Fort Denison is a heritage fort on a Sydney Harbour island, once called Pinchgut. This former military site is the most complete Martello Tower in the world and a popular Sydney attraction. Fort Denison was in the news recently on the topic of sea level rise. Watch the video below courtesy of Sky News Australia. In the opinion of experienced Hydrographic Surveyor Daniel Fitzhenry, who features in the Sky News interview, mean sea level as measured at Fort Denison has not increased over the period 1914-2019. Further down I present a chart that I have created from the raw Bureau of Meteorology Tide Gauge data. There is a clear trend of increasing sea level relative to the datum from around 1930 to present day. Roughly an increase of 10 centimetres, less than half of what is often claimed by the climate alarmists – e.g. the CSIRO. Note: the chart is interactive when viewed on a larger device e.g. desktop PC. Share your thoughts in the comments below or join the conversation on Twitter.