Trends in sea level at Townsville, Great Barrier Reef

Sea level at Townsville, Great Barrier Reef, Queensland

Dr. Bill Johnston[1]

http://www.bomwatch.com.au/

(scientist@bomwatch.com.au)

Main points

  • If melting of glaciers and icesheets in Greenland in recent decades significantly influenced mean sea level (MSL) it would be detectable in data for Cape Ferguson from 1991 and Townsville Harbour from 1959. However, there was no evidence that climate change, warming or melting ice sheets has caused sea levels to increase.
  • Tide gauges are affected by the conditions under which they operate. Data are coarse, imprecise, poorly documented and not understood by climate scientists and oceanographers who routinely conflate variation caused by covariates such as the El Niño Southern Oscillation, components of local water balances, and step-changes caused by site and instrument changes as being due to the climate.
  • In order to draw valid conclusions, it is imperative that scientists implement a quality assurance process that distinguishes between variables that cause variation IN data (covariables), from those that impact ON the data-stream (impact variables) and adjust for those using independent statistical methods.
  • Scores of peer reviewed papers published at great expense in elite scientific journals, by multiple authors supported by long reference lists are biased by lack of attention to detail and poor science. Using Cape Ferguson as a case study, and replicated using data for Townsville Harbour, the approach outlined here, which is widely applicable, sets a benchmark for undertaking due diligence on data. Findings of papers that failed to assess the fitness of data used to determine trend and change should be disregarded.

Background

Australia’s lead management agency for the Great Barrier Reef, the Great Barrier Reef Marine Park Authority (GBRMPA) states on their website that “global average sea level rose by 0.18 centimetres per year from 1961 to 2003. The total rise from 1901 to 2010 was 19 centimetres, which is larger than the average rate during the previous 2000 years.” (https://www.gbrmpa.gov.au/our-work/threats-to-the-reef/climate-change/sea-level-rise).

Further, they say that “Since 1959, records of sea levels for Townsville, in north Queensland, show an average increase of 1.2mm per year. However, the rate of increase may be accelerating, with records of sea levels at Cape Ferguson near Townsville showing an average increase of 2.9mm every year between 1991 and 2006.” How can it be that for the same waterbody, sea level is increasing 2.5 times faster just 25 km away from Townsville Harbour at Cape Ferguson?

GBRMPA goes on to claim that “because much of the land adjacent to the Great Barrier Reef is low-lying, small changes in sea level will mean greater erosion and land inundation. This will cause significant changes in tidal habitats, such as mangroves, and move saltwater into low-lying freshwater habitats. This will have flow-on effects for juvenile fish that use these habitats for protection and food resources.” So how can that be that compared with current satellite imagery aerial photographs from the 1950s and 1960s show wetting fronts on beaches and tidal influences on rocky headlands such as Cape Cleveland are unchanged?

Paid for by taxpayers, led by government agencies including CSIRO and the Bureau of Meteorology, ably assisted by the Australian Institute of Marine Science (AIMS) and barracked-on by slick campaigns run by WWF, the Climate Council, the Australian Museum, the Great Barrier Reef Foundation et al., Australians are bombarded by confusing, over-hyped mis-information and scare-campaigns related to the Great Barrier Reef.

Disaster-porn has replaced knowledge and understanding to the point that Australia’s climate history has been substantially re-written. Like a billion-dollar cart of hay put before the science-horse, in almost every sphere, policy-driven science has overtaken the scientific method.

Coupled with previous exposés that showed apparent trends in maximum temperatures at Cairns, Townsville and Rockhampton were caused by homogenisation adjustments and not the climate [LINK], this series of investigations examines monthly sea-level data measured at Cape Ferguson since September 1991 and the longer record for Townsville Harbour since January 1959. The aim is to independently verify that due to anthropogenic warming, survival of the Great Barrier Reef is imperilled by compounded multiple threats including sea-level rise. Of overriding concern is that on behalf of their ‘independent’ boards and sponsors, scientists may have been led astray by liberally-scattered golden-hay, and thereby lost pride in their scientific work.

What we did

Using the 30-year monthly MSL dataset for Cape Ferguson as a case study, we objectively distinguished between variables that cause variation IN tide-gauge data (covariables) from those that impacted ON the data-stream (impact variables). The approach outlined in the paper provides climate scientists and oceanographers with a method for verifying that data they use is fit for purpose i.e., that trend reflects the oceanographic waterbody and not covariables and/or effects caused by site and instrument changes. The Cape Ferguson study was replicated using the 62-year monthly dataset for Townsville Harbour.

Principle findings

  • At Cape Ferguson, 31.9% of variation in MSL was accounted for by (in order of importance), SOI3pt; barometric pressure (hPa); lag1 solar exposure (MJ/m2); Lag2 rainfall (mm), and current rainfall. Accounting for a step-change in 2009 caused by a change in calculating 10-minute values from 1‑second samples, and a residual 18.06-year cycle, increased R2adj to 0.645 (64.5%). Having removed variation IN the data and the effect of the inhomogeneity ON the data-stream, no trend or change was attributable to any latent factor such as melting glaciers and icecaps in Greenland, coal mining or global warming. 
  • The dataset for Townsville Harbour from January 1959, was nosier than Cape Ferguson, partly because data before 1984 were manually digitised from tide gauge charts and also because water levels in the harbour, which lies at the entrance to Ross Creek are greatly influenced by hydrological processes within the catchment, including urban development, irrigation, leakage etc. Thus, while SOI3pt was less influential, components of the water-balance (rainfall, evaporation and seasonality) were more so. Significant covariables accounted for 25.3% of variation in MSL.

Step-changes in residuals aligned with construction of the Ross River Dam in 1971 and its enlargement 2007. A third inhomogeneity in 1987 may have been associated with harbour developments or an undocumented change related to the gauge. Significant variables and step-changes together accounted for 49.2% of MSL variation.

  • Although MSL data were affected by random noise no residual trends or changes were due to any other systematic factor including warming of the climate or the ocean.

The full report can be downloaded [HERE].


[1] Former NSW Department of Natural Resources research scientist.

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