Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Archives for August 2005

Katrina and The Mississippi

By

New Orleans in the southern US has been devastated by Hurricane Katrina. According to tonights ABC television news, 80% of the city is under water.

I was in Louisiana in February 1999 and remember enjoying a meal of crawfish in Baton Rouge (just north of New Orleans) and hearing about Hurricane Betsy in 1965 and how New Orleans is sinking anyway – how one day it will dissapear into the Gulf of Mexico.

I have found this photo of the Mississippi River at New Orleans taken in 1999. And to put the region in some perspective, the Mississippi drains a catchment of over 1 million square miles, collecting water from 32 US states, before reaching New Orleans and the sea – according to a powerpoint I did in 1999 that I have just found. Check out this old slide: Mississippi drainage basin .

According to my book Roadside Geology of Louisiana:

“Louisiana hosts nearly 40% of the wetlands of the United States, and they are disappearing at a rapid rate. About 35 square miles of wetland in Louisiana slip away each year, an important loss of habitat to innumerable species of birds, animals, fish and plants. Public attention has focused on wetland loss in Louisiana in recent years, and blame flies in many directions. In truth the phenomenon is largely due to natural geological proceses, though human intervention certainly plays a significant role.”

The book by Darwin Spearing (published by Moutain Press Publishing Co, Missoula, Montana, 1995) goes on to explain how 7,000 years of delta construction is being lost to subsidence during the past few thousand years:

“… before humans ever dredged a channel, build a control levee, or cut through a marsh to reach an offshore oil platform. … whether deltas and their wetlands survive or sink benealth the sea hinges on the fine balance between sediment and subsistence. Deltas tend to sink as their soft and watery mud compacts beneath the weight of more mud laid on it. If no new sediment is added to the top of the pile, the top of the delta will sink beneath the waves. If the supply of sediment delivered to the delta exceeds the sinking rate, the delta will continue to grow and wetlands will expand.

…Nevertheless, tinkering human hands have certainly accelerated wetland loss during the last century. Their principle contribution has been construction of continuous levees along the Mississippi River from Baton Rouge to Venice. The levees do contain floods, but they also deprive the marshes of the sediment they need to stay above sea level. Furthermore, the levees force the river to dump all its sediment at the extreme end of the delta, where waves and currents cannot rework it into sandy coastlines as they did before the levees were build. Much of the sediment slides down the continental slope and onto the Mississippi fan on the deep ocean floor.

… The second major human contributor to wetland destruction (and the sinking of New Orleans) through sediment loss is outside Louisiana. Scores of dams were build during the past century upriver in the Mississippi drainage and in its tributories. They were designed to control floods, generate electricity, store fresh water, and provide recreation. They also trap so much sediment that what reaches Louisiana is only about half that of a century ago.”

So this explains why New Orleans is below sealevel.

And for those who want to argue climate change, I received the following from Benny Peiser:

After reading the round-up of German newspaper editorials in Spiegel Online, one can’t be blamed for thinking that global warming is leading to an increase in the number and intensity of hurricanes hitting the US mainland (strangely, Halliburton was not mentioned as the culprit in this present storm). Going back to 1851, what does the actual data from NOAA (http://www.nhc.noaa.gov/pastdec.shtml) say:

Fig 1: The average number of all hurricanes per decade (in red) is 17.7
http://eurota.blogspot.com/2005/08/eu-environmentalism-score-another-one.html

Fig 2: The average number of major hurricanes per decade (in red) is 6.0
http://eurota.blogspot.com/2005/08/eu-environmentalism-score-another-one.html

Of course, 2001-2004 is not a complete decade. If you think the increase in the number and intensity of hurricanes is due to global warming, be glad I did not add trend lines. There are plenty of real environmental problems to consider, save the global warming hype.

Knowing the above facts, consider the statement by Germany’s Environmental Minister, Jurgen Trittin, a Green Party member (natch):

“There is only one possible route of action,” he writes. “Greenhouse gases have to be radically reduced and it has to happen worldwide. Until now, the US has kept its eyes shut to this emergency. (Americans) make up a mere 4 percent of the population, but are responsible for close to a quarter of emissions.” He adds that the average American is responsible for double as much carbon dioxide as the average European.

“The Bush government rejects international climate protection goals by insisting that imposing them would negatively impact the American economy. The American president is closing his eyes to the economic and human costs his land and the world economy are suffering under natural catastrophes like Katrina and because of neglected environmental policies.”

Why Did Sugar Kill My Plants?

By

I am currently studying biology in Grade 11 at High School. I grew Brassica rapa from seed with a control of just tap water and two treatments with different sugar solutions under 24 hour light.

The control plants (no sugar) flourished and grew to a height of 10.5 cm over 4 weeks. However, the plants receiving sugar solution perished before reaching 1 cm in height.

I was aware that the plants would not be able to utilize the sugar solution as energy, but I was not expecting them to die.

Can anyone who reads my Mum’s blog tell me what affect the sugar might have had on these plants?

Thankyou, Caroline Marohasy

Herd Behaviour

By

Hi Jennifer

I’ve read an interesting article, written in 1989, about ‘herd
behaviour’. You are probably aware of the piece anyway, but just in case I thought I’d mention it. Here’s a section that looks like it relates to current controveries, even though it largely predates it:

Suppose you have some curve between the extreme of this opinion and the extreme of that opinion. You have some indefinite, statistically quite insignificant distribution of opinions. Now in that situation, suppose that the refereeing procedure has to decide where to put money in research, which papers to publish, and so on. What would happen? Well, people would say, “We can’t really tell, but surely we shouldn’t take anybody who is out here. Slightly more people believe in this position than in any other, so we will select our speakers at the next conference from this position on the opinion curve, and we will judge to whom to give research funds,” because the referees themselves will of course be included in great numbers in some such curve. We will select some region there to supply the funds.

And so, a year later what will have happened? You will have combed out some of the people who were out there, and you will have put more people into this region. Each round of decision making has the consequence of essentially taking the initial curve and multiplying it by itself.

Now we understand the mathematical consequence of taking a shallow curve and multiplying it by itself a large number of times. What happens? In the mathematical limit it becomes a delta function at the value of the initial peak. What does that mean? If you go for long enough, you will have created the appearance of unanimity.

The full article is here:

http://www.amasci.com/freenrg/newidea1.html

Stephen Dawson
28th July 2005

To Burn or Graze

By

There has been a bit written at this site about the importance of burning landscapes including comment from David Ward in WA that:

“I have recently developed geometric evidence that frequent burning is the only (repeat only), way to maintain a reasonably fine grained fire mosaic, with small, mild, and controllable fires; a rich diversity of habitat for plants and animals; and protection of small fire refuges for that minority of plants and animals which are not adapted to frequent fire. Aborigines clearly knew, and still, in some parts, know this. Anyone who does not understand should go and talk to an Aboriginal Elder.

“It can be demonstrated, with geometric certainty, that any deliberate long fire exclusion over large areas, such as a National Park, will lead inevitably (repeat inevitably) to large fierce fires, and a coarser mosaic, with little diversity of food and shelter for animals. Small refuges, important for some rare plants and animals, will be destroyed by the ferocity of the fires.”

I have just discovered Christine Jones’ website at http://www.amazingcarbon.com/ courtesy of Graham Finlayson.

Jones suggests that regular burning is extremely detrimental to soft forms of native ground cover and encourages a dominance of relatively unpalatable grasses, removes surface litter leaving the soil unprotected, reduces potential for nutrient cycling, reduce water-holding capacity and degrade soil structure. … concluding that “fire is a tool which should be used cautiously and infrequently”.

Jones suggests that the recruitment of productive native legumes and grasses is favoured by mulching which is destroyed by regular burning.

Jones promotes grazing on the basis that “The open, park-like appearance of many areas at the time of European settlement has often been attributed to indigenous burning regimes. More recent evidence suggests that the healthy grasslands and friable soils described by the first settlers were more likely to have reflected the high abundance of small native mammals, such as bettongs and potoroos most of which are now locally extinct … with the loss of the regenerative effects of small native mammals in Australia since European settlement, managed grazing is now arguably the only natural means by which grasslands can be ‘improved’ in a holitistic way.”

The above is my summary of page 7 and 8 of http://www.lwa.gov.au/downloads/general_doc/46_sti1%20final%20report.pdf, titled ‘Recognise, Relate, Innovate’ by Jones – at the same website.

Are Jones and Ward talking about different landscapes?

Greenpeace Accounts for 2004

By

I was surprised to read The Melbourne’s Age newspaper describe Greenpeace as an ‘eco-fascist concern’:

Multinational stunt outfit Greenpeace Australia Pacific saw its supporter base decline and fund- raising costs blow out in calendar 2004. Accounts just to hand for the eco- fascist concern show that a bigger slice of its fund-raising efforts was swallowed up by costs, to wit, 36per cent compared with 31 per cent previously.

… keeping reading here, http://www.theage.com.au/news/business/some-red-among-the-green-as-costs-rise/2005/08/01/1122748581956.html .

On Government Departments

By

“The trouble, at least on the surface, seems that any government department would rather spend a dollar on simulation than a dime on in-service testing, and the simulation frequently misses vital points while stressing irrelevancies.”

… from a reader of this web-blog