Rising tide of interest in sea level rise

Australian Antarctic Division: The approaching centenary of Douglas Mawson's Australasian Antarctic Expedition (1911-1914) will be celebrated in part for its contributions to science, particularly in the fields of geology and meteorology. A perhaps lesser-known scientific contribution, but a significant one given the challenges that face us today, was the establishment of tide gauges at Cape Denison and Macquarie Island in 1912.

Thanks to measurements from these gauges, modern-day scientists have a benchmark for sea level 100 years ago. This has allowed them to detect a rise in sea level, as a result of climate change, of 2.0 ±1.3mm/year at Cape Denison and 2.0 ±0.8 mm/year at Macquarie Island (approximately 200 mm over 100 years).

According to Australian Antarctic Division Mapping Officer, Henk Brolsma, just as important as the installation of these gauges was the proper documentation of the measurements in a scientific publication.

'The notes on the Cape Denison tide gauge were prepared by Captain Robert Bage, with Doodson, in 1939, documenting important datum information which is critical for sea level studies today; and the original graph paper showing the tidal records was archived at the Mitchell Library in NSW,' Mr Brolsma says.

'It's an important message for all scientists. You never know what your data will be used for, so it's important to document it correctly. Mawson's team weren't necessarily looking at sea level change when they made these measurements, but 100 years on, the tidal data has played a critical role in detecting sea level rise as a result of climate change.'…

The tide gauge installed at Cape Denison in 1912 and operated by Captain Robert Bage, photo by Australian Antarctic Division, © Commonwealth of Australia