Guest post by Cliff Ollier
The Australian (March 24) reports that Port Macquarie Hastings Council is recommending the enforcement of a “planned retreat” because of an alleged danger from sea level rise in the distant future. The controversy about moving people from near-shore sites raises two questions: is the alarming rise in sea level projected by CSIRO reliable, and is moving people the correct response?
The CSIRO projection is in fact extreme. Before explaining why, I should like to note that the world’s main source of alarmism is the IPCC. This is not really a scientific body, but one that adjusts data and subjects it to mathematical modelling before passing its ‘projections’ on to politicians. The IPCC is followed by the CSIRO and Bureau of Meteorology, who further adjust data and produce more models with even more extreme scenarios.
In the Weekend Australian (7 November 2009), Bill Mitchell, Director of the National Tide Centre of the BoM, reported Australian average sea level rise of 1.7 mm/yr. This is a reasonable level accepted by most sea-level watchers outside IPCC and CSIRO. It gives a sea level rise of about 15 cm by 2100. Mr. Mitchell said the “upper end was 3 mm/yr” – a 27 cm rise by 2100.
At 8.30 am on 18 November 2009, ABC Radio National had a program on sea level changes. Alan Stokes, Director of the Sea Level Task Force, said: “The IPCC estimate of rise to 2100 was up to 80 cm.” No new data were provided to explain the leap. In fact, the worst estimate of IPCC in its last report was 59 cm.
Note that the IPCC estimates have been falling with each report. In the Second Assessment Report, the high-end projection of sea-level rise to 2100 was 92 cm, in the Third Assessment Report 88 cm, and in the Fourth Assessment Report 59 cm.
It is good for the reader to look at sea level measurements personally. You can see for yourself the sea level data for the United States and a few other countries at http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml. Most stations show a rise of sea level of about 2 mm per year, but note the considerable variation even within a single state, though these are no cause for alarm.
The CSIRO uses figures far in excess of even the IPCC, who until now were the greatest alarmists. In their 2012 report, State of the Climate, they say that since 1993 sea level has risen up to 10 mm per year in the north and west. That means that some place has had a 19 cm rise in sea level since 1993. Where is this place? Meanwhile, the European Envisat satellite shows that sea level has scarcely risen for the last eight years.
How do the CSIRO arrive at their figures? Not from any new data, but by modelling. Models depend on what is put into them. For example, a 2009 report by the CSIRO for the Victorian Government’s Future Coasts Program on The Effect of Climate Change on Extreme Sea Levels in Port Phillip Bay based its model on temperature projections to 2100 of up to 6.4 degrees. That is the most extreme, fuel-intensive, scenario of the IPCC and implies unbelievable CO2 concentration levels in 2100 of approximately 1550 parts per million. Usage of all known fossil fuel reserves would only achieve half of this. Continuation of the current rate of increase in CO2 concentration levels would result in only 550 ppm by 2100.
The result is a CSIRO prediction of sea level rise for Port Phillip Bay by 2100 of 82 cm and, with the help of the Bureau of Meteorology, a further increase to 98 cm attributable to the wind. That is well above even the highest level projected by the latest IPCC report.
This example is from Victoria, not New South Wales, but sea level must have roughly the same rises and falls all over the world. So the whole world should be alarmed, not just New South Wales. Indeed the IPCC and CSIRO try to alarm the world with stories of drowning of low islands, like Tuvalu. But detailed mapping has shown that Tuvalu, and many other coral islands, have actually grown over the past 20 years.
Holland is very low and is particularly vulnerable to any large rise of sea level. It is also a world leader in coastal science and engineering, and the Dutch are not alarmed. In the December 11, 2008, issue of NRC/Handelsblad (Rotterdam’s counterpart to the Australian), Wilco Hazeleger, a senior scientist in the global climate research group at the Royal Netherlands Meteorological Institute, wrote:
“In the past century the sea level has risen 20 cm. There is no evidence for accelerated sea-level rise. In my opinion there is no need for drastic measures. Fortunately, the rate of climate change is slow compared to the life-span of the defense structures along our coast. There is plenty of time for adaptation.”
This brings us to the second part of the debate. We should adapt to changes in the shoreline, like the Dutch. We should reject draconian rules to save folk from a remote and dubious peril. If Tim Flannery, Australia’s chief climate commissioner, is allowed to take his chance living on his Hawkesbury property near sea level, Port Macquarie’s retirees should be permitted to do so too. They should not be evicted to “save” them from a dire fate in a future they will never see.