No Acceleration of Global Sea-Level, II

Stuart Rintoul, in The Australian, reveals that despite our Government’s hysterical claims that the world’s sea-levels will rise alarmingly, a government expert explains that the rises are decelerating.   In “Sea-level rises are slowing, tidal gauge records show”, Rintoult writes:

One of Australia’s foremost experts on the relationship between climate change and sea levels has written a peer-reviewed paper concluding that rises in sea levels are “decelerating”.

The analysis, by NSW principal coastal specialist Phil Watson, calls into question one of the key criteria for large-scale inundation around the Australian coast by 2100 – the assumption of an accelerating rise in sea levels because of climate-change.

Based on century-long tide gauge records at Fremantle, Western Australia (from 1897 to present), Auckland Harbour in New Zealand (1903 to present), Fort Denison in Sydney Harbour (1914 to present) and Pilot Station at Newcastle (1925 to present), the analysis finds there was a “consistent trend of weak deceleration” from 1940 to 2000.

Mr Watson’s findings, published in the Journal of Coastal Research [...] supports a similar analysis of long-term tide gauges in the US earlier this year.  Both raise questions about the CSIRO's sea-level predictions.

Climate-change researcher Howard Brady, at Macquarie University, said yesterday the recent research meant sea levels rises accepted by the CSIRO were “already dead in the water as having no sound basis in probability”.

“In all cases, it is clear that sea-level rise, although occurring, has been decelerating for at least the last half of the 20th century, and so the present trend would only produce sea level rise of around 15cm for the 21st century.”

Dr Brady said the divergence between the sea-level trends from models and sea-level trends from the tide gauge records was now so great “it is clear there is a serious problem with the models”.

“In a nutshell, this factual information means the high sea-level rises used as precautionary guidelines by the CSIRO in recent years are in essence ridiculous,” he said.  During the 20th century, there was a measurable global average rise in mean sea level of about 17cm (plus or minus 5cm).  [...]

The federal government has published a series of inundation maps [...] showing that large areas of Australia’s capital cities, southeast Queensland and the NSW central coast will be under water by 2100.

Without acceleration in sea-level rises, the 20th-century trend of 1.7mm a year would produce a rise of about 0.15m by 2100.

Mr Watson’s analysis of the four longest continuous Australian and New Zealand records is consistent with the findings of US researchers Robert Dean and James Houston, who analysed monthly averaged records for 57 tide gauges, covering periods of 60 to 156 years.

The US research concluded there was “no evidence to support positive acceleration over the 20th century as suggested by the IPCC, global climate change models and some researchers”.

See P.J. Watson, “Is There Evidence Yet of Acceleration in Mean Sea Level Rise around Mainland Australia?” in the Journal of Coastal Research. 

See also our “No Acceleration of Global Sea-Level, I” and, at WUWT, “The battle over sea level”.