Uncertainties Over Sea Level Rise
The New Zealand
Climate Science Coalition
3 December 2014
Uncertainties Over Sea Level Rise
by Joe Fone*
The recent alarmist claims of rapid sea level rise issued by Parliamentary Commissioner for the Environment Dr. Jan Wright warrant closer scrutiny.
Dr. Wright claims that a sea level rise of 30cm by 2050 in New Zealand is “inevitable”. That rise amounts to an average of 8.3mm per year, which is more than five times greater than the global average trend since 1900 of 1.6mm/year, which is attributed to the planet gradually emerging from the Little Ice Age.
By claiming such an outcome as “inevitable”, Dr. Wright has clearly accepted as gospel the worst-case, most speculative scenario offered by the IPCC (U.N. Intergovernmental Panel on Climate Change). Such speculations are based entirely on models (computer programs) and ignore measurements taken from tide gauges. The “Seaframe” series of tidal gauges, for example, installed throughout the South Pacific by Australia in the early 1990’s shows negligible long-term change.
The dire predictions in the report released by Dr. Wright ignore that observations using tide gauges, satellite altimeters, and gravitational sensors, as well as calculated sea level rise from measurements of ocean temperature and salinity; all indicate adecrease in the global rate of sea level rise this century. They also ignore the fact that sea level change varies with location, probably due to ground movement. The US National Oceanographic and Atmosphere Administration (NOAA) reports that along California’s coast the sea level is rising by up to 3.9mm/year, but Alaska’s south coast is falling by up to 17.6mm/year. Further, one tidal gauge in Hawaii shows a rising trend more than double the trend in another location in Hawaii.
In recent times any regional storm surge and local flooding event is attributed to rising sea levels, just as every flood, drought, blizzard and heat wave is claimed to be evidence for manmade global warming. The evidence to support such claims is slim because these events have also happened in the past and any attempted links to greenhouse gas concentrations are very speculative and convoluted.
Ground subsidence in eastern Christchurch, after the series of large earthquakes that began in September 2010, easily accounts for flooding there. Sea level rose because ground subsided, not the supposed warming due to greenhouse gases.
By contrast with the Commissioner for the Environment, world-renowned sea level expert Dr. Nils-Axel Mörner, formerly chairman of the INQUA International Commission on Sea Level Change, who has studied global sea levels for decades using various empirical measuring techniques, and who has written over 600 papers on the subject, describes the predictions of catastrophic sea level rise as the biggest lie ever told. He blames this on the unfortunate reliance on modelling rather than on measurements and says that the global average sea level is not rising any more than what is expected naturally.
Mörner's “worst-case” prediction for seal level this century is that the rise will “not be more than 10cm (four inches), with an uncertainty of plus or minus 10cm”. This is vastly lower than Dr. Wright’s dire expectations of 30cm by 2050.
In any case, mitigation against sea level increase is not necessarily an expensive and complicated process requiring the intervention of regional councils to issue draconian and restrictive dictates against property owners. Such a simple expedient as dune restoration has immediate benefits.
A century ago, flooding of our coastline was more severe than today, even though sea level was lower. The reason for the decrease in the frequency and severity of coastal flooding since then is that our forebears adapted and mitigated the effects of storm surges and extreme tides (and sea level rise) by reclaiming low lying land and building stop banks (dykes). Their foresight at the time prevented erosion and property damage from occurring decades into the future. The politicians however seem to assume that we are now incapable of doing the same.
Interestingly, the exaggerated claims of accelerated sea level rise are similar to outlandish claims over global temperatures which are projected to increase sharply as carbon dioxide emissions increase. These claims too are based on climate model outputs and bear no resemblance to reality.
Again, temperature measurements taken by satellites, which have the advantage of covering most of the planet, show a stark divergence with the models over the past two decades or more, and indicate no discernible warming trend at all for the past 18 years despite the amount of carbon dioxide in the atmosphere. We are now told to believe that at some point in those 18 years, heat started hiding itself away in the deep ocean, somehow dodging around all instruments that might record it at the Earth’s surface.
Dr. Wright’s report extends on this by claiming that the “missing heat” will eventually emerge from the ocean depths to cause havoc and increase sea levels well into the future. However, a recent paper from NASA scientists showed that the deep ocean is not warming and therefore that the notion that the “missing heat” playing hide-and-seek is a spurious nonsense.
Contrary to Dr. Jan Wright’s dire warnings of catastrophic sea level rise in the near future, the good news is that empirical measurements show that the seas are behaving perfectly normally. Nature is doing what Nature does. The belief that catastrophic temperature and sea level rise is “inevitable” based on predictions derived entirely from models that are clearly diverging from reality is also a nonsense.
*Joe Fone is a member of the New Zealand Climate Science Coalition and author of Climate Change: Natural or Manmade?He has written numerous articles on climate change, science and other subjects over the years for various newspapers and magazines.