Mangroves in danger Henry Broadbent

The weekend of July 9–10 brought shocking pictures of the die-back of mangroves on the isolated shore of the Gulf of Carpentaria between Burketown and Karumba. While global warming was quickly suggested as to the cause, a more sober assessment suggested that drought was likely to be the culprit.

Westernport Bay has what I understand to be the most southerly mangroves in the world. Are we in danger of losing them? Particularly if the recent forecasts of imminent large sea level rises actually happen. Was it serendipity then that a notice arrived into my inbox on the very subject? Already primed I was intrigued to see an article published in the New Concepts in Global Tectonics Journal, by Albert Parker, titled: Darwin mangroves are not battling a sea level rise of +8.3 mm/year but increasing population and development. In the article, Albert Parker states: ‘We show here that the sea levels are rising in Darwin much less than the alleged +8.3 mm/year. Mangroves may suffer more from locally increasing population and development rather than the global carbon dioxide emission.’

Albert Parker detailed how a new Australian Authority took over tide gauging in 1991 and ‘after the ABSLMP was established, attention was shifted to the novel results neglecting prior and contemporary results from other sources.’ The article presents much information that leaves no doubt that the author is an expert on the subject. The article is freely available from V4,N2. Details are:

New Concepts in Global Tectonics Journal, June 2016, page 295-301. Albert Parker, School of Engineering and Physical Science, James Cook University, Townsville. Note: the journal is not peer reviewed.

I also searched and found archived the ABC report by Madeline Goddard that prompted Albert Parker to write his article. You can easily find it on the internet: Mangroves battling sea level rises. Goddard states: ‘But the harbour’s mangroves have been under threat by an annual average sea level rise of 8.3mm. This sea level rise is one of the highest in the world.’

The Australian Government Bureau of Meteorology National Tidal Centre (NTC) previously ran sea level surveys (for more than a century) but these ceased in Dec. 2013. Albert Parker states that the new body censored the last NTC Sea Level report of 2009. He seems concerned that the new authority does not appear to be competent.

The crux of the matter is that mean sea levels vary considerably due to pressure systems in the  atmosphere. In particular, ‘annual mean sea levels generally fluctuating in accordance with the Southern Oscillation Index (SOI)’ [Parker 2016]. At the time when the new authority took over tide gauging (1991) the sea level was at what is called a decadal low, and several mm lower than the average. It seems that this low level was not taken into consideration when the annual sea level rise was of 8.3mm was announced. From Parker’s presentation it is obvious that there is something basically wrong with the work of the new authority and in particular with that attention grabbing statement.

Albert Parker’s article is very technical and thorough; there is no doubt that he is correct in stating that worldwide there is no increase in the rate of sea level rise that stands about 2.1mm rise per year, as it has been for decades. There are signs that, if anything, the rate is decreasing. Don’t take my word for it; have a look at his article.

So if you have been concerned about reports of increasing sea level rise you can relax. Yes the sea level is slowly rising but there is no indication that there will be more than about 200mm rise over the next 100 years.

Leave Your Reply