Posted on 01/23/2003 2:11:40 PM PST by cogitator
Long-Lost Records Confirm Rising Sea Level
Hobart - Jan 22, 2003
The discovery of 160 year old records in the archives of the Royal Society, London, has given scientists further evidence that Australian sea levels are rising with an estimate of 16 centimeters since 1890.
Observations taken at Tasmania's Port Arthur convict settlement 160 years ago by an amateur meteorologist have been compared with data from a modern tide gauge.
"There is a rate of sea level rise of about 1mm a year, consistent with other Australian observations," says Dr David Pugh, from the UK's Southampton Oceanography Centre.
"This is an important result for the Southern Hemisphere, and especially for Australia, providing a benchmark against which Australian regional sea level can be measured in 10, 50 or 100 years time," says Dr Pugh.
Working with Dr Pugh on the three year project were the University of Tasmania's Dr John Hunter, Dr Richard Coleman and Mr Chris Watson.
In 1837, a rudimentary tide gauge was made by the amateur meteorologist, Thomas Lempriere and probably installed in the nearby Port Arthur settlement.
In 1841 Lempriere cut a benchmark, in the form of a broad arrow, on a vertical rock face on the Isle of the Dead, which was used as a cemetery for the Port Arthur complex.
The discovery of two full years of carefully recorded measurements (1841 and 1842) of average sea level was the start of a scientific quest through early European history in Tasmania.
CSIRO oceanographer Dr Bruce Hamon, researching Lempriere's work in 1985, concluded that the surviving benchmark would not be of scientific value today.
"The position of course would be different if Lempriere's original observations ever came to light," Dr Hamon wrote.
In addition to discovering the 'lost' files, the project involved analysis of 19th century sea level data, and a suite of modern measurement and analysis techniques.
Dr Hunter said that scientific and popular interest in possible rises of global sea level, with attendant increased risks of coastal flooding have emphasised the need for a long time series of sea level measurements.
"Unfortunately, few records exist from the nineteenth century, and even fewer have well documented benchmark information against which changes can be monitored.
"At Port Arthur we have a unique series of sea level measurements.
"Our research during this project has shown that the work of John Franklin, James Clark Ross and Thomas Lempriere generated a significant benchmark long before any effect of global warming was apparent.
"The scientific interest at the time was the question of vertical motion or uplifting of the continents rather than changes in volume of the oceans.
"Our observations are consistent with the lower end of estimates by the Intergovernmental Panel on Climate Change and with records from Fremantle and Fort Denison," Dr Hunter said.
Measurements have been taken at Fremantle in Western Australia for 91 years and at Fort Denison, Sydney for 82 years.
Yes, yes, I know. (What we don't know is how much and how fast it's happening now.)
The researchers used the position of a nearby fossil shell bed to address this.
That's what happened with the Himalayas. The subcontinent of India plowed into Asia a few million years ago, and the Himalayan uplift resulted.
Very few people dispute that sea level has changed in Earth's paleohistory. The question of concern now as regards to climate change is how much it is changing and how much higher it might rise. As the storm-battered residents of Fiji and the Solomon Islands might tell us, a couple of centimeters means a lot when your island is only a couple of feet higher than the ocean.
Regardless of what mean sea level is/was the fact remains:
"What is so fascinating is that the mark appears to some to be 30 centimetres above the current mean sea level."or photographable at all after 160 yrs. of global warming....OH that's right, I forgot. Up untill the 1970's we were entering an ice age, the dyslexic sceintists suddenly changed that scare tactic to "global warming".
Short answer to the question posed above: No.
Regarding the mark, if the CSIRO research is accurate, then the position of the mark is consistent with an approximately 16 cm sea level rise around Australia since the late 1800s. If the mark was not placed at mean sea level then, its position now - above or below mean sea level - doesn't mean anything.
The global warming crowd tries to tie sealevels to climate. It's a scare tactic to make people think we will all drown if we drive suvs.
To believe that the measurement in this article are accurate one must believe that the rock in Port Arthur is the same distance from the center of the earth as it was in 1890, that because the sea is 16 centimeters higher in relation to the rock that the sea rose.
While most people believe that the ground we walk on is rock solid, the truth is it is nothing more than debris floating on a liquid core. GPS data shows that the Himalayas are still rising over an inch a year. But we don't have anything that could accurately measure the altitude of Port Arthur in 1890 to within 16 centimeters.
Climate does effect sea levels but erosion of the lands filling the seabeds with sediment probably increased sea levels more in the last century than melting glaciers. The big changes in sea level come from plate tectonics, the widening and narrowing and rising and lowering of the seabed has the greatest affect.
If the people of Fiji and the Solomon Islands check out what is happening along that fault line that is close to them, they may find something other than global warming could make them the next Atlantis.
I'll be very interested to see what Daly has to say about it. The thing is, we'll only get his side of the story from his Web site; and we already know where he's coming from, based on the caption of the picture at the top of the Web site.
"Media reports of sea level rise here are false as a tide gauge at this very site registered depths of 2ft at the very lowest of tides in the 1840s."
What we need are BOTH sides of the story, which means we also need the paper that was just published in International Hydrological Review. I decided over the weekend to see if I can get it by request from the authors. They may be able to either email a PDF version of it or send it to me by mail.
They also may be fielding a lot of similar requests, so I don't know if they'll be able to send me one or not. But it can't hurt to try.
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