Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

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Bad Moon Rising

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TIDES are a consequence of the gravitational attraction of the earth to both the moon and the sun with the moon generally being more than twice as strong as the sun because it is so much closer to the earth. The moon rotates around the earth with the lunar day approximately 50 minutes longer than then the mean solar day. When the sun and the moon are both pulling in the same direction higher tides, known as spring tides occur.   Really high spring tides are known as king tides.

Gradually the moon and the sun will fall out of step until their pulls are opposing resulting in neap tides.

The size of tides is not only affected by the direction of the gravitational pulls from the moon and the sun, but also their distance from the earth that changes because their orbits are elliptical. The astronomical phenomena while complex are predictable forming cycles that repeat with characteristics unique to each place on earth, tending to vary in predictable ways with topography and sea depth.

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Believing the Oceans Will Keep Warming

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ANTHROPOGENIC Global Warming (AGW) theory is currently the most fashionable climate theory and its proponents have risked much by predicting a continuation in what has been a 150-year general warming trend.

There are already some indications this trend is stalling with no increase in average global atmospheric temperatures for 15 years [1].

For those who subscribe to any one of the many theories that purport to explain natural climate variability the stakes are not so high: whichever way temperatures swing we can claim to be right. Indeed simply claiming that climate change is natural does not constitute a theory amenable to falsification.

There has been some arguing recently over ocean temperatures, in particular heat content, and how it is trending. I am happy to concede the AGW proponents might have one remaining residual warming trend to cling to here.

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Wise Words from Wine Man Philip White: Concerning Murray Mouth Barrages

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PASSIONATE about the wine industry, Philip White grew up in the Bremer Valley of the Lower Murray. He now lives on the opposite side of the South Mount Lofty Ranges at McLaren Vale. He tastes wine and writes about wine, and the wine growing regions of South Australia.

Today he was judging at the inaugural Currency Creek Wine Show. Currency Creek empties directly into Lake Alexandrina. Mr White describes it as, “A small, but very pretty appellation on an estuarine river system flowing into the lakes at the mouth of the Murray.”

And I love his description of the Currency Creek region more generally:

“Cross that range and you’re in rain shadow country, where Currency Creek and its neighbouring stream, the Finniss, flow out of Mosquito Hill country, Cox’s Scrub and Ashbourne, toward the south-east. Into the Murray estuary.

Over that way the stones are more aggro and tortured, and vary from the heavily-mineralised metamorphic schists of Kanmantoo, where I grew up on the Bremer River, to the intensely-varied fruitcake of chaos some big glacier dumped where the Finniss escapes the hills. It’s highly picturesque, from the almost English pubbiness out Ashbourne way, with European trees (just outside the declared region), to the wild reaches of samphire and reeds between the old river ports of Milang and Goolwa.

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Unable and Unwilling to Consider the Evidence: Our ABC

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SCIENCE was once about matching theory with reality. According to American physicist and historian Thomas Kuhn this perhaps more than anything else contributed to the phenomenal progress made by scientists over the last 400 years.

But many people appear to have a problem with understanding theory and considering it in the context of reality. Consider Anna Rose and her performance on the documentary ‘I Can Change Your Mind About Climate Change’ featured on the Australian Broadcasting Corporation (ABC) this evening. Ms Rose was flown across Australia and around the world to talk with climate change sceptics but refused to engage constructively on issues of scientific evidence. Yet evidence is central to science and in particular determining whether theory and reality match.

Instead of listening to what Richard Linzen had to say about feedback mechanism and global climate she said he was not credible because of his views on passive smoking. When it came to Marc Morano, another person introduced to her as sceptical of anthropogenic global warming, Anna Rose point blank refused to talk with him because she said he was a liar. Clearly Mr Morano is influential, here was an opportunity for Anna Rose to apparently show him up as a liar, and she would not engage.

Nick Minchin, who travelled with Ms Rose and who had been specifically tasked with attempting to change Anna Rose’s mind, also tried with the evidence, but he didn’t see able to engage her either.

Jo Nova, David Evans, Richard Lindzen and Marc Morano all provided data that would suggest the theory as promoted by Anna Rose does not accord with reality, but she would not engage.

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Supernovae Affecting Global Climate and Ocean Biodiversity and Productivity

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REMEMBER Henrick Svensmark and Eigil Friis-Christensen and cosmic ray theory [1]: the idea from these Danish physicists and climate scientists that global climate may be mediated by changes in the flux of galactic cosmic rays because cosmic ray are conducive to cloud formation?

Henrik Svensmark has just published a new paper: now available for download in full from the front page of the Royal Astronomical Society’s website [2] and the subject of a detailed post by Anthony Watt [3].

The new paper focuses on local supernova rates (rates of explosions of large stars) and suggests that high rates of explosion could coincide with colder conditions on planet earth. The paper draws a correlation between long-term changes in sea-level and supernova rates and marine biodiversity and productivity over the last 510 million years.

Dr Svensmark goes as far as to hypothesis that the biodiversity and primary productivity of the oceans depends on the supernova rate; somewhat counter intuitively that glacial conditions will result in increased primary productivity.

“A simple working hypothesis, suggested by carbon-isotope data for the past 4 Gyr (Svensmark 2006a), is that primary productivity increases in glacial conditions, perhaps because of better nutrient supplies, caused by a more vigorous mixing in the oceans during cold conditions. This hypothesis would predict the following.

(i) 
A drawdown of CO2 from the environment in glacial conditions. Since organic productivity consumes CO2, there should be an impact on the levels of atmospheric and oceanic CO2. High productivity draws down CO2, until ultimately the productivity rise is halted not only by exhaustion of nutrients, but also by the scarcity of CO2, which should prevent a total loss of environmental CO2. Conversely, low productivity should result in an accumulation of underemployed CO2.

(ii) 
Due to the increased organic productivity, an increase in the heavy stable isotope of carbon, 13C, is expected in the oceans during glacial conditions.

I’m fascinated.  But not convinced.

H/T Neville.

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[1] Cosmic Rays, Clouds and Climate (Part 1) https://jennifermarohasy.com.dev.internet-thinking.com.au/2008/04/cosmic-rays-clouds-and-climate-part-1/

[2] Henrick Svensmark 2012. Evidence of nearby supernovae affecting life on Earth. Monthly Notices of the Royal Astronomical Society.
Links here:
http://www.ras.org.uk/news-and-press/219-news-2012/2117-did-exploding-stars-help-life-on-earth-to-thrive
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2012.20953.x/full

[3] Svensmark’s Cosmic Jackpot: Evidence of nearby supernovae affecting life on Earth at Watts Up With That? http://wattsupwiththat.com/2012/04/24/svensmarks-cosmic-jackpot-evidence-of-nearby-supernovae-affecting-life-on-earth/#more-61941

Beach Mounds Not Middens

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WALKING on the beach this afternoon I took some photographs of beach mounds. I’m referring to piles of shells and pebbles regularly positioned between, and parallel to, the high and low tide marks.

Are these beach mounds a consequence of the ebb tide dragging the sand away from the shells and pebbles or a consequence of swash action dropping shells and pebbles?

During periods of global sea level rise there is typically an overall increase in the amount of sand deposited along a beach.

But a small change in the relative strength of the ebb tide can presumably significantly change the patterns we see on beaches. How different would our beaches look if global sea levels were falling rapidly?

Large mounds dominated by a single shell species near Weipa on Cape York Peninsula (North Queensland) were once considered aboriginal middens but may in fact have been beach mounds. According to Tim Stone from the Australian National University they are not middens by rather a natural consequence of local chenier plain development.[1]

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[1] Shell mound formation in coastal northern Australia by Tim Stone
Marine Geology, Volume 129: 77-100. 1995

Abstract
Shell mounds are late Holocene deposits typically dominated by a single shell species. In northern Australia these mounds are associated with prograding coastal plains. The largest and most numerous are at Weipa on Cape York Peninsula. Archaeologists claim that these mounds were formed by generations of shellfishing Aborigines. This hypothesis is false because most of the shells from the type-site are of a similar radiocarbon age. Mapping and augering of two contrasting shell mound environments along the Mission River at Weipa demonstrates that mound formation is a natural consequence of local chenier plain development. This is supported by shell ages from across the Weipa landscape. The shell mounds at Prumanung originated as a coarse shell berm. The large mounds on the Uningan plain originated as small shell cheniers. The only reasonable explanation for the transformation of these natural shell deposits into tall, steep-sided mounds is the mound-building behaviour of the Orange-footed Scrubfowl Megapodius reinwardt. Similar mounds composed predominantly of sand and gravel are also present at these localities. The strong likelihood that the shell mounds are natural shell deposits raises serious questions about basic principles of shell midden archaeology. New methods for distinguishing between cultural and natural shell deposits are needed.

http://www.sciencedirect.com/science/article/pii/0025322795001018