John Le Mesurier’s recent article in On Line Opinion, "The Creeping Menace", re-hashes the alarmism about rising sea levels. Much has happened, however, since Al Gore scared the world with visions of metre high seas flooding New York.
First, there is still no proof the Earth is experiencing “dangerous” warming. Temperatures have levelled off since 1998. Many measuring locations are also located in unsuitable areas. Furthermore, the methodologies of averaging temperature are inconsistent and full of problems. This is why “Global Warming” was replaced as a slogan by “Climate Change” (nobody denies that climate changes), and more recently by “Climate Disruption” (which is impossible define or prove).
Second, the increased temperature is supposed to increase sea level mainly by melting the ice-caps, which is impossible. Thermal expansion of the oceans seems to be of little consequence at present because the satellite measurements show the oceans are cooling. Le Mesurier gilds his picture with a few asides on “extreme climatic events” in general and hurricanes in particular. Recent studies, however, show no increase in hurricane activity in the last 40 years.
With regard to sea level, I have come to the view the IPCC and Australian Bureau of Meteorology, run by CSIRO, are unreliable sources of data after critically assessing their statements on this subject for some time. Direct studies of sea level are showing only small rises. You can see the sea level data for yourself for the United States and a few other countries here. Most stations show a rise of sea level of about 2mm per year, but note the considerable variation even within a single state.
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 (expressed in CO2 equivalent). Usage of all known fossil fuel reserves would only achieve half of this and continuation of the current rate of increase in concentration levels would result in only 550ppm by 2100.
In terms of sea levels, the result is a CSIRO predicted rise for Port Phillip Bay by 2100 of 82cm and, with the help of the Bureau of Meteorology, an increase due to wind to 98cm. That is not only well above even the top level projected by the latest IPCC report but is also well above any projections from the last 20 to 100 years.
Two favourites of sea level alarmists are Tuvalu and the Maldives. Sea level measurements for Tuvalu (and 10 other stations) between 1992 and 2006 are available on Fig. 13 on the Australian Bureau of Meteorology website (PDF 1.97MB). For about the past eight years the sea level seems to be virtually constant. Vincent Gray has reviewed the evidence and finds virtually stable sea levels in the South West Pacific, and he also discusses how the data have been manipulated to suggest rising sea level.
Sea level in the Maldives was studied in enormous detail by the doyen of sea level scientists, Niklas Axel-Mörner. His team determined the sea level curve over the past 5,000 years based on evidence of morphology, stratigraphy, biology and archaeology supported by extensive C14 dating, and found that “All over the Maldives there is evidence of a sub-recent sea level some 20cm higher than the present one. In the 1970s, sea level fell to its present position.” (My italics.)
Incidentally a recent study of coral islands in the Pacific by Webb and Kench showed the islands are actually growing larger despite any possible sea level rise.
Holland is very low and would be particularly vulnerable to any large rise of sea level. It is also a world leader in coastal study and engineering, and the Dutch are not alarmed. In the December 11, 2008, issue of NRC/Handelsblad (Rotterdam’s counterpart to The Australian or The Age) 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 twenty centimetres. There is no evidence for accelerated sea-level rise. It is my opinion that there is no need for drastic measures. Fortunately, the time rate of climate change is slow compared to the life span of the defense structures along our coast. There is enough time for adaptation.
What about the alleged cause of most of the scary sea level rise - the melting of ice-caps? This idea of rapid loss of ice is based on the concept of an ice sheet sliding down an inclined plane on a base lubricated by meltwater, which is itself increasing because of global warming.
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