NZCPPR | 17 Nov 2022

If the Covid pandemic taught us anything, it’s to be very cautious about the influence of modelling on government policy. Prime Minister Jacinda Ardern used exaggerated predictions of potential deaths to justify the world’s harshest lockdowns.

The inevitable conclusion is that the underlying assumptions behind all modelling should be challenged – especially when they are being used by politicians to justify extremist policy changes. And just as it was with Covid, so too it is with climate change. 

It turns out that some of the assumptions underpinning United Nations’ emissions scenarios are so implausible that they have now been discredited and abandoned. Yet Jacinda Ardern’s Government is continuing to use them to develop public policy. The fair suspicion is that they are doing this deliberately to manufacture a ‘crisis’ that requires radical intervention and state control to restrict freedom and rights through massive new taxes, regulations, and spending.

To better understand how this is happening, we need to familiarise ourselves with a key feature in New Zealand’s climate modelling: ‘radiative forcing’ – a measure of how much energy comes from the sun, compared to how much is radiated back into space. In simple terms, if more energy arrives than leaves, the atmosphere will warm, but if more energy leaves than arrives, it will cool.

Radiative forcing was adopted by the UN’s Inter-Governmental Panel on Climate Change (IPCC) in their 2014 fifth assessment report to describe four trajectories of human induced greenhouse gas concentrations. Called Representative Concentration Pathways or RCPs, the four measures are RCP2.6, RCP4.5, RCP6, and RCP8.5 representing radiative forcing of 2.6, 4.5, 6, and 8.5 watts per square metre.

The IPCC describes RCP2.6 as the “stringent mitigation scenario” that aims to keep “likely” global warming below 2°C above pre-industrial temperatures. Under this scenario, by 2100, the likely increases in global temperature would range between 0.3 and 1.7 degrees, and the likely sea level rise between 0.26 to 0.55 metres.

RCP4.5 and RCP6.0 are described as “intermediate scenarios”, with a likely increase in temperature from 1.1 to 3.1 degrees, and a sea level rise of 0.32 to 0.63 metres.

The fourth measure, RCP8.5, is described as a scenario “with very high greenhouse gas emissions”. By 2100, temperatures are likely to range from 2.6 to 4.8 degrees, with a sea level rise of 0.45 to 0.82 metres.

New Zealand’s National Institute of Water and Atmospheric Research, NIWA, our key climate research agency, embraced RCP8.5 for its modelling work, describing this pathway ‘with very high greenhouse gas emissions’ as “business as usual”. It is used extensively in all government climate reports as a likely outcome.

So, what are the assumptions that underpin NIWA’s “business as usual” model?

The RCP8.5 scenario and its SSP5-8.5 successor assumes the world is going to massively increase emissions of greenhouse gases by intensifying its future consumption of coal by 500 percent.

It is actually an impossible scenario. To achieve it would mean that coal would have to be used to generate all of the world’s energy – replacing natural gas, nuclear, and renewable generation, as well as replacing all fuels in the world’s transportation fleet.

To do this would take more than all known reserves of coal.

In reality, NIWA’s “business as usual” scenario is actually an improbable “climate Armageddon” scenario. And it is this that our government officials and politicians are using to justify the “climate emergency” and the suite of draconian policies that are being implemented to address it.

RCP8.5 underpins a vast range of government reports including New Zealand’s first Emissions Reduction Plan, its first National Climate Risk Assessment, its first National Adaptation Plan, its coastal hazards and climate change Guidance for Local Government, its interim guidance on the use of new sea-level rise projections, along with all associated regulations and legislation.

While questions over the validity of this scenario have been swirling around for years, an important new development occurred on the eve of COP27 (the annual climate change talk-fest that is now underway in Egypt, where 35,000 delegates have flown in from all over the world to discuss how to reduce human carbon emissions) that changes everything.

This week’s NZCPR Guest Commentator, Barry Brill, the Chairman of the New Zealand Climate Science Coalition and a former National Party Minister, explains the significance of what has happened in the first of a series of four articles:

“On the basis of recent science, the UN has halved to only 2.5°C its prediction of global temperatures by the year 2100… The collapse of long-standing global warming expectations is largely the result of the UN’s belated rejection of the most extreme scenario of future emission levels – known as RCP8.5. This unrealistic input to climate models has for many years applied a massive upward distortion to the calculation of likely future temperatures.

“The UNFCCC has now banished RCP8.5 (and its successor SSP5-8.5) from all its policy-making at COP27. For good measure, it has also dropped the RCP6.0 scenario, and is now focusing on an envelope between 2.6 and 4.5 – a new addition, RCP3.4.”

Barry believes the abandonment of the extreme RCP8.5 scenario is the most important climate change story of the decade – especially for New Zealand, since it means that all of the runaway global warming scenarios that underpin our climate policy framework, will need to be replaced with measures that are more realistic.

The implications are huge, since all reports produced by the Climate Commission, NIWA, the Ministry for the Environment, the Department of Internal Affairs, and many other agencies, are based on the now obsolete PCR8.5 and SSP5-8.5 scenarios and will need to be redone.

For example, the key National Climate Change Risk Assessment report, states, “this NCCRA used projections based on RCP8.5, a high greenhouse gas emissions scenario.”

It then goes on to explain the disastrous consequences of their comically implausible predictions: “Temperatures predicted under RCP8.5 will likely cause the loss of 200–300 indigenous plant species; increase risks of invasion by introduced species; increase introduced vertebrate predators such as ship rats, and predation on subalpine birds, lizards and invertebrates by stoats, mice and hedgehogs.

“New Zealand’s low-lying coastal areas are exposed to ongoing sea-level rise and associated rising groundwater and salinisation, and extreme events. About 675,500 people live in areas currently prone to flooding. A further 72,065 people live in areas that are subject to 1 percent probability of extreme sea-level elevation. Inland communities are exposed to extreme events and gradual changes, which may alter the viability of crucial economic enterprises.

“Sea levels are projected to rise by up to 0.90 m by 2100 under RCP8.5 for all zones. Extreme storm tides, winds and rainfall are projected to increase in frequency and magnitude in all regions for 2050 and 2100 under RCP8.5. The intensity of tropical cyclones is also projected to increase. This will result in flooding, landslides and erosion that can have immediate and long-term implications, due to damage to households, displacement and trauma.

“Some of the most pressing needs in New Zealand relate to the impacts of sea-level rise, which includes rising groundwater and salinisation, erosion and more damaging storm surges. One metre of sea-level rise from the present day, which may be experienced by 2100 under RCP8.5 H+, will expose more than 49,000 buildings to a 100-year, extreme sealevel flood. These buildings have a replacement value of about $12.4 billion. Where managed retreat is the only option, significant investment will be required to support these communities.”

Our Prime Minister, not content, it seems, with using her Armageddon forecasts to drive more than one in five farmers off their land, is now planning to use exaggerated climate predictions to “evacuate” Kiwis from the areas presumed to be at risk of flooding, by relocating them to higher ground in what is described as “managed retreat”.

This concept is set out in New Zealand’s first National Adaption Plan. Published just three months ago, it uses the discredited SSP5-8.5 and RCP8.5 measures to justify widespread government intervention: “Under the highest emission scenario, sea-level rise in Aotearoa is projected to increase by 1.09 metres on average. We must adapt to both rising sea levels that threaten coastal ecosystems and infrastructure, and increased frequency and magnitude of extreme events – such as coastal inundation and flooding that can damage homes, roads and other infrastructure, and affect access to coastal areas.”

To progress this extremist central planning exercise, the Associate Minister of Local Government Kieran McAnulty has released a new report based on RCP8.5, that identifies 44 ‘vulnerable’ communities around the country deemed to be at risk of flood hazards.

In a Radio NZ interview Minister McAnulty explained, “We know that New Zealand is prone to weather events and we also know with climate change that those weather events are becoming more severe and more frequent. This report painted a pretty grim picture but it is also the reality and it’s important information for any planning going forward.”

He said a “massive conversation” is needed as the Government considers the options – including the “total abandonment” of areas of high flooding risk, along with “managed retreats” – and he noted that the costs of forcibly removing people from their land should be shared between homeowners, local and central government, insurance companies and banks.

The Minister also explained that some requirements needed for removals have been included in the new Resource Management Act, with the balance expected in a Climate Adaptation Bill next year.

The Department of Internal Affairs included Kaitaia in the Far North, along with the kumera-growing area of Ruawai in the Kaipara District, in their register of at-risk communities earmarked for possible managed retreat or abandonment. However, locals were not convinced.

Northland Regional Council councillor Joe Carr, who is also the chair of the Awanui River Flood Management Advisory Committee, said that millions of dollars had already been spent on flood protection work for Kaitaia. As a result, while July’s massive “one-in-500-year rains” closed State Highway One, the town remained unscathed. And he reiterated that while more could be done – such as constructing an upstream detention dam on the river – it was “not necessary to abandon the town in the face of flooding challenge”.

Similarly, Ruawai’s Raupo Drainage Committee chairman Ian Beattie said, “abandoning 8,000 hectares of flats protected by a network of stopbanks, floodgates and drainage channels was not necessary.” He believes any suggestion of the community “having to move”  was a case of “politics rather than science driving the debate”.

The new Mayor of Kaipara Craig Jepson also took issue with the Minister’s report, saying that a sea level rise of around 2.2 mm annually – or about 24 centimetres over the next 100 years – was nothing to get worried about.

Underpinning the Minister’s report is new guidance published by the Ministry for the Environment in August that states, “The upper-range scenario SSP5-8.5 and its upper likely range of 8.5 H+ should continue to be used”. As a result, it predicts an Armageddon sea level rise of 1.09 metres by 2100.

And that demonstrates the problem. A completely fictitious climate scenario is being used by politicians and officials to create alarmist predictions to scare the public and justify government intervention on an unprecedented scale.

Since the UN’s new global warming prediction of 2.5°C from 1850 to 2100 is only a shade higher than the 2.0°C target by 2050 in the Paris Agreement, in his third article Barry Brill asks, “Does it still make sense for the world to spend trillions of scarce dollars in trying to mitigate that last 0.5°C of possible warming in 2100?”  

The answer, of course, is no. This madness must stop, and that starts by challenging our politicians to explain why they and their legions of report writers are using extremist RCP8.5 modelling scenarios as the basis of public policy in New Zealand.  

All climate change policy based on RCP8.5 should be suspended immediately while the modelling is redone using scenarios with assumptions based on reality, not fantasy.

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