Via Warwick Huges | Errors in IPCC climate science :
In 2012 I blogged To understand Perth sea-levels is a complex issue – much of the Perth plain has subsided in recent decades…
Recent media publicity around a “State of Australian Cities” reporthas beaten up claims that Perth sea-levels are rising at three times the global average, or near 10mm per year. A matter that Federal Infrastructure Minister Anthony Albanese described as “disturbing and extraordinary”. Chris Gillham shows that the claims in the State of Australian Cities report re Perth sea level rise are over-hyped.
This chart fom a 2010 WA Govt planning report shows long term sea level changes at Fremantle.
The State of Australian Cities report concentrates on shorter term more sensational trends in the last 20 years but omits to quote recent research measuring rapid subsidence of large areas of the Perth coastal plain.
A 2012 paper – Anthropogenic land subsidence in the Perth Basin: challenges for its retrospective geodetic detection – says subsidence at Gnangara for the 14 years 1997-2011 has averaged 4.6mm per year – see Table 1 below.
In recent decades subsidence has been worsened by increased drawdown ground water for Perth water supplies – a process which has eased post 2005.
This online chart shows CGPS readings from the Hillarys tide gauge installation and indicates steady sinking of ~3mm per year 2006-2012. There are no CGPS readings I can find from Fremantle.
Hillarys has CGPS data from 1997 and Featherstone et al say those data – “…are not in a form that can be readily analysed in a short time frame, particularly because of the multiple equipment changes that make the time series very discontinuous.” Other published versions of the Hillarys CGPS data quote a 1998-2009 subsidence averaging just over 5mm per year. Watson PJ – Is There Evidence Yet of Acceleration in Mean Sea Level
Rise around Mainland Australia?
Journal of Coastal Research, Vol. 27, No. 2, 2011
Featherstone et al 2012 discuss surveying to detect level changes and say – “There is some scope for detecting subsidence in the Perth Basin if levelling is repeated now or sometime in the future. However, the costs are likely to be prohibitive.”
I fail to see how a few repeat levelling traverses from the Darling Ranges to the coast costing what ? – a few $million ? – should be beyond the wealth of a First World nation like Australia. Apparently some traverses were carried out in the 1980’s.
There is no shortage of Govt grant monies to waste on shonky Greenhouse inspired “research”.
Tide gauges and harbours are often located in places where the crust is sinking due to say sedimentation from a river. Any harbour structure attached to piles will slowly sink into the muddy substrate over the decades – factors like traffic vibration, a century of ships banging into piles – all can contribute to piles sinking. Dock areas where tide gauges tend to be installed are often the sites of reclaimed land, Auckland is an example. This tends to quietly settle for decades which can confound tide gauge data. At Fremantle 150 years of urbanization – including storm-water drainage direct to the sea – can lower ground water levels and cause subsidence – quite apart from deliberate ground water harvesting.
See also :
CORALS evolved during the Cambrian era when atmospheric CO2 levels were at 6,000-7,000 ppm, around 4,000 percent or 20 times higher than today’s “CO2-starved” environment of 400 ppm, with atmospheric and ocean temps temps far higher than today.
CORALS have survived millions of years of dramatic and sudden climate change, yet climate alarmists want us to believe that a few hundred ppm more atmospheric CO2 is going to end us!?
CORAL bleaching is a naturally occurring phenomenon essential to the health and regrowth of coral reefs.
THE “Great Barrier Reef” is only “great” because it has died off at least 7 known times over the millennia.
CORAL reef fear-mongering is another man-made lie to push the man-made global warming aka climate change scam…
Guest essay by Eric Worrall
h/t JoNova – the Australian ABC reports scientists from the Australian Institute of Marine Science are surprised how rapidly the Australian Great Barrier Reef is recovering from the 2016 bleaching event.
Great Barrier Reef starts to recover after severe coral bleaching, survey of sites between Cairns and Townsville shows
By David Chen
Updated Fri at 3:41pm
Scientists from the Australian Institute of Marine Science this month surveyed 14 coral reefs between Cairns and Townsville to see how they fared after being bleached.
The institute’s Neil Cantin said they were surprised to find the coral had already started to reproduce.
“We’re finding corals that are showing early signs of reproductive development, really visible eggs that we can see under the naked eye,” Dr Cantin said.
“[It’s] very surprising as previous studies have shown a two-to-three year delay in reproductive activity following bleaching events.
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