Pictures of Australian landmark misused to deny sea-level rise

Two images taken almost a century apart at Fort Denison in Sydney, Australia are being held up on social media as evidence that sea levels are not increasing -- contrary to what available science has demonstrated. But scientists told AFP that the claims omit the effect of tides, and that data undeniably shows seas are rising on a local scale and more prominently worldwide because of human emissions.

"Massive sea level rises have been sold to us, and taught to our children," says a June 8, 2025 post shared thousands of times on Facebook.

The post juxtaposes two photos of Fort Denison in Sydney, Australia that, while claimed to have been captured 93 years apart, show the water seemingly reaching the same height along the structure.

Text over the images says: "Unprecedented sea level rise."

The same comparison also surfaced elsewhere on Facebook, as well as on LinkedIn and X.

Reverse image and keyword searches revealed that the two photos were indeed taken almost a century apart: the first appears on the Flickr account of Australia's Powerhouse Museum with a caption indicating it was "taken circa 1934," while the second was published in a 2023 article on a tourism blog (archived here and here).

But they do not disprove that sea levels are rising at both global and regional levels.

Fort Denison level increase

The National Oceanic and Atmospheric Administration (NOAA) has been monitoring the relative sea level -- the height of the water relative to the land -- at Fort Denison since 1886 (archived here).

Data through 2022 shows such levels have risen by about 0.03 inches (0.8 millimeters) per year on average, or a change of slightly above three inches (eight centimeters) over 100 years, according to the US agency.

A spokesperson for Australia's Bureau of Meteorology similarly told AFP that between 1914 and April 2025, the local annual mean sea level has increased.

"Just like other weather and ocean variables, some years have higher than average sea level while other years have lower than average sea levels," the spokesperson said June 16.

Multiple studies have also observed changes in Australia's sea levels over time (archived here and here).

"The reality is that the average global sea level is rising, and the sea level around Fort Denison is no exception," climate scientist Shaina Sadai told AFP June 13 (archived here).

"A photo is just a single snapshot in time and cannot give us a complete picture of long-term changes," she said. "Many factors can influence water levels at a single moment, such as the day-to-day tidal cycle."

Because of its scale, Fort Denison's sea-level rise would not be discernible from a far-away aerial view of the site.

A 2012 report shows local authorities have been planning for the adaptation and fortification of the site due to climate change (archived here).

Current and future threat

The rise of sea levels is a serious, persevering threat to humans and ecosystems.

NASA states that human activities have contributed to about 70 percent of the increase observed since 1970, with the percentage approaching 100 percent as time goes on (archived here).

Research from the Intergovernmental Panel on Climate Change (IPCC) shows a continued acceleration of sea-level rise (archived here).

Certain locations such as the Pacific island regions face greater risks than other places in the world and are projected to experience irreversible changes in the next 30 years, according to NASA (archived here).

An increase in the ocean watermark of nine inches (23 centimeters) over the last 125 years has shown to be enough to imperil many small island states and hugely amplify the destructive power of storm surges worldwide.

"Coastal ecosystems can migrate landward or grow vertically in response to SLR (sea-level rise), but their resilience and capacity to keep up with SLR will be compromised by ocean warming and other drivers, depending on regions and species," the IPCC noted in its 2022 report (archived here).

AFP has previously debunked other posts misrepresenting historical landmark photos to deny human-induced climate change and its impacts.