Planning for Meteors.

Time to Readjust

A catastrophic meteor strike in Auckland is not impossible. Scientists acknowledge that large meteor impacts have occurred in Earth’s history and could occur again. The consequences would be devastating beyond imagination. Yet no sensible council would hire additional expert staff, pay consultants excessive rates, commission expensive reports, impose planning restrictions, redesign infrastructure networks or burden ratepayers with large ongoing costs based on the possibility of a meteor strike. Why? Because prudent governance requires a balance between consequence, probability and cost.

The same principle should apply to climate scenarios.

Regional councils are expected to plan prudently for the future. They must consider floods, storms, droughts, coastal erosion and infrastructure resilience over many decades. Few would dispute that climate change should be part of that planning. The real question is not whether councils should prepare for risk, but how far they should go in basing present-day costs and restrictions on scenarios that may now sit outside the bounds of reasonable probability.

For many years the climate scenario known as RCP8.5, now defined as SSP5 – 8,5 became widely used in government and local authority planning. Originally developed as a high-end emissions pathway, it increasingly came to be treated in some planning exercises almost as a “business as usual” future.

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Recently the IPCC had a high-level committee investigate the use of RCP8.5. Their measured response was that it was no longer “plausible”. Read – “as near as impossible as the meteor’s arrival”.

The assumptions embedded in the RCP8.5 scenario were always at the absurd end of reality. For example, it presumed a world population of 14 billion when, even, the UN says 10 billion could be an overstatement. It assumed coal use to go up by a factor of 8 to 9 times. That was never going to happen when usage was already diminishing. It assumed almost nil technological development in a world that was bursting daily with new inventions, new sophisticated techniques in every field.

Even allowing for stress testing options to be outliers the assumptions behind RCP8.5 were just too extreme to be taken seriously in any planning scenarios. It was meteors hitting Auckland stuff.

Why then is our government in various departmental divisions – MfE, NIWA and others and regional and district councils still including RCP8.5 in a myriad of expensive planning documents, reports, restrictions, options? Why are ratepayers faced with planning decisions based on RCP8.5 that could cost many hundreds of millions of dollars.‍ ‍

Take sea level rise. Using the absurdly high option meant sea level rise was determined by some regional councils to be 1.5 metres inside 100 years.

Each year the sea level would need to rise 15mm instead of the 1.45mm currently. It is easy to determine whether the model is realistic or not by taking the last 5 years actual sea level data (approx. 7.25mm) and matching it with the model that says it should have risen 75mm. So, the models are running 10 times faster than reality.

Auckland Council, for example, has spent many millions of dollars over the past five years on climate hazard assessments, shoreline adaptation planning, coastal modelling, consultation and resilience planning that utilise climate scenarios including RCP8.5. While the specific cost of retaining RCP8.5 is not publicly identified, the total planning and assessment programme may reasonably be estimated in the tens of millions of dollars, with the much larger issue being the potential influence of high-end scenarios on future infrastructure and land-use decisions worth hundreds of millions or even billions of dollars.

If RCP8.5 continues as a plausible scenario in the Council’s planning ratepayers are beginning to now and certainly will face huge, unnecessary cost. When extreme scenarios are embedded into planning rules, they can trigger very real economic consequences today. Coastal hazard overlays expand. Development restrictions tighten. Floor levels and engineering requirements increase. Infrastructure is upgraded or relocated earlier than necessary. Land values are affected and borrowing costs rise. These are not theoretical outcomes; they are immediate financial burdens carried by communities, businesses and households.

Good governance is not about preparing for every imaginable catastrophe regardless of likelihood. It is about making proportionate decisions based on credible evidence, realistic probabilities and responsible stewardship of public money.

For that reason, continued use of RCP8.5 as part of a central planning framework for Government and regional councils is not justified or necessary. The evidence now suggests that further large-scale expenditure and regulation based primarily on that scenario is unwarranted and should stop.