bigger group of people who are happy with things the way they are, and may not realise the scale of the changes that need to be made. And the government has to thread their way through this.

David Hall: It is challenging. It’s easy to underestimate how difficult it is for politicians to navigate that space. Because they are relying on being voted back in, they just can’t run too far ahead of the public. But the public is changing, and climate action is becoming more vigorous and urgent among some people. And there’s a latent impulse, a sort of weak desire for action amongst the majority of people. The people who are demotivated, or proactively against climate action, are a minority, but there’s a large swathe who are aware of climate change and have a general tilt towards doing something, but are easily displaced by concerns about cost and inconvenience and are reluctant to change their ways of doing things. That’s the challenge for politicians, how to bring that set of people along.

However, while I think that some people too easily criticise politicians for not running ahead of voters, our leaders can justifiably be criticised for not doing enough to persuade and convince that group of people that we do all need to change our ways of living. Someone like our current prime minister, who does have the gift of communication, hasn’t used her powers as much as she might have to bring people on board.

Some of the narratives in which we’ve understood climate action have been failed narratives. I suspect that most politicians haven’t had enough exposure to the more positive narratives around climate action. There’s been a prevailing narrative that climate action is largely a sacrifice; it’s been framed in terms of cost, of deadweight loss. But there is a growing appreciation amongst some economists that it’s an investment with tangible returns and a huge swathe of co-benefits, so that we can address a lot of other issues by moving to a low-emission economy. It shouldn’t all be framed in terms of losses and costs. It’s an investment in the future and an opening up of new pathways, of new ways of living on the planet.

There’s also a competition underway – this is perhaps more relevant for the bigger economies, like the US and China – that the fossil fuel-dependent economy is a sunset economy, whereas the renewable energy economy has a huge amount of growth ahead of it. New Zealand needs to orientate to that, especially around the supply of food, timber, and biomass. We face a major risk of falling behind and not embracing these opportunities. Other countries might start to dominate in sustainable food and sustainable timber.

Robert McLachlan: I suspect there are a lot of people who would be happy to see new electric buses, but not so happy if a bus lane appears where they used to drive. But if there are enough people on the buses, the balance could shift. Hopefully we will reach a social tipping point soon.

Do you see the New Zealand climate change community as mostly unified in terms of what we should be doing?

David Hall: Not at all! There’s a huge amount of disagreement, and I think that will only grow. But I see that as a positive thing. A decade ago, the focus of public debate was on whether climate change was an issue at all, whether it even existed. That debate is over, and we’ve moved on to the question of what we ought to do. That’s going to drive a lot more disagreement, because you’re connecting solutions to a wide range of political values and risk sensitivities. This depends on your political affiliation, your identity, your position in society, your class. All of these influence what you see as sensible solutions and what you see as urgent. Disagreement here is an inevitable part of trying to come to a solution in a democracy.

Robert McLachlan: Genevieve Guenther has commented that climate should be framed in terms of bad people trying to do bad things that damage everybody else. Who’s opposing climate action in New Zealand? Is that what we should be focusing on?

David Hall: I’m not sure I agree with that framing. I see the problem as lying in the systems we are operating in, not as the fault of the people operating in those systems. In the US context it’s more obvious who the enemies or adversaries are, there’s so much money going into lobbying from the fossil fuel industry, bad actors who are trying to prevent any sensible solution – although we do have a bit of that.

But Carl Schmitt’s friend/enemy distinction – where you identify your allies and your enemies, and then you try to vanquish your enemies – that we see playing out here in agriculture is unhelpful. All it’s done is polarize the issue and make farmers feel they are being attacked and that positive developments in that sector are ignored. Even the recalcitrant farmers are part of an existing system. They’ve taken on mortgages where banks have pressed them to intensify, and some practices have been the subject of government incentives. Sometimes they’ve been manoeuvred into unsustainable practices by the system they’re operating in. Changing the system around them requires engaging with banks, policy makers, and so on. An adversarial approach doesn’t help. In fact sectors like agriculture and urban form are particular unsuited to an adversarial approach, or to emergency politics where some authority swoops in and makes decisions on everyone’s behalf. You have to work with communities to reshape the system. That requires coalition building and more democratic approaches.

Robert McLachlan: The global climate and ecological crisis is so vast – is it better to focus on one little question, which focuses your mind and the public’s mind on a specific issue and possible solutions, or to look at the big picture? I see a lot of people arguing that we need to overturn all of modern society.

David Hall: We should do what we think will have the most impact. Some people are better at specializing and some are better as generalists. I’m a generalist, I like to operate between a lot of different areas, perhaps because of my background in geography and politics. My focus is on how to change the politics of climate change. That requires understanding how our institutions create different forms of lock-in, how new institutions can drive human behaviour in different ways, to understand politics and power and the negotiation between governments and peoples.

Robert McLachlan: We’re trying to persuade the public to be more in favour of climate action, but even persuading our colleagues is difficult. The New Zealand universities haven’t really been leading on this issue.

David Hall: No, they’ve been a huge failure. But like the farmers, academics are trapped in a system with certain incentives that drive behaviour. Just look at aviation – international conferences, research collaborations, sabbaticals – these are all rewarded by the system, which drives academics to do as much flying as possible. Similarly, if research funding isn’t set up to channel research activity toward solving public problems, then we end up with this gulf between academic activity and real world challenges, like climate change. All that said, there are some academics who’ve used their academic role to advance climate action in the sciences, social sciences and humanities, and we should be grateful for those efforts.

Robert McLachlan: In countries where the government is hostile to climate action, it’s recommended to focus on grass-roots activism and coalition building. Are we in the same position here? Is the climate movement too small to push for the changes that we need?

David Hall. Yes. Everywhere suffers from this. The crucial thing is that that movement is happening in many different spaces. In climate governance, there is an idea of ‘polycentricity’, that leadership occurs not just in central government but across a whole range of spheres – local councils, business groups, local communities, indigenous groups, civil society. Under the previous government, when there was a conspicuous lack of progress or ambition, this prompted leadership from other parts of society. We saw the emergence of Generation Zero, the Climate Leaders Coalition, the Sustainable Business Council, Pure Advantage. Now that polycentric movement is maturing, which makes it safer for governments to take the plunge.

Robert McLachlan: I would like to see more local successes, though. Getting involved in a local battle over a cycleway or something can be discouraging.

David Hall: While the current government has been more proactive and has advanced a lot of policy, it’s tended to be at the institutional level of rules and standards. We don’t see the fruits of that yet, because the impacts will play out over years and decades. On the bright side, this reduces the likelihood of worst-case scenarios where New Zealand just drifts into massively missing its targets. But on the negative side, we’re still not seeing the decisive actions on the ground that show concrete results, like controlling imports of SUVs, for instance, or declaring phase-out deadlines or making big spending commitments on research, development and deployment. And the reason is, of course, that those are the actions that can trigger really fierce political fights because there are immediate winners and losers that politicians will have to answer to at the next election.

Robert McLachlan: Turning to the global picture, as well as the challenge of addressing climate change, there’s also a lot of other weird stuff going on. Dangerous situations are developing in the traditional democracies. Is it just a coincidence that these things are happening at the same time?

David Hall: No, I don’t think it’s a coincidence. Representative democracy is losing its social licence, its own right to govern. In some places the social contract is dwindling to the extent that large swathes of people think their representatives have lost the right to make rules on their behalf. But climate action needs those rules. So on one hand it makes action difficult, but on the other hand it is an opportunity. Because there is a truthful critique here, that representatives have failed to defend the interests of “the people” in a number of different domains. It is more likely that issues like inequality and mortality are driving the revolts we’ve seen elsewhere, but I think climate change and protecting people from the growing dangers and risks of environmental degradation are part of that story as well, whether people explicitly think of that as a reason or whether they just respond to some of the negative effects like floods and droughts, the effects on their businesses and supply chains, and the indirect contribution to poverty and economic disruption.

Robert McLachlan: People are right to be worried.

David Hall: Right. But political representatives have clearly failed to respond to these challenges. So if some of this unrest and discontent forces representative democracy, or democracy in general, to try to better achieve its own objectives in representing the will of the people and protecting people from these risks, then perhaps that will help is to create new institutions that do respond better. That’s the opportunity.

We see that most visibly in the new ideas about forms of invigorating democracy such as through citizens’ assemblies. It’s not a coincidence that we see that conversation now. And indeed, some states like France are using citizens’ assemblies as a way of responding to that criticism, following the gilets jaunes protests. There is an opportunity there. It’s a race for us who believe that we can respond to climate change in a democratic way to design new mechanisms and to implement these new mechanisms before the authoritarians and the despots exploit this opportunity to implement top-down and arbitrary institutions that they prefer.

Some sad clowns contemplate climate change at the Auckland Art Gallery.

New Zealand’s 2021 climate action

By Robert McLachlan

2021: the fourth year of the Labour-led government; the first in which it governs alone; the second year of the Covid pandemic; the last year before the Zero Carbon Act kicks in for real. What was achieved for the climate?

In terms of actually cutting emissions, – like removing petrol cars and coal boilers – not a lot. Apart from the Covid-induced slowdown, it’s unlikely that emissions have started falling. But changing the entire energy system takes time and preparation. 2021 was a year in which more ducks got in a row than ever before, some of them ducks never before seen in these parts.

Let’s check out those ducks and hear them squeak.

Duck 1: Renewable energy, especially solar

If 2019 was the end of a long wind drought, 2021 was the year in which solar power finally appeared. 

Before this year, New Zealand’s largest solar farm was Watercare’s 1 MW array, opened in October 2020.

Then in March, Kea Energy’s 2 MW solar farm in Marlborough (with 2-sided, sun-tracking panels!) was mostly completed.

Kea Energy's solar panel farm covers four hectares in the Wairau Valley.
Kea’s solar farm. Image: Kea Energy

In May, Lodestone Energy announced plans for 160 MW of solar across five locations in the upper North Island, to be built over 2021–2023.

In June, Kapuni Energy’s 2 MW solar farm in south Taranaki was completed.

In July, Far North Solar Farms kicked off their first 10 MW solar farm, Pukenui, in Northland, and announced plans to build 1000 MW by 2025.

In August, Genesis Energy announced a joint venture for 300 MW of solar farms, to be built over the next five years. It’s not clear what form the joint venture will take, as until now Genesis has declined to build any renewable generation itself, but has talked about buying renewable energy from others.

In December, Christchurch Airport announced a 150 MW solar farm, 30 MW of which will be built initially.

These farms are small compared to what is being built overseas, where 500 MW solar farms are now common, and small compared to what we’ll need in the future – perhaps 20,000 MW by 2050, which sounds like a lot, but it’s how much Australia has built in the past five years – but they are much larger than anything seen here before now. 

The combination of falling solar costs and increasing certainty that the government is determined to cut emissions seems to have finally done the trick. Solar now costs about 7c/kWh to build, about the same as new wind or geothermal power. 

Australians have been installing staggering amounts of home rooftop solar. We’re not seeing that here yet, although the combination of falling costs and rising electricity prices are bound to have an impact soon. A home solar array now costs $8000, and earns about $800 a year for the owners.

Some world leaders in rapid solar roll-out. It’s possible to scale up the solar industry rapidly and cheaply to add 2% of electricity per year. For New Zealand, that would mean building about 300 MW each year.

Less was happening in other areas, although stage 1 of the Turitea wind farm was progressively switched on, and in February, Meridian approved construction of the 176 MW wind farm at Harapaki near Napier.

Also in February, Contact Energy decided to build the 152 MW Tauhara II geothermal plant. This had been suspended last year because of uncertainty over Tiwai Point closure, which in January was delayed to 2024. Although better than coal or gas, the plant will emit 170,000 tonnes of CO2 a year, a point that was scarcely considered ten years ago when consent was granted.

In November, the second offshore wind energy conference was held in Taranaki, home of plentiful wind and shallow seas. (See the slides of the talks.)

So far, none of this has led to any coal or gas plants being decommissioned. That should happen soon. 

Duck 2: Coal angst

Mainstream and social media were fired up during the year by the massive increase in coal burning for electricity. Many pointed at the immediate cause, namely low lake levels, rather than the longer-term problem of a failure to build renewable supply and to phase out fossil fuels entirely. To the public it seemed to indicate a flaw in the whole idea of electric vehicles (Indonesian coal!!!), but at least the basic idea that coal is bad seems to have been understood.

As the lakes filled and the new wind farms switched on, the problem receded, hopefully never to return. 

Not what you should be seeing in a climate crisis. (Source: MBIE)

Duck 3: Transition plans appearing

In February, the Climate Change Commission released their draft advice, containing the carbon budgets out to 2035 and suggested pathways for achieving them. In November, the government responded, not with a plan as they had been required to do, but with an “Emissions Reduction Plan Discussion Document“. The plan itself has been delayed until May 2022. The document was criticised as half-baked. Only the transport section was fully detailed, probably because the Ministry of Transport had been hard at work for a while, releasing “Hīkina te Kohupara – Kia mauri ora ai te iwi: Transport Emissions: Pathways to Net Zero by 2050” in May. We’re starting to hear the creaking of some very large and interlocked wheels as our entire society prepares to change direction.

Each time a report like this appears, or indeed, any climate action at all is proposed, Matt Burgess from the New Zealand Initiative (formerly the Business Roundtable) comments that the suggested actions will not cut emissions by even a single tonne of CO2, because emissions are capped in the Emissions Trading Scheme. The argument is that any emissions cut in one place will be permitted to be emitted somewhere else. I wonder just what actions he thinks would in fact cut emissions, if the argument applies so universally. David Hall and I took apart his argument in a study of the international experience of emissions trading, which finds that it’s just one part of the whole system and cannot work just by itself. (David also wrote this week that Matt Burgess formerly worked for Charles River Associates, an economics consultancy that played a pivotal role in weakening, defeating, and delaying US climate policy since the late 1980s.)

Just to remind you of the scale of the problem, in April the figures for New Zealand’s 2019 emissions were released, and they were not good. They had shot up again, with CO2 emissions up 10%, or 3.8 million tonnes, in the three years 2016–2019.

Duck 4: Carbon price

After years in the doldrums, the carbon price in the New Zealand Emissions Trading Scheme finally took off, reaching $65 by the end of the year. (In Europe, prices reached 91 euros, $156.)

Source: Wikipedia

The whole market is rather complicated and mysterious. Some of these units have been purchased for future use, hedging against the expectation of higher prices. However, the government can choose to release fewer units in the future depending on the size of the stockpile, which would then send prices higher again.

In August, the government agreed to progressively raise the price ceiling each year, to reach $110/tonne in 2026. If the ceiling is reached, the government can choose to release extra units. This happened for the first time on 1 September, when 7 million units (permission to emit 1 tonne of CO2) were released, all of which were sold. The government may have to “pay back” these emissions in the future, although the cap on emissions doesn’t start until 2022.

In July, there was a consultation on reforming the free allocations given to certain export industries, such as tomato growers heating their greenhouses with coal.

But at a certain point, the Emissions Trading Scheme starts to make my brain hurt, so I’ll stop here.

Short version: higher carbon price = good; full picture not clear.

In July, Lawyers for Climate Action New Zealand filed for a judicial review of the Climate Change Commission’s advice, stating that the proposed emissions budgets are “irrational, unreasonable, and inconsistent with the purpose of the [Zero Carbon] Act”. The claim will be heard in the new year.

In August, All Aboard Aotearoa sued Auckland Transport and Auckland Council over a transport plan that fails to reduce emissions.

In December, the sustainable transport group Movement filed for a judicial review of the New Zealand Transport Agency’s $24 billion spending plan, on the grounds that it does not take into account their requirement to reduce transport emissions.

Duck 6: Action on car emissions, finally

The Clean Car Plan, the brainchild of Green MP Julie Anne Genter, which was to have brought in fuel efficiency standards and a system of CO2-based fees and rebates on new cars, was famously scuppered in 2020 by coalition partner New Zealand First. Freed of that shackle by the election, it resurfaced in June 2021 with a surprise twist: the rebates were front loaded and would come into effect immediately, in July. Market share for EVs jumped from 2% to 7%.

When we got to see the whole package, there was a further surprise: new emissions targets had be added for 2026 and 2027, and they are sharply lower. They will put us on track to end the import of petrol and diesel cars by 2030. The fossil parts of the car industry complained vociferously. The bill is now in parliament’s select committee, who will report back in February 2022.

Duck 7: Money for climate… next year

Between the motorway-heavy “NZ Upgrade” programme, announced in February 2020 just before Covid, emissions-heavy Covid stimulus spending (criticised by the Climate Change Commission), and one disappointing budget after another, government spending has not reflected the government’s supposed climate focus. One big win this year was the announcement in May that revenues from future auctions under the Emission Trading Scheme will be dedicated to climate change. Further details emerged this week: revenue of $4.5 billion over four years, and will go towards international climate aid, adaptation, and mitigation. Definitely a good start; in a year or two it should become clear whether emissions are tracking down fast enough.

Duck 8: Glasgow and the NDC

Despite heaps of (sometimes confusing) media attention on COP26 in Glasgow – if you missed it, you could do worse than watch Jonathan Pie’s very funny and on-point short film The World’s End – there was finally an agreement on the rules for international carbon trading. New Zealand has been relying on this, as just before COP26 our updated UN pledge was announced. Climate Minister James Shaw got the headline he wanted (“emissions to halve by 2030”) but the reality is somewhat different. Even Climate Change Commission head Rod Carr declined to say that the pledge met their advice.

There are so many potential problems with this, it’s hard to know where to start. For one thing, it is hard to imagine New Zealand spending billions of dollars to reduce emissions elsewhere while we continue to pollute at home. If I had to look for a silver lining, it would be that the target is a big step up on what we had before, and it will serve as an additional source of pressure to cut our own emissions.

So those are my eight ducks in a row, eight mostly hopeful signs of climate action in 2021. If it was all too cheerful and positive for you, don’t worry, the next post will look at some of the things we’re still overlooking and which I hope will receive more attention in 2022.

Happy New Year!

New Zealand’s Emission Reduction Plan

By Paul Callister and Robert McLachlan

Fifty years ago, on 26 November 1971, the film “Notes on a New Zealand City: Wellington”, directed by Paul Maunder, premiered on Wellington TV. The narrator asks if Wellington’s future will involve suburban sprawl, traffic, motorways, suburban shopping malls, and the decentralization of employment; or an alternative vision of medium-density apartments bringing a diversity of people into the inner city to live, work, and let their children watch the then-brand-new Cuba Street splash buckets. (And ride bicycles, many of which can be seen in the film.)

Although climate change isn’t mentioned in the film, the relevance could not be clearer. The extreme unsustainability of the path that was chosen fifty years ago is now understood in far greater detail. The necessity to rapidly and permanently reduce greenhouse gas emissions is merging with a renewed focus on the health, equity, community, biodiversity, and resource sustainability aspects of our cities, houses, transport, natural world, and industry – our entire way of life.

The Emissions Reduction Plan Discussion Document is full of good ideas. Public submissions close on 24 November. In our submission, we argue that, in addition, the plan should:

  1. Recognise that some individuals, companies, and activities are responsible for more present and historical emissions than others and that they should reduce their emissions more;
  2. Prioritise permanent gross emissions reductions over temporary reductions and temporary sequestration, and prioritise actions that hasten the phase out of the burning of fossil fuels for energy;
  3. As well as reducing the supply of greenhouse gas-intensive products, focus on reducing demand, via changes in consumption, shifts to low-greenhouse-gas alternatives, and the provision of public goods essential for wellbeing; and
  4. Reduce the carbon budgets so as to end to fossil fuel burning by 2050.

Why emissions pricing cannot do it alone

By David Hall and Robert McLachlan

There is strong agreement among economists that emissions pricing should play a central role in climate change policy. New Zealand has had a price on some carbon emissions through its Emissions Trading Scheme since 2010, although (COVID excepting) emissions have not yet fallen. Recently the scheme has been strengthened through higher prices, now NZ$65 per tonne of CO2, and a falling cap on emissions. It remains a central plank in our climate change response.

It’s been argued that the ETS should be our only mechanism to cut emissions, and that it will deliver the required cuts in the cheapest and most reliable way. The cap on emissions can even lead to absurd claims that any specific cut isn’t necessary, since total emissions will be the same regardless. (If you don’t fly, someone else will be free to emit that carbon in your place.)

Now the government, along the lines advised by the Climate Change Commission, has taken sides on this issue and is proposing a whole raft of policies for different areas, such as transport, industry, waste, and electricity. (Submissions are due by 24 November.)

There are now many countries with a price on carbon, and many of them also have a lot of non-pricing policies, like fuel efficiency standards. This provides an opportunity to look at the evidence of how well different approaches work. 

In a new working paper (Why emissions pricing cannot do it alone, Hall and McLachlan), we conclude that emissions pricing alone won’t trigger the necessary levels of behaviour change and technological transition quickly enough. Non-pricing policies do work, while pricing policies face obstacles to reaching high enough prices in a fair way. Consequently, we argue that the weight of evidence lies with using emissions pricing as part of a broader policy mix.

COP26: New Zealand’s new climate pledge is a step up, but not a ‘fair share’

By Robert McLachlan

As the Glasgow climate summits gets underway, New Zealand’s government has announced a revised pledge, with a headline figure of a 50% reduction on gross 2005 emissions by the end of this decade.

This looks good on the surface, but the substance of this new commitment, known as a Nationally Determined Contribution (NDC), is best assessed in emissions across decades.

New Zealand’s actual emissions in the 2010s were 701 million tonnes (Mt) of carbon dioxide equivalent. The carbon budget for the 2020s is 675Mt. The old pledge for the 2020s was 623Mt.

The Climate Change Commission’s advice was for “much less than” 593Mt, and the new NDC is 571Mt. So yes, the new pledge meets the commission’s advice and is a step up on the old, but it does not meet our fair share under the Paris Agreement.

The dark dashed line shows New Zealand's domestic climate goal – its carbon budget. The blue area shows a possible pathway under the old climate pledge, and the red area represents the newly announced pledge.
The dark dashed line shows New Zealand’s domestic climate goal – its carbon budget. The blue area shows a possible pathway under the old climate pledge, and the red area represents the newly announced pledge. Office of the Minister of Climate Change, CC BY-ND

It is also a stretch to call the new NDC consistent with the goal of keeping global temperature rise under 1.5℃.

True 1.5℃ compliance would require halving fossil fuel burning over the next decade, while the current plan is for cuts of a quarter.

Emissions need to halve this decade

Countries’ climate pledges are at the heart of the Paris Agreement. The initial round of pledges in 2016 added up to global warming of 3.5℃, but it was always intended they would be ratcheted up over time. In the run-up to COP26, a flurry of new announcements brought that figure down to 2.7℃ — better, but still a significant miss on 1.5℃.

As this graph from the UN’s Emissions Gap Report 2021 shows, the world will need to halve emissions this decade to keep on track for 1.5℃.

This graph shows that new and existing pledges under the Paris Agreement leave the world on track for 2.7ºC of warming. If recent net-zero pledges are realised, they will take us to 2.2ºC.
This graph shows that new and existing pledges under the Paris Agreement leave the world on track for 2.7ºC of warming. If recent net-zero pledges are realised, they will take us to 2.2ºC. UNEP, CC BY-ND

New Zealand’s first NDC, for net 2030 emissions to be 30% below gross 2005 emissions, was widely seen as inadequate. An update, reflecting the ambition of the 2019 Zero Carbon Act to keep warming below 1.5℃, has been awaited eagerly.

But several factors have combined to make a truly ambitious NDC particularly difficult.

First, New Zealand’s old climate strategy was based on tree planting and the purchase of offshore carbon credits. The tree planting came to and end in the early 2010s and is only now resuming, while the Emissions Trading Scheme was closed to international markets in 2015. The Paris Agreement was intended to allow a restart of international carbon trading, but this has not yet been possible.

Second, New Zealand has a terrible record in cutting emissions so far. Burning of fossil fuels actually increased by 9% from 2016 to 2019. It’s a challenge to turn around our high-emissions economy.

Third, our new climate strategy, involving carbon budgets and pathways under advice from the Climate Change Commission, is only just kicking in. The government has made an in-principle agreement on carbon budgets out to 2030, and has begun consultation on how to meet them. The full emissions-reduction plan will not be ready until May 2022.

Regarding a revised NDC, the government passed the buck and asked the commission for advice. The commission declined to give specific recommendations, but advised:

We recommend that to make the NDC more likely to be compatible with contributing to global efforts under the Paris Agreement to limit warming to 1.5℃ above pre-industrial levels, the contribution Aotearoa makes over the NDC period should reflect a reduction to net emissions of much more than 36% below 2005 gross levels by 2030, with the likelihood of compatibility increasing as the NDC is strengthened further.

The government then received advice on what would be a fair target for New Zealand. However, any consideration of historic or economic responsibility points to vastly increased cuts, essentially leading to net-zero emissions by 2030.

Announcing the new NDC, Climate Change Minister James Shaw admitted it wasn’t enough, saying:

I think we should be doing a whole lot more. But, the alternative is committing to something that we can’t deliver on.

What proper climate action could look like

Only about a third of New Zealand’s pledged emissions cuts will come from within the country. The rest will have to be purchased as carbon credits from offshore mitigation.

That’s the same amount (100Mt) that Japan, with an economy 25 times larger than New Zealand’s, is planning to include in its NDC. There is no system for doing this yet, or for ensuring these cuts are genuine. And there’s a price tag, possibly running into many billions of dollars.

New Zealand has an impressive climate framework in place. Unfortunately, just as its institutions are beginning to bite, they are starting to falter against the scale of the challenge.

The commission’s advice to the minister was disappointing. It’s being challenged in court by Lawyers For Climate Action New Zealand, whose judicial review in relation to both the NDC and the domestic emissions budgets will be heard in February 2022.

With only two months to go until 2022 and the official start of the carbon budgets, there is no plan how to meet them. The suggestions in the consultation document add up to only half the cuts needed for the first budget period.

Thinking in the transport area is the furthest advanced, with a solid approach to fuel efficiency already approved, and an acknowledgement total driving must decrease, active and public transport must increase, and new roads may not be compatible with climate targets.

But industry needs to step up massively. The proposed 2037 end date for coal burning is far too late, while the milk cooperative Fonterra — poised to announce a record payout to farmers — intends to begin phasing out natural gas for milk drying only after that date.

The potentially most far-reaching suggestion is to set a renewable energy target. A clear path to 100% renewable energy would provide a significant counterweight to the endless debates about trees and agricultural emissions, but it is still barely on the radar.

Perhaps one outcome of the new NDC will be that, faced with the prospect of a NZ$5 billion bill for offshore mitigation, we might decide to spend the money on emissions cuts in Aotearoa instead.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Kāpiti’s zombie airport

Wrong airport, but the picture was too good to pass up. Zombies from Extinction Rebellion protest the expansion of Wellington Airport, January 2019. Source: Zombie Apocalypse Monthly.

Kāpiti Coast Airport has hardly any flights and is living on borrowed time, but it just won’t die. Now a new report concludes that it “cannot remain operationally viable”.

By Paul Callister

In Glasgow, world leaders will be making big global decisions. These will have a major impact on whether we can avoid the worst of global warming. But it is also local decisions that will increasingly determine whether towns, cities and countries can reduce their emissions.

Throughout the world, aviation continues to get support from governments and local councils. It is also one of the sectors most difficult to decarbonise, especially as growth is still being promoted.

In New Zealand, regional air travel is subsidised in various ways. Sometimes it is through local authorities owning uneconomic airports. Or it can be through direct subsidies of airlines. This tends to spread the cost of air travel across the whole community, with the benefits mostly going to the better off members who also tend to have the highest emission profiles. Kāpiti Coast District Council provides direct support to Air Chathams. It now also wants to find ways to support the local airport.

Kāpiti airport needs to close. It is uneconomic and it is in the wrong place. It would be better suited to housing, which would help reduce local transport emissions. It will not get better. A report on the future of the airport undertaken in September 2021 by aviation consultancy group Lockie Airport Management highlights multiple problems.

Kāpiti Coast Airport

Despite this, the future of Kāpiti’s “ghost” airport continues to be contested. In a report back to submitters on Kāpiti’s Long-term Plan, the council states that ‘the future of the privately owned Kāpiti Coast Airport is uncertain’. If the council had undertaken a number of measures, including taking advice from airport experts, undertaking a full cost benefit analysis of airport operations, and had looked at small airport ownership around the world, or considered the airport’s alternative uses, they would have realised the future is absolutely certain. The uneconomic, and potentially unsafe, airport will eventually close. Medium to high density houses and apartments will be built on the site helping solve the housing crisis. These houses will be close to the centre of Paraparaumu and public transport, with already-established walkways and cycleways. This is the intensification the government is trying to promote. It is something a council, which has declared a climate emergency and which expresses concern about housing, should support.

Instead, based simply on a popularity contest, the council has indicated that it will explore ways to have a role in the airport’s future. They say this will include operating the airport under a lease or owning it in partnership. Exploring these options will further waste ratepayer money and delay the construction of desperately needed housing.

A key problem is runway length. The runway is physically 1450m in length, but technical constraints caused by roads, houses and terrain mean that there is only 1042m available for landing from the North, or 1187m for landing from the South. Practically, this limits the size of passenger aircraft the airport can accept. The largest was the Bombardier Q300s operated by Air NZ. These have 58 seats. However, they were not able to use all of them when flying from Kāpiti due to the available runway length. Air New Zealand are phasing these aircraft out in favour of the ATR72, which cannot realistically land with a full load of passengers at the airport. Air Chathams SAAB 340s are currently the largest aircraft using the airport at 36 seats. Other than Air Chathams and Air NZ, no other airline currently has a 30 seat plus aircraft capable of using the airport. This seriously limits opportunities for growth. Mayor Gurunathan has been reported saying that he does not want Air New Zealand back anyway.

Then there is Runway End Surface Area (RESA). The report says that the airport has the minimum allowable RESA length of 90m when the preferred length is 240m. The 90m RESA was re-approved in 2019. However, the report states a RESA below the recommended specification of 240m will not be approved again. The report says that other airports which have applied for reduced RESA’s since Kāpiti’s was approved have been unsuccessful. Extending the RESA is not practicable due to fixed flight path obstructions, a road, a number of private houses and a retirement village.

But it does not end there. There is an Obstacle Limitation Surface issue (OLS). The OLS is the required clear flight path on approach and departure to maintain suitable margins in poor weather and emergencies. There are around 900 noted objects to monitor spread over several hundred neighbouring properties. The objects are mostly trees but also chimneys, antennas, street lights and buildings, which add to the practical limitations on extending the runways and RESA.

A key lobby group for keeping the airport open is the aero club. Under the banner “Kāpiti Air Urban”, the club and a group of other airport supporters make some startling claims that are not supported by international evidence. An example is that by 2030 40% of aviation fuel will be from sustainable sources. In a paper on sustainable aviation fuels, Air New Zealand suggests a ‘drop’ in rate of 2.5% by 2025, reaching 25% by 2040. But, more problematically, the clubs’ activities do not provide the income needed to sustain an airport. There are plenty of good options for relocating the aero club, including the Foxpine airstrip, or even Palmerston North.

Kāpiti Air Urban clearly see innovation, including electric flight, solving the airport’s problems. This will be an argument we increasingly see. Why invest in regional passenger rail when electric planes are just around the corner?

Unfortunately for Kāpiti, electric planes also will not solve the economic viability or safety issues. Even if they eventually fill a niche in short hop air travel, they will not be common in our skies any time soon. Those under the flight paths will not welcome experimental planes flying over them. Far better that they fly out of Palmerston North or Wellington airports with flight paths away from major housing. These airports will also be able to fund the expensive charging infrastructure.

KCDC is now consulting on a growth strategy. It wants to house an extra 32,000 people by 2051. There will be some intensification, but the draft also suggests some greenfield development. The latter will inevitably lead to further sprawl and increase the region’s transport emissions just when we need to be reducing them.

The current airport owners, the Templeton Group, are housing developers. Instead of wasting money on impractical schemes to keep the airport open to support a high emissions industry, the council should be working with these developers to build the houses the district so badly needs.

Electric aircraft – coming soon to save us, or all hype and greenwash?

By Paul Callister and Robert McLachlan

Electric aircraft have arrived, but a lot has to happen to make commercial flights a reality. Can they live up to the hype, and can they reduce aviation emissions? We run the numbers.

It’s not easy to keep up with the rapidly-changing world of electric aircraft. It can look like a blizzard of breathless media coverage, corporate press releases, animations, venture capital deals and public offerings.

But as the launch dates creep closer, companies have been releasing more details, which makes it possible to see if the numbers add up.

Leaving aside Jetsons-like flying cars, three high-profile electric aircraft are Eviation’s Alice and Lilium’s Lilium Jet, both targetting commercial operations in 2024, and Heart Aerospace’s ES-19, targetting 2026. They are all startups, all with clean-sheet designs, all with substantial funding and order books.

While a lot of new technologies have to come together to make these planes fly, the most crucial part is the battery system. In this article we’ll use what we know so far about these three aircraft to see if they will deliver as promised.

The range equation

The range equation for battery electric aircraft is:


R is the range in kilometres;

eb is the specific energy of the battery in Wh/kg;

wb is the fraction of the total mass of the aircraft occupied by the battery system;

g = 9.81 m/s  is the acceleration due to gravity;

L/D  is the lift/drag ratio;

𝜂  is the efficiency of the battery-motor-propeller system; and

f  is the available fraction of the battery capacity.

Aircraft design is always a matter of compromises. Limitations associated with takeoff, cruise, landing, and range all point in different directions, while the economics depends on payload, speed, and fixed and operating costs for starters.

The Eviation Alice

Rendering of the Eviation Alice. Source: Eviation

Eviation announced a major redesign of the 9-passenger Alice in July. Crucially, they released some details of its battery: it stores 820 kWh and weighs 3720 kg, implying a specific energy of 220 Wh/kg. That’s for the whole battery pack and system, including temperature management.

For reference, the Tesla Model 3 has the highest specific energy battery pack now in widespread commercial use, at 160 Wh/kg. However, Tesla’s forthcoming 4680 cell, due in 2022-23, is aiming to achieve 380 Wh/kg at the cell level, which could mean that (allowing for framing, wiring, and cooling) 240 Wh/kg at the pack level is achievable.

On the other hand, the safety and cooling requirements are likely to be more stringent for planes than for cars. A lot of engineering has to happen between now and commercial flight to achieve the required weight and performance, to say nothing of reassuring the regulators about the risks of thermal runaway in the batteries.

Let’s use 220 Wh/kg for all three planes.

A high propulsion efficiency  is also crucial for range. Here we take , which requires each of the electrical and the propeller systems to be well over 90% efficient. This is optimistic but we can be sure that the engineers are aiming for something like this.

This gives the 9-passenger Alice, with a whopping 58.6% of its mass taken up by batteries, a range of 658 km. That’s an upper limit, since we haven’t taken into account any energy used by the other on-board systems, or the fact that climbing uses extra energy that is not all recouped on the descent. It’s less than the claimed range of 820 km, but still very impressive.

But not all that range is available for scheduled flights. Most regulators (e.g. in the US), require a 30 minute safety margin for daylight flights – about 165  km. (Night flights need 45 minutes reserves, and flights under Instrument Flight Rules need to be able to fly to an alternate airport plus an extra 45 minutes.) In addition, the battery capacity will degrade over time and the batteries will likely be replaced every 1500 flights or so, or at 80% state-of-health. With 30 minutes reserve and 80% state-of-health, the available range of the Alice is reduced to 360 km.

Eviation do have a bit of weight free. They could add more batteries while staying under the 8618 kg weight limit for this class of plane. However, diminishing returns set in, because unlike in a car, the extra batteries have to be carried aloft, which costs energy. Adding 50% more batteries would only increase the range by 16%.

Another critical task is to reduce the empty weight as much as possible. Eviation are claiming an empty weight of 1530 kg, to be achieved through the use of composites. There is only one small jet currently flying using composites, the 6-passenger Hondajet. It has a composite fuselage, aluminum wings, and an empty weight of 3379 kg. Eviation is aiming for less than half that weight.

Heart Aerospace’s ES-19

Heart Aerospace rendering of ES-19 aircraft for United Express.

Heart Aerospace have said that the battery of the 19-passenger ES-19 weighs 3000 kg. This puts the battery at 35% of the maximum take-off weight of 8618 kg.  This is also consistent with an 220 Wh/kg battery and a range chart released by the company. Together these give a range of 393 km, matching the company’s claim of 400 km. However, the reserve requirement now really eats into the possible routes, leaving only 150 km of range if a 30 minute reserve is needed.

The ES-19 is to be made of aluminum, which is cheaper, simpler, and heavier than composites. Heart Aerospace are aiming for an empty weight of about 3600 kg. The aluminum-framed Beech 1900, a popular 19-seat regional turboprop built from 1982 to 2002, has an empty weight of 4732 kg. A group of aircraft engineers at Linkoping University in Sweden have recently carried out a conceptual study of a 19-passenger electric aircraft very similar to the ES-19. It comes in at an empty weight of 3623 kg, achieved with extensive composites and no cost restrictions. Their more detailed model predicts a range of 284 km when 220 Wh/kg.

The Lilium Jet

Rendering of the Lilium Jet (Source: Lilium)

The Lilium Jet is something different. By far the highest-profile project of the three, Lilium recently went public, raising $585 million to add to the $375 million already on hand. It has 600 employees. The Lilium Jet uses an array of pivoting ducted fans rather than conventional propellers, allowing a vertical takeoff which quickly pivots to conventional flight. It doesn’t need a runway, but it has a lower weight limit (used for helicopters) of 3175 kg. The data they have released, taking into account that the batteries cannot deliver the power needed for landing when the battery charge is below 10%, give a range of 160 km, much lower than their aim of 250 km. (This is less than what is given by the battery range equation, because the ducted fans are less efficient than propellers and the hovering phase is extremely energy-intensive, while the fan design is a compromise between the cruise and hover phases.)

Lilium gets a range of 250 km by incorporating a battery with 320 Wh/kg at the cell level and discounting the weight of the packaging and thermal management, remarking that “the structural modules of the battery cells will be part of the empty aircraft structure.” That’s a pretty big task, since they are already aiming for an empty weight less than half that of the Hondajet.

So is it all hype?

Not quite. Batteries now starting production do deliver a useable range, if not quite what the companies are hoping. They will be aiming to get a foot in the door and to upgrade to better batteries as they become available. There are engineering hurdles to overcome, including minimizing weight and ensuring the reliability of the battery cooling system. There are political hurdles to overcome in certification. Existing modern aircraft are extremely safe, with only one fatal crash per ten million flights. Any battery issues during test flights will make regulators extremely wary. In addition, developers will also be asking for flexibility on fuel reserve requirements.

Or is it greenwash?

The media are certainly greenwashing like crazy, talking about “Decarbonizing air travel”. Electric aircraft will not be contributing meaningfully to decarbonizing air travel for decades, if ever – decades in which aviation emissions have to reduce steadily to achieve climate targets. Flights of up to 200 km contribute less than 1% of aviation emissions, and flights of up to 500 km, 5%.

The companies themselves have slightly different goals. They are hoping to revive short-range commercial aviation, which has been in decline due to its unprofitability and limited time savings. The idea is to offer a cheaper, more comfortable, and more convenient service than existing regional jets. Cheaper because electric, more comfortable because quieter and new, more convenient because they will use more and smaller airports. If this comes about, and especially if the routes lead to major airports connecting to long-range flights, electric aircraft would lead to increased emissions overall. If successful, they would also undermine lower-emission ground transport, such as trains.

Put it all together and it spells… New Zealand?

With all this in mind, it makes sense that New Zealand’s Sounds Air has been chosen as the Australasian launch customer for the ES-19. Sounds Air currently has six 9-seater and four 12-seater aircraft, flying to mostly smaller destinations such as Blenheim (population 28,000). A key launch route would be Blenheim–Wellington, just 75 km across Cook Strait, a famously rough stretch of water that channels the Roaring Forties. The flight would avoid a 3 hour 40 minute ferry ride. Such a route – head winds permitting – is ideal, and could lead to services at many similar island hops around the world.

Sounds Air might also find the regulators easier to deal with. New Zealand has been keen to welcome urban air mobility companies, who applaud its “flexibility” and have said they can do things in New Zealand they wouldn’t be able to do in the US.

Electric aircraft are at an exciting stage and may well find a niche. But they also risk turning into one more means of hypermobility for the rich, at a time when all forms of transport need to reduce in emissions, energy, and resources.

This article was first published at CleanTechnica. Read the original article.

Climate explained: how much of the world’s energy comes from fossil fuels and could we replace it all with renewables?

Shutterstock/Tsetso Photo

By Robert McLachlan

How are fossil fuels formed, why do they release carbon dioxide and how much of the world’s energy do they provide? And what are the renewable energy sources that could replace fossil fuels?

Fossil fuels were formed over millions of years from the remains of plants and animals trapped in sediments and then transformed by heat and pressure.

Most coal was formed in the Carboniferous Period (360–300 million years ago), an age of amphibians and vast swampy forests. Fossilisation of trees moved enormous amounts of carbon from the air to underground, leading to a decline in atmospheric carbon dioxide (CO₂) levels — enough to bring the Earth close to a completely frozen state.

This change in the climate, combined with the evolution of fungi that could digest dead wood and release its carbon back into the air, brought the coal-forming period to an end.

Oil and natural gas (methane, CH₄) were formed similarly, not from trees but from ocean plankton, and over a longer period. New Zealand’s Maui oil field is relatively young, dating from the Eocene, some 50 million years ago.

Burning buried sunshine

When fossil fuels are burnt, their carbon reacts with oxygen to form carbon dioxide. The energy originally provided by the Sun, stored in chemical bonds for millions of years, is released and the carbon returns to the air. A simple example is the burning of natural gas: one molecule of methane and two of oxygen combine to produce carbon dioxide and water.

CH₄ + 2 O₂ → CO₂ + 2 H₂O

Burning a kilogram of natural gas releases 15kWh of energy in the form of infrared radiation (radiant heat). This is a sizeable amount.

To stop continuously worsening climate change, we need to stop burning fossil fuels for energy. That’s a tall order, because fossil fuels provide 84% of all the energy used by human civilisation. (New Zealand is less reliant on fossil fuels, at 65%.)

Wind turbines on farm land in New Zealand
Wind energy is one of the renewable sources with the capacity to scale up. Shutterstock/YIUCHEUNG

There are many possible sources of renewable or low-carbon energy: nuclear, hydropower, wind, solar, geothermal, biomass (burning plants for energy) and biofuel (making liquid or gaseous fuels out of plants). A handful of tidal power stations are in operation, and experiments are under way with wave and ocean current generation.

But, among these, the only two with the capacity to scale up to the staggering amount of energy we use are wind and solar. Despite impressive growth (doubling in less than five years), wind provides only 2.2% of all energy, and solar 1.1%.

The renewables transition

One saving grace, which suggests a complete transformation to renewable energy may be possible, is that a lot of the energy from fossil fuels is wasted.

First, extraction, refining and transport of fossil fuels accounts for 12% of all energy use. Second, fossil fuels are often burnt in very inefficient ways, for example in internal combustion engines in cars. A world based on renewable energy would need half as much energy in the first place.

The potential solar and wind resource is enormous, and costs have fallen rapidly. Some have argued we could transition to fully renewable energy, including transmission lines and energy storage as well as fully synthetic liquid fuels, by 2050.

One scenario sees New Zealand building 20GW of solar and 9GW of wind power. That’s not unreasonable — Australia has built that much in five years. We should hurry. Renewable power plants take time to build and industries take time to scale up.

Other factors to consider

Switching to renewable energy solves the problems of fuel and climate change, but not those of escalating resource use. Building a whole new energy system takes a lot of material, some of it rare and difficult to extract. Unlike burnt fuel, metal can be recycled, but that won’t help while building a new system for the first time.

Research concluded that although some metals are scarce (particularly cobalt, cadmium, nickel, gold and silver), “a fully renewable energy system is unlikely to deplete metal reserves and resources up to 2050”. There are also opportunities to substitute more common materials, at some loss of efficiency.

Engineers working on a wind turbine
Building a new system will require energy and resources. Shutterstock/Jacques Tarnero

But many metals are highly localised. Half the world’s cobalt reserves are in the Democratic Republic of Congo, half the lithium is in Chile, and 70% of rare earths, used in wind turbines and electric motors, are in China.

Wasteful consumption is another issue. New technologies (robots, drones, internet) and economic growth lead to increased use of energy and resources. Rich people use a disproportionate amount of energy and model excessive consumption and waste others aspire to, including the emerging rich in developing countries.

Research analysing household-level emissions across European countries found the top 1% of the population with the highest carbon footprints produced 55 tonnes of CO₂-equivalent emissions each, compared to a European median of 10 tonnes.

Scientists have warned about consumption by the affluent and there is vigorous debate about how to reduce it while preserving a stable society.

One way of turning these questions around is to start from the bottom and ask: what is the minimum energy required for basic human needs?

One study considered “decent living” to include comfortable housing, enough food and water, 10,000km of travel a year, education, healthcare and telecommunications for everyone on Earth — clearly not something we have managed to achieve so far. It found this would need about 4,000kWh of energy per person per year, less than a tenth of what New Zealanders currently use, and an amount easily supplied by renewable energy.

All that carbon under the ground was energy ripe for the picking. We picked it. But now it is time to stop.

This article is republished from The Conversation under a Creative Commons license. Read the original article. Climate explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change. If you have a question you’d like an expert to answer, please send it to