In a study of coral microatolls growing on reef flats of the Cocos Islands (96°52'E, 12°08'S), Smithers and Woodroffe (2001) reconstructed a history of sea level based on annual coral skeletal density bands manifest by X-radiography, supplemented by annual fluorescent bands made visible by ultra-violet light, from which it was determined, in their words, that "there has been little net rise in sea level in the eastern Indian Ocean during the 20th century."  In fact, mean sea level there, according to the coral data, rose only 2.3 to 3.3 cm.  This result is much lower than the 10- to 24-cm rise inferred for global sea level over this period from aggregate tide-gauge records corrected for postglacial rebound, but it is consistent with results obtained over the past decade from TOPEX satellite altimetry for a 2° x 2° grid centered on the Cocos Islands.  In this regard, Smithers and Woodroffe state that "the significance and persistence of the accord between the TOPEX and microatoll sea-level signal for Cocos and their mutual divergence from prevailing 'global' sea-level rise trends cannot yet be resolved with the available data."  Until this discrepancy is resolved, therefore, it would probably be wise to withhold judgment on this important topic, for we may well find that low-lying coastal areas and islands may not be in nearly as great a danger of being submerged as many climate alarmists are claiming.

In another Southern Hemispheric study, Bryden et al. (2003) note that "with so few repeat observations, there has been a tendency to treat any observed change in water mass properties or circulation as an indicator of ocean climate change."  Hence, in a compelling exercise that demonstrates the great danger of this almost irresistible urge, they compare five Indian Ocean hydrographic sections across 32°S that were made in 1936, 1965, 1987, 1995 and 2002.

The results of their study, in their words, clearly indicate "there has been an oscillation in the water mass properties of the upper thermocline waters with freshening from 1965 to 1987 and then an increase in salinity from 1987 to 2002, with the properties observed in 2002 close to those observed in 1936 and 1965."  They further note that these changes demonstrate "there can be substantial oscillations over decadal time scales," and that "without regular observations, oceanographers have little understanding of the scales of variability in water mass properties."  Indeed, they note that the most recent change "almost entirely reverses the observed freshening of mode waters from the 1960s to 1987 that has been interpreted to be the result of anthropogenic climate change on the basis of coupled climate models."

Clearly, many people have been much too quick to jump on the CO2-induced global warming/rising sea level bandwagon.  The existing oceanic data pertaining to this problem are just too few and far between to answer the climate change questions on everybody's minds.  We must remember that patience is a virtue; and we are going to need a whole lot of it throughout the future decades of data acquisition that will be required to definitively resolve this issue.

Within this same context, Baker and Haworth (2000a,b) present substantial evidence that sea-level, as measured over large portions of the Southern Hemisphere, has declined significantly since approximately 6,000 years ago.  But has the journey been smooth or oscillatory?  In attempting to answer this question, they reviewed data, including much of their own, obtained from a number of different places in the non-glaciated, tectonically-stable regions of the Southern Hemisphere.

For the period 6000 to 600 years before present, they demonstrate that an oscillatory mode of sea-level decline is just as likely to have occurred, in terms of "statistical justification" based on the available data, as a smooth decline.  As they describe it, "whether or not sea level has been subject to low-amplitude fluctuations during the late Holocene (the last ~ 6000 years) is a subject that has taken on increased importance in view of claims of possible sea-level rise associated with human-induced global warming."  If, for example, sea-level has oscillated somewhat over this period (Baker and Haworth say it could have had an oscillatory amplitude of one meter or more!), it is possible that the sea-level's current modest rising mode may be nothing more than a small portion of a natural oscillation having nothing to do with the ongoing rise in the air's CO2 content.  The finding that this type of sea-level behavior is just as likely to be true as not thus casts a pall of suspicion over climate-alarmist claims that the continued burning of fossil fuels will lead to the inundation of low-lying coastal areas and islands.

In light of these observations, we can draw some important conclusions about the way we should approach the future.  First, there are those who claim the continued burning of fossil fuels is nigh unto criminal, because of what they claim this course of action will ultimately mean for coastal lowlands and islands, i.e., their submergence beneath the sea.  But if they are wrong about the cause of the warming, which they believe to be the cause of the sea-level rise - and this study says there's a fifty-fifty chance they are wrong on the last point alone - the actions they would have us take could be viewed as criminal; for reducing CO2 emissions would give the inhabitants of the threatened regions a false hope of security that would ultimately be dashed by the inexorable natural rising of the sea, and at a time when it may be too late to do anything about it, especially if the global economy suffers irreparable harm from misguided energy policies that could leave it too weak to help avert the human tragedy that would likely accompany a sea-level rise of the magnitude the data of these studies suggest is possible.

This being the case, the Precautionary Principle would seem to suggest that the nations of the world should begin preparing now for a sea-level rise of precisely the type climate alarmists are ranting and raving about, not in terms of trying to avert it, especially by incredibly disruptive measures that could well have absolutely no effect upon it, but in terms of adapting to it in some way, hopefully in advance and not in retrospect.  To do anything else, and especially something that has no impact whatsoever upon the problem and costs us dearly in terms of human and natural resources, is more than just illogical.  It is, as they say, criminal.

References
Baker, R.G.V. and Haworth, R.J.  2000a.  Smooth or oscillating late Holocene sea-level curve?  Evidence from cross-regional statistical regressions of fixed biological indicators.  Marine Geology 163: 353-365.

Baker, R.G.V. and Haworth, R.J.  2000b.  Smooth or oscillating late Holocene sea-level curve?  Evidence from the palaeo-zoology of fixed biological indicators in east Australia and beyond.  Marine Geology 163: 367-386.

Bryden, H.L., McDonagh, E.L. and King B.A.  2003.  Changes in ocean water mass properties: Oscillations or trends?  Science 300: 2086-2088.

Smithers, S.G. and Woodroffe, C.D.  2001.  Coral microatolls and 20th century sea level in the eastern Indian Ocean.  Earth and Planetary Science Letters 191: 173-184.