John Raine, Michael Kelly and Bryan Leyland: WHY NEW ZEALAND MUST DROP NET ZERO 2050

Climate Change Realism Not Alarm

Climate change alarmism has become a quasi-religion, where many normally rational scientists have moved to a rigid belief state rather than continuing to question the science and constantly check the latest evidence. Fortunately, a core of respected atmospheric physicists continues to speak out and keep rational debate alive [e.g. 1, 2, 3]. Environmental activist and writer, Michael Shellenberger [4], also counsels strongly against climate doom thinking.

Apart from the many journals publishing climate science, groups such as the CO2 Coalition [5] draw on publications from both sides of the science divide and report on latest evidence to maintain some reality in what is too often a highly politicised debate that is well removed from fact. The Earth is in a gradual warming cycle, and would be with or without any anthropogenic effect, but there is mounting evidence that we are not facing anthropogenic climate catastrophe. We do, of course need to take some adaptive measures to better respond to an ever-changing climate.

In a very recent post, Pielke [6] has analysed new scenarios from the Coupled Model Intercomparison Project (CMIP) that will underpin the next IPCC report AR7 - the seventh assessment report due in 2029. The new framework has eliminated the most extreme emissions scenarios that have dominated climate research over much of the past several decades - specifically, RCP8.5, SSP5-8.5, and SSP3-7.0. RCP8.5, in particular, was infeasibly pessimistic in its 2100 best estimate global warming projection of 4.3°C but has been the foundation for much government policy and thousands (actually the majority) of academic research papers, which have presumed the worst possible outcome from the outset of the research.

The new CMIP7-MEDIUM scenario, which by 2100 projects 2.5°C warming above 1850-1900 pre-industrial levels, is broadly similar to the current medium SSP4.5 scenario (4.5 W/m2 anthropogenic radiative energy input to the atmosphere - cf ~3 W/m2 today). However, Pielke notes that even CMIP7-MEDIUM is pessimistic, and such scenarios still rely on strong water-vapour-enhanced temperature raising effects from additional CO2 that have been refuted by physicists such as Lindzen & Happer [1], and Coe et al. [7].

It is increasingly clear that the extraordinary Net Zero project is no longer based on compelling, strong scientific evidence, and it is time to retreat from extremism.

Note also that aggressive climate change policy has been overshadowed recently in developed countries by the need to ensure security of energy supply at a reasonable price, and it is clear that pursuing a renewables policy involving a high percentage of solar and wind power generation has led to cripplingly high consumer electricity prices [8] and de-industrialisation. As a powerful example, Australia continues to wrestle with this problem and its politics, especially in South Australia [9].

In this context, at what cost Net Zero 2050?

Net Zero 2050 – Unnecessary and Impossibly Costly

The NZ Coalition government has apparently relaxed its aim to meet commitments under the 2015 Paris Climate Agreement but so far has not dropped Net Zero Carbon 2050. And this despite NZ’s currently reported total greenhouse gas (GHG) emissions being ~0.15% of the global GHG emissions. It is prudent to manage CO2 resulting from human activities, but extreme Net Zero emissions policies are not justified in planning our energy future [8,10], especially when we are trying to rebuild the economy maintain our primary industries, and invest in infrastructure, and the energy, health, and education systems.

Nothing NZ does to reduce GHG emissions can possibly have any measurable effect on global temperatures. This alone makes Net Zero 2050 unnecessary for this country but there is also the crippling cost to the economy. The analyses of Kelly [11,12] demonstrate the massive cost (over $550 Bn for NZ) and the financial impracticality of achieving Net Zero. Whether on a cost or global emissions basis, it would be economic folly for our government to persist with a Net Zero 2050 goal.

The Engineering Capability Deficit

Let’s say for a moment that the Government continues to chase Net Zero 2050. We quickly see a political decision taken without considering the technical feasibility of reaching the goal. This would require deep, economy wide systems changes, concentrated in engineering heavy sectors, and absolutely dependent on a huge increase in the professional and trades engineering workforce:

• Energy system transformation: Electricity generation – The NZ Infrastructure Commission estimates that generation capacity must increase by ~170%. This requires a major buildout of generation capacity (renewable and other), on top of an already 85% renewable electricity system.

• Upgrades to the grid - transmission and distribution networks

• Development of energy storage (hydro and other)

• Transport electrification and modal shift - EV charging networks, rail electrification, port upgrades, and urban redesign.

• Industrial decarbonisation: Green hydrogen, process heat fuel switching, and industrial plant retrofits.

• Buildings: New low carbon construction and retrofits for heating electrification and energy efficiency upgrades across the entire built environment.

• Materials demand: Delivering net zero would require about 10% of global annual production of lithium, cobalt, neodymium, and other critical materials — implying significant engineering effort in supply chain and materials management as well.

• Water, waste, transport, housing, and climate resilient infrastructure upgrades

Infrastructure delivery and wider engineering-intensive projects already face severe workforce shortages. Engineering New Zealand (EngNZ) reports that the country already needs 1,500–2,300 additional engineers every year just to meet baseline demand. This does not include a massive increase in engineering capacity needed to meet infrastructure and climate targets implicit in the Net Zero 2050 project

The International Energy Agency (IEA) and McKinsey both show that:

• Net Zero pathways require roughly double historic infrastructure delivery rates.

• Engineering, design, and project delivery roles are the critical bottleneck.

NZ’s current professional engineering workforce based on EngNZ membership is around 22,000 – 23,000. This does not include many engineers in industry who are not EngNZ members, or who are doing professional work with a technician qualification.

AI assistants suggest that to meet the workload requirements 2025-2050 New Zealand would need a sustained workforce of 50,000 to 75,000 professional engineers.

This equates to about 1.2 - 1.9 million person-years of required professional engineering time - roughly two to three times more professional engineers continuously than in the present workforce on a median scenario. This looks like a shortfall of not less than 40,000 engineers, and at least one million person-years work over 25 years, to execute a Net Zero 2050 agenda. A higher estimate would be a shortfall of at least 50,000 engineers.

There is no possibility of our university engineering schools addressing this shortfall. Even if they had the capacity, the intake of school leavers with the necessary maths and physics simply does not exist.

Similar massive capacity constraints would doubtless apply to tradesmen working in various manufacturing and service capacities needed for a Net Zero commitment.

The Opportunity Cost

If pursuing a net Zero economy for NZ by 2050 is not only unnecessary but is also impossible due to binding constraints on finance, labour, and materials, then continuing to invest heavily in that goal imposes large and damaging opportunity costs. Not disputing climate change itself, we must focus on economic realism, scarce resource allocation, and social welfare trade offs.

Financial Opportunity Costs

Capital directed into Net Zero projects that cannot deliver the 2050 target represents foregone investment in areas with higher returns and lower risk. Many climate motivated projects rely on long payback periods justified primarily by policy assumptions. If Net Zero 2050 is infeasible, many such projects will underperform or completely fail to deliver.

The lost opportunity is not only the capital itself but compounding returns that could have been generated elsewhere. NZ has high international debt and must increase the speed and productivity of its economy. Funds absorbed by marginal emissions abatement projects are unavailable for essential transport and energy infrastructure new-build or renewal, productivity enhancing investment, social assets such as health and education, or even future climate adaptation measures (if and when they become essential to undertake). Both government and private balance sheets are constrained. Misallocation today reduces fiscal flexibility and raises future borrowing costs, leaving the economy weaker and less able to fund future adaptation.

Labour and Skills Opportunity Costs

With a chronic shortage of technical specialists and tradespeople, prioritising Net Zero projects diverts skilled workers onto incremental emissions reduction efforts, compliance tasks, and retrofit projects with limited system wide benefit. These same workers are urgently needed for infrastructure resilience, natural hazard adaptation, maintenance backlogs, and productivity enhancing innovation. Training pipelines take decades, so misallocation means that essential projects are delayed, infrastructure deteriorates further, and skilled workers may leave NZ to find more meaningful work.

Material Opportunity Costs

Net Zero pathways require large quantities of steel, concrete, copper, aluminium, rare earth elements, and specialised equipment, all subject to global scarcity and geopolitical competition. If New Zealand cannot secure enough materials to achieve Net Zero, then these projects waste scarce physical resources. Materials tied up in low impact decarbonisation efforts are unavailable for seismic strengthening, water infrastructure renewal, transport upgrades, and disaster recovery capacity. For a small import dependent economy, such misallocation raises costs across all sectors and increases vulnerability to supply shocks.

Infrastructure Trade offs

Continued pursuit of an unattainable Net Zero goal can undermine the energy system reliability. Investments such as in a high percentage of solar and wind power may prioritise theoretical emissions reductions over firm energy capacity and grid redundancy, or urgent maintenance and development of transport networks. The result is higher outage risk, infrastructure failures, and reduced economic resilience. These costs directly affect social welfare.

Adaptation Opportunity Costs

Adaptation must be NZ’s central priority. A continued focus on mitigation will crowd out investment in flood protection, coastal defence, water security, urban heat resilience, and health system preparedness. Every dollar not spent on adaptation increases future disaster costs and social disruption.

Political and Institutional Opportunity Costs

Persisting with an unnecessary and unattainable climate change mitigation target consumes political capital, erodes public trust, and undermines policy credibility. Once institutions lose legitimacy, even well designed policies struggle to gain support.

Conclusion

The opportunity cost of continuing to pursue Net Zero 2050 lies not in environmental harm but in economic, social, and institutional damage. It is vital that Government and its advisors have a sufficient understanding of the latest objective science to assess the real risks from climate change and their limitations, and not be steered by alarmist rhetoric.

Government has a critical need to be laser focused on economic recovery and regeneration, and to invest in enabling infrastructure, education and health services. We cannot afford to divert scarce resources away from resilience, productivity, and appropriate climate change adaptation - investments that will determine New Zealand’s wellbeing in the climate future it will actually face.

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John Raine is an Emeritus Professor of Mechanical Engineering, and a former researcher in alternative and renewable energy systems. He formerly worked in the UK engine and vehicle test plant industry and has had a long involvement with New Zealand’s research and innovation system.

Michael Kelly is Emeritus Prince Philip Professor of Technology in the University of Cambridge UK, Chairman of the Renewable Energy Foundation (UK) and a Trustee of the Global Warming Policy Foundation (UK)

Bryan Leyland is a semi-retired Electrical and Mechanical consulting engineer specialising in power systems. He has experience in almost every form of generation from nuclear power to wave power.

References

1. Richard Lindzen and William Happer, “Physics Demonstrates that Increasing Greenhouse Gases Cannot Cause Dangerous Warming, Extreme Weather or any Harm”, CO2 Coalition, 7th June 2025. https://co2coalition.org/wp-content/uploads/2025/06/Lindzen-Happer-GHGs-and-Fossil-Fuels-Climate-Physics-2025-06-07.pdf

2. John Christy, Judith Curry, Steven Koonin, Ross McKitrick, Roy Spencer, “A Critical Review of Impacts of Greenhouse Gas Emissions on the U.S. Climate”, Report of the Climate Working Group to U.S. Energy Secretary Christopher Wright, USA Department of Energy, 23rd July, 2025.

3. William Happer, Steven E. Koonin, Richard S. Lindzen, Tutorial Submission on Global Warming and Climate Change to United States District Court Northern District of California San Francisco Division, Case No. C 17-06011 WHA, Case No. C 17-06012 WHA. Hearing Date: 21st March, 2018.

4. Michael Shellenberger [11], “Apocalypse Never”. Harper Collins, ISBN 9780063074767 international edition; ISBN 9780063001701 e-book.

5. CO2 Coalition https://co2coalition.org/

6. Roger Pielke Jr, “RCP8.5 is Officially Dead” The Honest Broker, Substack, 29th April 2026. https://substack.com/home/post/p-195733015

7. David Coe, Walter Fabinski, Gerhard Wiegleb, “The Impact of CO2, H2O and Other “Greenhouse Gases” on Equilibrium Earth Temperatures.” International Journal of Atmospheric and Oceanic Sciences. Vol. 5, No. 2, 2021, pp. 29-40. doi: 10.11648/j.ijaos.20210502.12, 23rd August, 2021

8. John Raine and Bryan Leyland, “A Realistic Energy Future”, Bassett Brash and Hide, 24th August 2025 https://www.bassettbrashandhide.com/post/john-raine-and-bryan-leyland-a-realistic-energy-future

9. Chris Uhlmann, “Chris Bowen says no one wants more fossil fuels. The rest of the world begs to differ.” The Australian, 2nd May 2026 https://www.theaustralian.com.au/inquirer/chris-bowen-says-no-one-wants-more-fossil-fuels-the-rest-of-the-world-begs-to-differ/news-story/d68e4ffd9e12a57bf11998e75584bb59

10. John Raine, Michael Kelly, Bryan Leyland, David Lillis, “A response to Dame Anne Salmond on Climate Change.” Bassett Brash and Hide 27th September 2025 https://www.bassettbrashandhide.com/post/john-raine-michael-kelly-bryan-leyland-and-david-lillis-a-response-to-dame-anne-salmond-on-climate

11. Michael Kelly, “Achieving Net Zero: A report from a putative delivery agency”. Note 30 The Global Warming Policy Foundation © Copyright 2022, The Global Warming Policy Foundation, UK.

12. Michael Kelly, “An Assessment of the NZ Resources Needed for Carbon Zero”, a presentation to Engineering New Zealand, 1st December 2020, Auckland.