There are two reasons why NSW’s decision to remove the compulsory application of coastal councils’ benchmarks for rises in sea levels, as outlined by Special Minister of State Chris Hartcher, is an important development in the debate on global warming. First, it represents a retreat from former official certainties and, of more tangible significance, it boosts the likelihood of Victoria and Queensland following suit.
The benchmarks, set by the previous NSW Labor government, included a projected 90cm sea level increase by 2100 — much higher even than the IPCC’s projection of 59cm. It was also considerably above the observed trend, which implies a far more modest rise of around 20-25cm by century’s end.
Hartcher noted that NSW Chief Scientist and Engineer Mary O’Kane “has identified uncertainty in the projected rate of future sea level rise, given that the scientific knowledge in the field was continually evolving”. As far as I am aware, the previous government made no reference to the chief scientist harbouring any such “uncertainty”. O’Kane’s advice to Hartcher includes the following statement:
“In considering the science behind sea level rise benchmarks, the one constant that emerges is change. The way the science has been used to determine benchmarks is adequate, given the current level of knowledge. However, for some years to come there will be more and better models for predicting sea-level rise which will be informed by more and better data enabled by rapid advances in sensing, positioning, computational and imaging technologies.”
This statement and what follows in the 32-page document, clearly imply there is much more research to be undertaken on assessing likely sea-level changes. This runs counter to oft-heard warmist assertions of a fabled “consensus” that leaves no room for doubt or dissent. Worth noting is that several ardent warmists provided O’Kane with their views as she formulated her own. One assumes their voices were not heeded quite so much as before.
Indeed, the assessment includes a recommendation that “work should begin on establishing the appropriate framework for deriving updated sea level projections for NSW coastal locations and then refining these projections as yet further model outputs become available”. One might be excused for asking how the previous projections were made if there was no “appropriate framework”! One potential problem with having scientists establish such frameworks is their tendency to emphasise the need to develop better models. If those models are based on the ones used by the IPCC they will include incorrect assumptions about future warming.
Also interesting – indeed, it is a genuine riddle — is the assessment’s comment that regional variations from the global average should be somewhere in the range of plus or minus 0.15 of a metre. However no explanation is given as to why the previous NSW projection for 2100 (90cm) differed by so much more than 0.15m from the IPCC global average projection of 59cm. Put it down as another of climate science’s not-quite-settled mysteries.
Des Moore, a former Deputy Secretary of Treasury, is Director of the Institute for Private Enterprise