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                                        Sea Level
                                and the The Seven Metre Surge! o

In 2007, the UN’s Intergovernmental Panel on Climate Change (IPCC) warned repeatedly that Arctic, Antarctic and Greenland ice will melt, snow on the mountaintops will be gone, sea ice will disappear, and ocean levels will rise seven metres (23 ft.) some thousands of years from now.

Skeptics might reasonably ask "How valid can such a distant forecast be?"

In the Toronto Star on March 25, 2007, science writer Peter Calamai declared that the seven metre surge will occur by the year 2100, less than a hundred years hence. His obvious confusion between a century and a millennium casts doubt on his further report that Global Warming has raised the mean sea level by one millimeter per year for several years past. That is about the diameter of a grain of rice or a drop of ocean spray each year.

With impressive credentials, and equal certainty, the scientific community tells us that mean sea level has risen not one, but two millimeters per year (2 drops of spray) for the last hundred years. Beyond the 100% discrepancy in those two views, other forecasters contend that the oceans will rise at five times that rate, 10mm per year (close to1/2 ") for the next hundred years. Wisely perhaps, they predict that most of that rise will occur in the last half of the coming century, which allows them a lag of 50 years before their estimates can be challenged.

Richard Peltier, a renowned professor of physics at the University of Toronto, is reported to be even more precise in his calculations. Eschewing oceanographers’ estimates that ocean levels rose 3mm per year from 1993 to 2005 (3 drops of spray), he narrows it down to 2.8 mm per year for that same dozen years. He attributes 1.0 mm of that to the expansion of warmer water; he traces about half a mm (0.5 mm) to melting glaciers and small ice caps; and a third of a mm (0.33 mm) to melting of the Greenland ice cap. That leaves 1.2 mm (a little over a grain of rice) to be accounted for. Perhaps the numbers can be re-worked?

                  If ocean surfaces are to be measured with such precision
                  against past levels, those past levels must be known with
                  equal precision.  But the ‘Permanent Service for Mean Sea
                  Level' based in Liverpool England at the UK Natural
                  Environmental Research Council (NERC) acknowledges
                  that mean sea level is far from being a well established
                  datum line.

For years the UK base line has been the Ordnance Datum Newlyn (ODN) observed at Newlyn, Cornwall from May 1910 to April 1921. Mean sea level in the Netherlands, Normal Amsterdam Peil (NAP) is indicated by a mark in the town hall. In France, a measure was taken years ago at Marseille, and many other countries have age-old but different reference points for sea level.

Historically, crude tide gauges have been used to measure sea level. These devices consist of a pipe, about a foot in diameter, fixed vertically to the side of a dock with the lower end submerged in the ocean. The bottom of the pipe is closed, save for a small hole that allows water to seep in and fill the pipe to the level of the surrounding ocean. The water level in the pipe rises and falls with the ebb and flow of the tide, but oscillations from waves are largely dampened out. The level is recorded regularly and averaged over months and years.

Such calculations have served well for practical purposes in the past, but at best, they are local approximations that provide a poor datum line for calculating precise change on a worldwide basis. Modern satellite observations now produce more accurate measurements, and computerized calculations may refine the averages, but still, the results cannot be more than approximations.

                  The average of any series of numerical data, requires
                  that all the components being averaged remain unchanged
                  throughout the averaging process.

But the level of the oceans is constantly undulating. It rises and falls endlessly, and unevenly across its vast extant, due to changing atmospheric pressure, evaporation and rainfall, hurricanes and storms, earthquakes, movement of tectonic plates on the ocean floor, ocean currents and undersea volcanoes that can send mountains of ocean spray tens of thousands of feet into the atmosphere. Sea level at Bermuda is about one metre (more than 3 ft.) higher than that along the northeast coast of the USA, due to the Gulf Stream. The Atlantic Ocean is about sixteen inches lower than the Pacific.

Normal intra-day tides throughout the world range from one to two metres (high to low) while that in Nova Scotia’s Bay of Fundy averages twelve metres high (almost 40 ft.) and sometimes reaches sixteen metres. (52 ft.).

Calculation of an average ocean level within fractions of a millimetre would require that measurements be taken simultaneously at virtually every point on the water's surface. It is reasonable to question if this has ever been or could ever be achieved,

                  That doubt suggessts that calculations showing a
                  millimetre change in mean sea level over the period
                  of a year are highly suspect. Surely, they reflect little
                  more than the computerized manipulation of a massive
                  array of questionable and constantly changing numbers,
                  with a result near zero.

It seems fair to say that scientists and others who make extravagant. long-range predictions about world conditions, based on short-term, variable data, are much like stock market analysts and horse-race enthusiasts. They can tell with certainty what happened today or yesterday, and explain why, but may be quite wrong about tomorrow As to the computer models they may rely on, it must be remembered that GIGO, the first law of computers, still applies; Garbage IN, Garbage OUT.