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Sydney Sea levels rising at just 6.5cm per century. Peak-panic is behind us.

In The Australian Bob Carter compares the long term tide gauge record in Sydney with projections, and exposes the exorbitant cost of insurance for alarmist sea level forecasts. The good news is that it appears councils are waking up, and  “peak-sea-level-panic” is behind us.

Sea-level alarmism has passed high tide and is at last declining. With luck, empirical sanity will soon prevail over modelling.

After years of research it turns out that talking about “global”  sea level rise is nearly meaningless to real people who live in one place. The ocean rise varies locally from beach to beach from as little as 5cm per century to as much as 16cm per century. The variations are mostly due to different rates of land subsiding or rising.

More importantly, the rate of rise was either the same or was even faster before World War II when CO2 levels were “safe”.

Figure 5: Comparison of decadal rates of change over historical record. Analysis based on relative 20-y moving average water level time series. | Watson 2011

Fort Denison in Sydney has one of the longest running continuous records, starting in 1886, and finally local councils are realizing that they need to use the local data to plan ahead, not the IPCC’s one-size global fear index.

For example, measurements at Sydney between 2005 and 2014 show the tide gauge site is sinking at a rate of 0.49mm/yr, leaving just 0.16mm/yr of the overall relative rise as representing global sea-level change. Indeed, the rate of rise at Fort Denison, and globally, has been decreasing for the past 50 years.

Let’s cheer, Shoalhaven Shire Council shifted the sea-level-panic-index back a notch, rejecting the worst case IPCC scenario, settling for a slightly less scary one, and importantly, used the local Fort Denison record and ruled out “satellite or model-generated sea-level estimates until their accuracy is guaranteed”.

When councils plan for scenarios that never happen, the pointless insurance can cost some unlucky home owners tens of thousands — in one shire – $40,000 each.

Figures from RP Data property information specialists show that between 2011 and 2014, Eurobodalla property values suffered a 5.3 per cent loss in value compared with increases of 4.9 per cent and 7.3 per cent for neighbouring coastal shires that didn’t have equivalent restrictive sea-level policies. In the worst cases, individual properties have lost up to 52 per cent of their market value

In three years, individual Eurobodalla properties lost about $40,000 in value. With 22,000 properties in the shire, this represents a capital loss of $880m at a rate of $293m a year. This steady loss of rateable value means householders will face higher rate increases.

If you own a home near the sea, you might want to send this sort of  information to your councilors:

Queensland Deputy Premier Jeff Seeney recently notified Moreton Bay Regional Council of his intention to direct it to amend its draft planning scheme “to remove any assumption about a theoretical projected sea level rise due to climate change from all and any provisions of the scheme”. Seeney said his intention was to use a statewide coastal mapping scheme “that will remove the ‘one size fits all’ approach that incorporates a mandatory 0.8m addition to historical data”.

At last, a responsible government has recognised that global average sea-level change is no more relevant to coastal management than average global temperatures are to the design of residential heating and cooling systems — local weather and local sea-level change is what matters.




P. J. Watson (2011) Is There Evidence Yet of Acceleration in Mean Sea Level Rise around Mainland Australia?. Journal of Coastal Research: Volume 27, Issue 2: pp. 368 – 377.  doi: 10.2112/JCOASTRES-D-10-00141.1 [Link Abstract PDF ]

White, Neil J., Haigh, Ivan D., Church, John A., Koen, Terry, Watson, Christopher S., Pritchard, Tim R., Watson, Phil J., Burgette, Reed J., McInnes, Kathleen L., You, Zai-Jin, Zhang, Xuebin, Tregoning, Paul: (2014) Australian Sea Levels – Trends, Regional Variability and Influencing Factors, Earth Science Reviews, doi: 10.1016/j.earscirev.2014.05.011

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