New evidence from one of the world’s oldest sea-level measurement sites in Australia suggests that the oceans are not rising as fast as previously thought. Climate change may be overrated.
In the 20th century, the oceans rose by slightly less than an inch per decade, according to the UN Intergovernmental Panel on Climate Change (IPCC), and the current consensus is that manmade global warming will make them rise even faster due to thermal expansion.
However, a few stubborn voices challenge this view. One of these is Australian amateur scientist and vocal climate skeptic John Daly, who made a fascinating report about an old sea-level benchmark in Port Arthur, Tasmania. Based on measurements done over an extended period, Antarctic explorer Sir James Clark Ross struck a mark on the Isle of the Dead in 1841 to document the average sea level.
Now, nearly two centuries later, the mark is still visible, suggesting that there has been little or no sea-level rise. Mainstream scientists dismissed it as an error and gave it little attention.
Then almost two decades later, hydrographic surveyor Daniel Fitzhenry told Sky News Australia that sea-level data recorded by the Bureau of Meteorology (BOM) at Fort Denison in Sydney Harbor is “more accurate than satellite.”
Just like the Isle of the Dead, Fort Denison is a geologically stable island. Fitzhenry said that it remains one of the longest and most reliable sea-level records in the world due to its proximity to the Pacific Ocean.
BOM started its mean sea-level measurements at Fort Denison in 1914, and the level has fluctuated in a range of six inches since then. Amazingly, the sea level in 2019 is 2.5 inches lower than 105 years earlier.
With the Fort Denison data corroborating the Tasmanian Isle of the Dead record, the latter can no longer so easily be dismissed as a fluke. Two geologically stable sites facing the vast expanse of the Pacific Ocean show similar trends.
Most people are unaware that satellites are calibrated to land-based measurements. Nils-Aksel Mörner, a retired Swedish scientist and former president of the International Union of Quaternary Research (INQUA) Commission on Neotectonics, has pointed out that, before calibration, the satellites showed no sea-level rise. His work on the Maldives indicated that the oceans were falling in recent decades, not rising.
Such calibration is problematic because most tide gauges in the world are located near cities on soft land. As cities grow, massive buildings and groundwater depletion results in the urban areas sinking and the tide gauges along with them. The most famous example of this is Venice in Italy that has been sinking for centuries.
What makes Fort Denison stand out is that, in addition to being exposed to the Pacific Ocean and having an exceptionally long measurement record, it is also geologically stable. It doesn’t sink. Therefore, it may indeed be more accurate than the erroneously calibrated satellite data.
The consequence would then be that the oceans are not rising as much as previously thought and would require a rethinking of the danger that alleged climate change posits. Fort Denison teaches us the importance of building a science on solid ground.