There has been NO significant sea level rise in the harbour for the past 120 years, and what little there has been is about the height of a matchbox over a century.  Along the northern beaches of Sydney, at Collaroy there has been no suggestion of any sea level rise there for the past 140 years. Casual observations from Bondi Beach 1875 to the present also suggest the same benign situation.  A rush to judgement by local councils and State Governments by legislating harsh laws and building covenants along our coastlines now seems misplaced. The falsehoods and mendacity of the IPCC and climate alarmists should be rejected out of hand, and efforts be made to ensure that science, not propaganda, defines our school curricula in matters of climate and sea levels.

Rock Island, or Pinchgut, or Fort Denison, in 1885.

The Tide-gauge sea-level arrangements in Sydney Harbour Our story of sea levels in Sydney Harbour, like the temperature story, also begins at the time of the First Fleet in 1778, when Captain Arthur Phillip turned his attention to building his new colony. From Sydney Cove he had a reasonable view of an island of rock sitting in the blue harbour waters a short distance away, and which was destined to become the site of tidal gauges in the harbour.

This island, about 1 km northeast of Sydney Cove, and only a few hundred square metres in area, was named “Rock Island” by Phillip. Not only did Captain Phillip have competent recorders of temperature with him in the First Fleet—he also had stonemasons and plenty of penal labour, and so he set to work quarrying the top from Rock Island in order to supply the new colony with building stone.
Although much smaller than the infamous Alcatraz, Philip also used the island for punishing convicts for perceived wrongdoings, and the meagre rations associated with this punishment gave rise to the alternative name ‘Pinchgut”. With the island (Figure 1) now flattened, it became a splendid foundation for some fort building. The Fort was designed in 1839, and was built between 1841 and 1857, (You et al., 2009) characterised by the rounded Martello Tower design popular in European fort-making in the 19th Century.
As an aside, this style of architecture should not be confused with an Australian thoroughbred racehorse also called ‘Martello Towers’, a champion who famously won four Class 1 events in 1959, including the ABC Derby at Randwick in Sydney. His grand dam was named ‘Fort Denison’, so in 1956 the owners of this young foal quite logically named the grey champion ‘Martello Towers”.